[Association between atrial fibrillation reoccurrence and new-onset ischemic stroke among patients with nonvalvular atrial fibrillation]

Objective: Explore the association between atrial fibrillation (AF) reoccurrence and new-onset ischemic stroke (IS) in patients with nonvalvular AF, and explore whether there is a high-risk period of IS after recurrent episodes of AF. Methods: A nested case-control study design was used. A total of 565 nonvalvular AF patients with new-onset IS after a follow-up of at least 2 years in the China-AF cohort were enrolled as the case group, and 1 693 nonvalvular AF patients without new-onset IS were matched as the control group at a ratio of 1∶3. Frequency and types of recurrent AF in the previous 1 or 2 years were compared between two groups, and the adjusted associations of AF reoccurrence with new onset IS were explored using conditional logistic regression analysis. The proportion of recurrent AF was compared between the case period and control period, and conditional logistic regression analysis was performed to calculate adjusted associations of case-period AF with IS. Results: The nested case-control study design results showed that the proportion of at least one record of recurrent AF in the previous 1 year was higher in the case group than in the control group (72.0% vs. 60.8%, P<0.05), and the recurrent AF was positively correlated with new-onset IS (adjusted OR=1.80, P<0.001). Similar results were also observed in the previous 2 years period. The case-crossover study design analysis showed that among 565 patients with new-onset IS, recurrent AF in the case period was positively correlated with IS (adjusted OR=1.61, P=0.003). Conclusion: Recurrent AF is associated with IS, and there may be a high-risk period of IS after recurrent episodes of AF.

[Analysis of dyslipidemia management status in atrial fibrillation patients with very high and high risk of atherosclerotic cardiovascular disease]

Objective: To analyze the status of statins use and low-density lipoprotein cholesterol (LDL-C) management in patients with atrial fibrillation (AF) and very high/high risk of atherosclerotic cardiovascular disease (ASCVD) from Chinese Atrial Fibrillation Registry (CAFR). Methods: A total of 9 119 patients with AF were recruited in CAFR between January 1, 2015 to December 31, 2018, patients at very high and high risk of ASCVD were included in this study. Demographics, medical history, cardiovascular risk factors, and laboratory test results were collected. In patients with very high-risk, a threshold of 1.8 mmol/L was used as LDL-C management target and in patients with high risk, a threshold of 2.6 mmol/L was used as LDL-C management target. Statins use and LDL-C compliance rate were analyzed, multiple regression analysis was performed to explore the influencing factors of statins use. Results: 3 833 patients were selected (1 912 (21.0%) in very high risk of ASCVD group and 1 921 (21.1%) in high risk of ASCVD group). The proportion of patients with very high and high risk of ASCVD taking statins was 60.2% (1 151/1 912) and 38.6% (741/1 921), respectively. Attainment rate of LDL-C management target in patients with very high and high risk were 26.7% (511/1 912) and 36.4% (700/1 921), respectively. Conclusion: The proportion of statins use and attainment rate of LDL-C management target are low in AF patients with very high and high risk of ASCVD in this cohort. The comprehensive management in AF patients should be further strengthened, especially the primary prevention of cardiovascular disease in AF patients with very high and high risk of ASCVD.

[Current use of oral anticoagulation therapy and influencing factors among coronary artery disease patients with nonvalvular atrial fibrillation in China]

Objective: To investigate current use of oral anticoagulant (OAC) therapy and influencing factors among coronary artery disease (CAD) patients with nonvalvular atrial fibrillation (NVAF) in China. Methods: Results of this study derived from "China Atrial Fibrillation Registry Study", the study prospectively enrolled atrial fibrillation (AF) patients from 31 hospitals, and patients with valvular AF or treated with catheter ablation were excluded. Baseline data such as age, sex and type of atrial fibrillation were collected, and drug history, history of concomitant diseases, laboratory results and echocardiography results were recorded. CHA₂DS₂-VASc score and HAS-BLED score were calculated. The patients were followed up at the 3rd and 6th months after enrollment and every 6 months thereafter. Patients were divided according to whether they had coronary artery disease and whether they took OAC. Results: 11 067 NVAF patients fulfilling guideline criteria for OAC treatment were included in this study, including 1 837 patients with CAD. 95.4% of NVAF patients with CAD had CHA₂DS₂-VASc score≥2, and 59.7% of patients had HAS-BLED≥3, which was significantly higher than NVAF patients without CAD (P<0.001). Only 34.6% of NVAF patients with CAD were treated with OAC at enrollment. The proportion of HAS-BLED≥3 in the OAC group was significantly lower than in the no-OAC group (36.7% vs. 71.8%, P<0.001). After adjustment with multivariable logistic regression analysis, thromboembolism(OR=2.48,95%CI 1.50-4.10,P<0.001), left atrial diameter≥40 mm(OR=1.89,95%CI 1.23-2.91,P=0.004), stain use (OR=1.83,95%CI 1.01-3.03, P=0.020) and β blocker use (OR=1.74,95%CI 1.13-2.68,P=0.012)were influence factors of OAC treatment. However, the influence factors of no-OAC use were female(OR=0.54,95%CI 0.34-0.86,P=0.001), HAS-BLED≥3 (OR=0.33,95%CI 0.19-0.57,P<0.001), and antiplatelet drug(OR=0.04,95%CI 0.03-0.07,P<0.001). Conclusion: The rate of OAC treatment in NVAF patients with CAD is still low and needs to be further improved. The training and assessment of medical personnel should be strengthened to improve the utilization rate of OAC in these patients.

[The timing of pericardial drainage catheter removal and restart of the anticoagulation in patients suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran: Experiences from 20 cases]

Objective: To investigate the timing of pericardial drainage catheter removal and restart of the anticoagulation in patients with atrial fibrillation (AF) suffered from perioperative pericardial tamponade during atrial fibrillation catheter ablation and uninterrupted dabigatran. Methods: A total of 20 patients with pericardial tamponade, who underwent AF catheter ablation with uninterrupted dabigatran in Beijing Anzhen Hospital from January 2019 to August 2021, were included in this retrospective analysis. The clinical characteristics of enrolled patients, information of catheter ablation procedures, pericardial tamponade management, perioperative complications, the timing of pericardial drainage catheter removal and restart of anticoagulation were analyzed. Results: All patients underwent pericardiocentesis and pericardial effusion drainage was successful in all patients. The average drainage volume was (427.8±527.4) ml. Seven cases were treated with idarucizumab, of which 1 patient received surgical repair. The average timing of pericardial drainage catheter removal and restart of anticoagulation in 19 patients without surgical repair was (1.4±0.7) and (0.8±0.4) days, respectively. No new bleeding, embolism and death were reported during hospitalization and within 30 days following hospital discharge. Time of removal of pericardial drainage catheter, restart of anticoagulation and hospital stay were similar between patients treated with idarucizumab or not. Conclusion: It is safe and reasonable to remove pericardial drainage catheter and restart anticoagulation as soon as possible during catheter ablation of atrial fibrillation with uninterrupted dabigatran independent of the idarucizumab use or not in case of confirmed hemostasis.

[Efficacy and safety of radiofrequency catheter ablation of septal hypertrophy guided by intracardiac echocardiography in hypertrophic obstructive cardiomyopathy]

Nine patients identified as hypertrophic obstructive cardiomyopathy (HOCM) in Beijing Anzhen Hopspital who underwent ablation from March to July 2019 were included in the study. All patients had left ventricular outflow tract gradient (LVOTG) over 50 mmHg(1 mmHg=0.133 kPa)with significant symptoms despite not optimal drug therapy. Intracardiac echocardiography (ICE) was used to reconstruct septum and surrounding structures, and monitor the effect of ablation during procedure. Nine patients with HOCM were included,.of which 6 men and 3 women. The average age was (51.7±12.2) years. All patients underwent successful ablation after a mean of procedural time of (152.2±31.9) minutes and ablation time of (838.4±227.3) seconds. Except for one patients, all other patients had significant LVOTG reduction(P=0.001)within 50 mmHg after the procedure. Systolic anterior motion of the mitral valve disappeared in all patients after the procedure without major periprocedural complications. The LVOTG of these patients remained stable during follow-up. Radiofrequency ablation using ICE guidance is feasible in treating HOCM with promising efficacy and safety.

[A comparison of CAS risk model and CHA2DS2-VASc risk model in guiding anticoagulation treatment in Chinese patients with non-valvular atrial fibrillation]

Objective: To compare the differences between CAS risk model and CHA₂DS₂-VASc risk score in predicting all cause death, thromboembolic events, major bleeding events and composite endpoint in patients with nonvalvular atrial fibrillation. Methods: This is a retrospective cohort study. From the China Atrial Fibrillation Registry cohort study, the patients with atrial fibrillation who were>18 years old were randomly divided into CAS risk score group and CHA₂DS₂-VASc risk score group respectively. According to the anticoagulant status at baseline and follow-up, patients in the 2 groups who complied with the scoring specifications for anticoagulation were selected for inclusion in this study. Baseline information such as age and gender in the two groups were collected and compared. Follow-up was performed periodically to collect information on anticoagulant therapy and endpoints. The endpoints were all-cause death, thromboembolism events and major bleeding, the composite endpoint events were all-cause death and thromboembolism events. The incidence of endpoints in CAS group and CHA₂DS₂-VASc group was analyzed, and multivariate Cox proportional risk model was used to analyze whether the incidence of the endpoints was statistically different between the two groups. Results: A total of 5 206 patients with AF were enrolled, average aged (63.6±12.2) years, and 2092 (40.2%) women. There were 2 447 cases (47.0%) in CAS risk score group and 2 759 cases (53.0%) in CHA₂DS₂-VASc risk score group. In the clinical baseline data of the two groups, the proportion of left ventricular ejection fraction<55%, non-paroxysmal atrial fibrillation, oral warfarin and HAS BLED score in the CAS group were lower than those in the CHA₂DS₂-VASc group, while the proportion of previous diabetes history and history of antiplatelet drugs in the CAS group was higher than that in the CHA₂DS₂-VASc group, and there was no statistical difference in other baseline data. Patients were followed up for (82.8±40.8) months. In CAS risk score group, 225(9.2%) had all-cause death, 186 (7.6%) had thromboembolic events, 81(3.3%) had major bleeding, and 368 (15.0%) had composite endpoint. In CHA₂DS₂-VASc risk score group, 261(9.5%) had all-cause death 209(7.6%) had thromboembolic events, 112(4.1%) had major bleeding, and 424 (15.4%) had composite endpoint. There were no significant differences in the occurrence of all-cause death, thromboembolic events, major bleeding and composite endpoint between anticoagulation in CAS risk score group and anticoagulation in CHA₂DS₂-VASc risk score group (log-rank P =0.643, 0.904, 0.126, 0.599, respectively). Compared with CAS risk score, multivariable Cox proportional hazards regression models showed no significant differences for all-cause death, thromboembolic events, major bleeding and composite endpoint between the two groups with HR(95%CI) 0.95(0.80-1.14), 1.00(0.82-1.22), 0.83(0.62-1.10), 0.96(0.84-1.11), respectively. All P>0.05. Conclusions: There were no significant differences between CAS risk model and CHA₂DS₂-VASc risk score in predicting all-cause death, thromboembolic events, and major bleeding events in Chinese patients with non-valvular atrial fibrillation.

[Predicting value on short-term outcome of various established risk prediction models in extracorporeal membrane oxygenation treated cardiogenic shock patients due to ST-segment elevation myocardial infarction]

Objective: To investigate the predicting value of different risk prediction models for short-term death in patients with ST-segment elevation myocardial infarction (STEMI) complicated by cardiogenic shock and treated with extracorporeal membrane oxygenation (ECMO). Methods: This study was a retrospective case-control study. Forty patients with STEMI complicated by cardiogenic shock who hospitalized in the First Affiliated Hospital of Zhengzhou University from April 2017 to August 2021 and treated with percutaneous coronary intervention (PCI) and ECMO, were enrolled in this study. Patients were divided into survival group and death group according to their clinical outcomes at 30 days after ECMO implantation, and clinical data of the two groups were collected and analyzed. Receiver operating characteristic (ROC) curve and decision curve analysis (DCA) were used to compare the predictive value of ACEF, AMI-ECMO, Encourage and SAVE risk scores for mortality at 30 days after ECMO implantation. According to the evaluation results of DCA, the optimal risk score was selected. Kaplan-Meier curve estimating the 30-day survival after ECMO implantation was plotted by grouping risk scores with reference to previous literatures. Results: A total of 40 patients with STEMI combined with cardiogenic shock were included, age was (57.4±16.7) years, 31 (77.5%) patients were male, there were 21 (52.5%) patients in the death group and 19 (47.5%) in the survival group. Compared with the survival group, patients in the death group had higher lactic acid values, higher proportion of anterior descending artery or left main artery lesions, and a higher proportion of acute renal failure and continuous renal replacement therapy during hospitalization (all P<0.05). Compared with survival group, ACEF, AMI-ECMO and Encourage scores were higher in death group, SAVE score was lower in death group (all P<0.05). The ROC curve analysis showed that the area under the curve (AUC) of ACEF, AMI-ECMO, Encourage and SAVE scores in predicting mortality were 0.707, 0.816, 0.757, and 0.677 respectively (P>0.05). ACEF score demonstrated the highest sensitivity (90.5%) and Encourage score exhibited the highest specificity (89.5%). DCA indicated that the AMI-ECMO and Encourage scores had the best performance in predicting the 30-day mortality after ECMO therapy. Kaplan-Meier survival curve analysis showed that the 30-day mortality after ECMO implantation increased with the increase of AMI-ECMO and Encourage scores (log-rank P≤0.001). Conclusions: The 4 scoring systems are all suitable for predicting 30-day mortality after VA-ECMO therapy in patients with ST-segment elevation myocardial infarction complicated by cardiogenic shock. Among them, AMI-ECMO and Encourage scores have better predicting performance.

[Use of oral anticoagulants and related factors among new-onset acute ischemic stroke patients with nonvalvular atrial fibrillation: A report from the China Atrial Fibrillation Registry Study]

Objective: This study aimed to investigate the oral anticoagulant (OAC) usage among new-onset acute ischemic stroke (AIS) patients with nonvalvular atrial fibrillation (NVAF) in China, and to explore the possible influencing factors of influent anticoagulant therapy in these patients. Methods: The NVAF patients who experienced new-onset and non-fatal AIS from August 2011 to December 2018 in the China Atrial Fibrillation Registry (China-AF), were enrolled. The follow-up ended in December 2019. Information including patients' demographic characteristics, medical history, medication usage, which were collected before and after the index stroke, were analyzed. Patients were classified into OAC group or non-OAC group according to OAC usage within 3 months post stroke. Multivariate logistic regression analysis were conducted to calculate the odds ratios (ORs) of factors which might be associated with OAC usage within 3 months post stroke. Results: A total of 957 new-onset AIS patients were enrolled, 39.4% (377/957) patients were treated with OAC within 3 months after AIS. Covering by high-reimbursement-rate insurance (OR: 1.91, 95%CI: 1.28-2.86, P=0.002), higher number of concomitant drugs (1-2 types OR: 2.10, 95%CI: 1.36-3.23, P=0.001; ≥3 types OR: 2.31, 95%CI: 1.37-3.91, P=0.002) and 3-month-peri-stroke AF recurrence (OR: 3.34, 95%CI: 2.34-4.76, P<0.001) were associated with OAC usage within 3 months post stroke, while higher HASBLED score (OR: 0.49, 95%CI: 0.40-0.60, P<0.001) and pre-stroke antiplatelet usage (OR: 0.29, 95%CI: 0.20-0.43, P<0.001) were related to no OAC usage within 3 months post stroke. Conclusions: In China, the proportion of NVAF patients who initiated OAC therapy within 3 months after new-onset AIS is as low as about 39.4%. Factors related to the OAC usage within 3 months post stroke are 3-month-peri-stroke AF recurrence, number of concomitant drugs and patients with high-reimbursement-rate insurance coverage, but higher HASBLED score and pre-stroke antiplatelet usage are related to no OAC usage within 3 months post stroke.

[The relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation]

Objective: To explore the relationship between fasting blood glucose level and thromboembolism events in patients with non-valvular atrial fibrillation (NVAF). Methods: This was an observational study based on data from a multicenter, prospective Chinese atrial fibrillation registry cohort, which included 18 703 consecutive patients with atrial fibrillation (AF) in 31 hospitals in Beijing from August 2011 to December 2018. Patients were divided into 5 groups according to status of comorbid diabetes and fasting glucose levels at admission: normal blood glucose (normal glucose group), pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group. Patients were followed up by telephone or outpatient service every 6 months. The primary follow-up endpoint was thromboembolic events, including ischemic stroke and systemic embolism. The secondary endpoint was the composite endpoint of cardiovascular death and thromboembolic events. Kaplan-Meier survival analysis and multifactorial Cox regression were used to analyze the correlation between fasting glucose levels and endpoint events. Results: The age of 18 703 patients with NVAF was (63.8±12.0) years, and there were 11 503 (61.5%) male patients. There were 11 877 patients (63.5%) in normal blood glucose group, 2 023 patients (10.8%)in pre-diabetes group, 1 131 patients (6.0%) in strict glycemic control group, 811 patients in average glycemic control group and 2 861 patients(4.3%) in poor glycemic control group. Of the 4 803 diabetic patients, 1 131 patients (23.5%) achieved strict glycemic control, of whom 328 (29.0%) were hypoglycemic (fasting blood glucose level<4.4 mmol/L at admission). During a mean follow-up of (51±23) months (up to 82 months), thromboembolic events were reported in 984 patients (5.3%). The survival curve analysis of Kaplan Meier showed that the incidence rates of thromboembolic events in normal glucose group, pre-diabetes group, strict glycemic control group, average glycemic control group and poor glycemic control group were 1.10/100, 1.41/100, 2.09/100, 1.46/100 and 1.71/100 person-years, respectively (χ²=53.0, log-rank P<0.001). The incidence rates of composite endpoint events were 1.86/100, 2.17/100, 4.08/100, 2.58/100, 3.16/100 person-years (χ²=72.3, log-rank P<0.001). The incidence of thromboembolic events and composite endpoint events in the other four groups were higher than that in the normal blood glucose group (P<0.001). Multivariate Cox regression analysis showed that compared with normal glucose group, the risk of thromboembolism increased in pre-diabetes group(HR=1.23, 95%CI 1.00-1.51, P=0.049), strict glycemic control group(HR=1.32, 95%CI 1.06-1.65, P=0.013) and poor glycemic control group(HR=1.26, 95%CI 1.01-1.58, P=0.044). Conclusion: Both high or low fasting glucose may be an independent risk factor for thromboembolic events in patients with NVAF.

[Early effect of extracorporeal membrane oxygenation and factors related to early outcome in adult patients with fulminant myocarditis]

Objective: To evaluate the efficacy within the first 24 h post extracorporeal membrane pulmonary oxygenation (ECMO) and the impact of early efficacy on the prognosis of adult patients with fulminant myocarditis (FM). Methods: This retrospective case analysis study included hospitalized patients (age≥18 years) who were diagnosed with fulminant myocarditis from November 2016 to May 2021 in the First Affiliated Hospital of Zhengzhou University. Patients were divided into survival or non-survival groups according to treatment outcomes. The age, sex, treatments, drug use, ECMO use, clinical and laboratory data (before and 24 h after the use of ECMO) were analyzed. The change rate of clinical and laboratory data after 24 h use of ECMO was calculated to find differences between two groups. Multivariate logistic regression was used to analyze the related factors with in-hospital death and complication between the two groups. Results: A total of 38 FM patients treated with ECMO were included. There were 23 cases (60.5%) in the survival group, aged (39.6±13.7) years, and 17 (73.9%) cases were female. The total ECMO time was (134.4±71.3)h. There were 15 cases (39.5%) in non-survival group, aged (40.0±15.8) years, and there were 12(80.0%) female, the ECMO time was (120.1±72.4) h in this group. The proportion of tracheal intubation and continuous renal replacement therapy in the survivor group and dosage of norepinephrine within 24 h after ECMO implantation were significantly less than in non-survival group (all P<0.05). There was no significant difference in all efficacy related biochemical indexes between two groups before ECMO use. The levels of lactic acid, procalcitonin, creatinine, alanine aminotransferase, aspartate aminotransferase, creatine kinase-MB, cardiac troponin I and N-terminal B-type natriuretic peptide prosoma were significantly less in survival group than in non-survival group at 24 h after the use of ECMO (all P<0.05). Results of multivariate logistic regression analysis showed that the higher 24 h change rate of creatinine (OR=0.587, 95%CI 0.349-0.986, P=0.044) and creatine kinase-MB (OR=0.177, 95%CI 0.037-0.841, P=0.029) were positively correlated with reduced risk of in-hospital mortality. The central hemorrhage and acute kidney injury in survival group were less than in non-survivor group (P<0.05). Conclusions: After 24 h early use of ECMO in FM patients, the improvement of various efficacy related biochemical test indexes in the survival group was better than that in the non-survival group. Faster reduction of creatine kinase-MB and creatinine values within 24 h ECMO use is positively correlated with reduced risk of in-hospital mortality in adult patients with FM.

[Efficacy and safety of non-vitamin K antagonist oral anticoagulants in patients with atrial fibrillation and hypertrophic cardiomyopathy]

Objective: To evaluate the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOAC) in patients with atrial fibrillation (AF) and hypertrophic cardiomyopathy (HCM). Methods: This study was a prospective cohort study. The data of this study were based on the Chinese Atrial Fibrillation Registry (CAFR) Study, which was a prospective, multicenter registry study. The CAFR Study enrolled inpatients and outpatients with AF from 31 hospitals. Patients with AF and HCM were selected from August 2011 to December 2018. The patients were divided into NOAC-treated group and warfarin-treated group. General clinical data, echocardiographic results and treatment options were collected and compared between the two groups. Patients were followed up every 6 months; outcome events included effective endpoint events(thromboembolism)and safety endpoint events(major bleeding). The incidence of endpoint events in both groups was calculated and compared. Cox proportional hazards regression models and Kaplan-Meier survival analysis were performed to determine the association between NOAC use and endpoint events. Results: A total of 393 patients were included (average age: (60.5±11.8) years, 252 men (64.1%)). There were 133 (34.0%) patients in the NOAC-treated group and 260 (66.0%) patients in the warfarin-treated group. Compared with the warfarin-treated group, the patients in the NOAC-treated group had a higher proportion of paroxysmal AF, catheter ablation of AF, a lower proportion of hypertension, ischemic stroke/transient ischemic attack (TIA), lower heart rate, lower usage rate of angiotensin-converting enzyme inhibitors(ACEI)/angiotensin receptor blockers(ARB), β-blockers, non-dihydropyridine calcium channel blockers(NDH-CCB)(P<0.05). There were no significant differences on the echocardiographic results, including interventricular septal thickness, left ventricular posterior wall thickness, left ventricular end-diastolic diameter, left atrial diameter, left ventricular ejection fraction(P>0.05). After a follow-up of 42 (24, 60)months, the incidence rates of thromboembolism were 1.63 and 2.10 events per 100 person-years for NOAC-and warfarin-treated group, and those of major bleeding were 0.66 and 1.03 events per 100 person-years. Kaplan-Meier survival analysis showed survival rates free from endpoint events were similar between NOAC-treated group and warfarin-treated group(thromboembolism-free survival comparison, P=0.476; major bleeding-free survival comparison, P=0.855). Cox multivariate regression analysis revealed that there was no significant difference on risk of thromboembolism(HR=1.21, 95%CI: 0.42-3.50, P=0.720) and major bleeding(HR=1.50, 95%CI: 0.27-8.41, P=0.642) between NOAC-treated and warfarin-treated group. Conclusion: Patients with AF and HCM can be safely and effectively treated with NOAC.

[Safety and effectiveness of left atrial appendage occlusion in patients with atrial fibrillation and end-stage renal disease undergoing long-term hemodialysis]

Objective: To evaluate the safety and effectiveness of left atrial appendage occlusion (LAAO) in patients with atrial fibrillation and end-stage renal disease undergoing long-term hemodialysis. Methods: Six patients with AF and end-stage renal disease(ESRD)on long term hemodialysis who underwent LAAO from March 2017 to March 2021 in Beijing Anzhen Hospital were enrolled. Baseline characteristics such as age, sex, types of arrhythmia, stroke and bleeding score, and continuous dialysis time were collected. Four patients underwent LAAO, two patients underwent the combined procedure of catheter ablation and LAAO. Perioperative treatment and serious complications were recorded. Transesophageal echocardiography was repeated at 45 days and 60 days after the procedure. Telephone follow-up was conducted at 3, 6 and 12 months after the procedure, and every 6 months thereafter. Thromboembolism and major bleeding events and survival were evaluated. Results: The average age was (66.7±17.0) years old, and 5 were male (5/6). There were 4 patients with paroxysmal AF (4/6), and 2 patients with persistent AF (2/6). The mean CHA₂DS₂-VASc score was (4.8±1.5), and the HAS-BLED score was (3.5±1.4). The duration of hemodialysis was 2.6 (1.1, 8.3) years. Successfully Watchman implantation was achieved in all patients. There were no severe perioperative complications, and no device related thrombosis or leaks were observed by transesophageal echocardiography. During a mean of 22.0 (12.0, 32.0) months follow-up, there was no thromboembolism or major bleeding events. A total of 2 patients died, one from sudden cardiac death, and another one from heart failure. Conclusions: LAAO may be a safe and effective therapeutic option for prevention of thromboembolism in patients with atrial fibrillation and end-stage renal disease undergoing long-term hemodialysis, further studies with larger patient cohort are needed to confirm our results.

[Clinical analysis of left atrial appendage occlusion for stroke prevention in elderly patients with atrial fibrillation]

To evaluate the efficacy and safety of left atrial appendage occlusion (LAAO) in patients with atrial fibrillation (AF) over 75 years. A total of 82 patients with AF who underwent LAAO successfully in Beijing Anzhen Hospital from March 2014 to March 2019 were divided into two groups according to age: the elderly group (aged>75 years) and the young group (aged ≤75 years). Risk of perioperative complications and incidence of ischemic stroke and major bleeding during follow-up were retrospectively analyzed. The results showed that there were no significant differences in procedure-related ischemic stroke(0 vs.1.6%,P=0.768) and major bleeding (0 vs.1.6%,P=0.768) during perioperative period between the two groups. No complications as death or pericardial tamponade occurred in the two group. During a (25.9±15.9) months period of followed up, ischemic stroke event rate was 3.6/100 person-years in the elderly group and 4.9/100 person-years in the young group, respectively. Major bleeding event rate was 2.5/100 person-years in the elderly group and 0/100 person-years in the young group, respectively. Compared with the expected ones, the relative risk reduction (RRR) of stroke in the elderly group was more profound than that in the young group (32.0% vs. 25.0%), while the risk of major bleeding in the young group was significantly lower than that in the elderly group (RRR 100% vs. 56.9%). Therefore, LAAO might be suitable for stroke prevention in the elderly AF patients.

[The impact of digoxin on the long-term outcomes in patients with coronary artery disease and atrial fibrillation]

Objective: To investigate the long-term safety of digoxin in patients with coronary artery disease (CAD) and atrial fibrillation (AF). Methods: This was a prospective study, in which 25 512 AF patients were enrolled from China Atrial Fibrillation Registry Study. After exclusion of patients receiving ablation therapy at the enrollment, 1 810 CAD patients [age: (71.5±9.3)years] with AF were included. The subjects were grouped into the digoxin group and non-digoxin group, and were followed up for a period of 80 months. Long-term outcomes were compared between the groups and an adjusted Cox regression analysis was applied to evaluate the risk of digoxin on the long-term outcomes. The primary endpoint was all-cause mortality. Results: The patients were followed up for a median period of 3.05 years. After multivariable adjustment, the Cox regression analysis showed that digoxin significantly increased the risk of all-cause mortality (HR=1.28, 95%CI 1.01-1.61, P=0.038), cardiovascular mortality (HR=1.48,95%CI 1.10-2.00,P=0.010), cardiovascular hospitalization (HR=1.67,95%CI 1.35-2.07,P=0.008) and the composite endpoints (HR=2.02,95%CI 1.71-2.38,P<0.001). In the subgroup of patients with heart failure (HF), digoxin was not associated with the risk of all-cause mortality, but was still associated with the increased risk of cardiovascular mortality (HR=1.44,95%CI 1.05-1.98,P=0.025), cardiovascular hospitalization (HR=1.44,95%CI 1.09-1.90,P=0.010) and the composite endpoints (HR=1.37, 95%CI 1.01-1.70, P=0.004). However, in the subgroup of patients without HF, digoxin was only associated with all-cause mortality (HR=2.56,95%CI 1.44-4.54,P=0.001). Conclusion: Digoxin significantly increased the risk of all-cause mortality in CAD patients with AF, especially in patients without HF.

[Causes of death and influencing factors of atrial fibrillation patients undergoing anticoagulation therapy]

Objective: To investigate the causes of death and predictors in patients with nonvalvular atrial fibrillation (AF) undergoing anticoagulation therapy. Methods: Consecutive anticoagulated nonvalvular AF patients were recruited from the China Atrial Fibrillation Registry (China-AF) Study from August 2011 to December 2018. After exclusion of patients with hypertrophic cardiomyopathy, dilated cardiomyopathy, or loss of follow-up within 1 year, 2 248 patients were included in this analysis. Enrolled patients were followed up were followed up for 3 and 6 months, and then every 6 months. The primary endpoint was death, including cardiovascular death, non-cardiovascular death and undetermined death. The patients were divided into survival group and death group according to the survival status after follow-up. Clinical information such as age and sex was collected. Cox proportional hazards regression was performed to identify associated risk factors for all-cause mortality, and Fine-Gray competing risk model was used to identify associated risk factors for cardiovascular mortality. Results: A total of 2 248 patients with atrial fibrillation receiving anticoagulant therapy died over a mean follow-up of (42±24) months, mean age was (67±10) years old and 41.1% (923/2 248) patients were female. The mortality rate was 2.8 deaths per 100 patient-years. The most common cause of death was cardiovascular deaths, accounted for 55.0% (120/218). Worsening heart failure was the most common cause of cardiovascular deaths (18.3% (40/218)), followed by bleeding events (12.9% (28/218)) and ischemic stroke (8.7% (19/218)). Multivariate Cox regression analysis showed that age (HR = 1.05, 95%CI 1.04-1.07, P<0.001), anemia (HR = 1.81, 95%CI 1.02-3.18, P = 0.041), heart failure (HR=2.40, 95%CI 1.75-3.30, P<0.001), ischemic stroke/transient ischemic attack (TIA)(HR = 1.59, 95%CI 1.21-2.13, P = 0.001) and myocardial infarction (HR = 2.93, 95%CI 1.79-4.81, P<0.001) were independently associated with all-cause death. Fine-Gray competing risk model showed that age (HR=1.05, 95%CI 1.02-1.08, P<0.001), heart failure (HR=2.81, 95%CI 1.79-4.39, P<0.001), ischemic stroke/TIA (HR=1.50, 95%CI 1.02-2.22, P=0.041) and myocardial infarction (HR=3.31, 95%CI 1.72-6.37, P<0.001) were independently associated with cardiovascular death. Conclusions: In anticoagulated nonvalvular AF patients, ischemic stroke represents only a small subset of deaths, whereas worsening heart failure is the most common cause of cardiovascular deaths. Heart failure, ischemic stroke/TIA, and myocardial infarction are associated with increased mortality.

[Efficacy and safety of segmental radiofrequency ablation for isolation of the superior vena cava in patients with atrial fibrillation]

Objective: To analyze the three-dimensional distribution of functional sinus node, right phrenic nerve and superior vena cava(SVC)-right atrial muscle sleeves by three-dimensional electrophysiological technique in patients with atrial fibrillation (AF), and to investigate the efficacy and safety of segmental radiofrequency catheter ablation (RFCA) for isolation of superior vena cava in these patients. Methods: In this retrospective study, we enrolled 136 AF patients who underwent first RFCA in the First Affiliated Hospital of Zhengzhou University from July 2018 to June 2019 and all patients underwent SVC isolation under sinus rhythm. Baseline clinical data of patients were collected. The functional sinus node was defined by activation mapping, pacing was guided by three-dimensional mapping (Carto) system, localization of the right phrenic nerve was defined by pacing map, the superior vena cava-right atrial muscle sleeves was determined according to the change of potential during SVC isolation, segmental RFCA was performed for SVC isolation, the three-dimensional distribution of functional sinus node, right phrenic nerve and superior vena cava(SVC)-right atrial muscle sleeves was determined by three-dimensional electrophysiological technique. Immediate SVC isolation was achieved in all patients. Patients were evaluated immediately after RFCA and patients were followed at 3, 6, 9, and 12 months after RFCA. Holter monitoring was performed every 3 months, the chest radiograph and the SVC ultrasonic examination were performed every 6 months after RFCA. Postoperative complications were assessed. Results: The mean age of the 136 patients with AF was (51.6±14.2) years, 86 (63.2%) were male, 98 cases (72.1%) were paroxysmal AF and 38 cases (27.9%) were persistent AF. Right atrium activation mapping revealed that 17 (12.5%) functional sinus node were located in the SVC, 78 (57.4%) were located at the SVC-right atrium junctions, 41 (30.1%) were located below the junction level. From the head to foot view, 83 (61.0%) functional sinus node were located at the anterior lateral segment of the SVC-right atrium three-dimensional reconstruction model, 34 (25.0%) located at the posterior lateral segment, 15 (11.0%) located at the anterior wall, 4 (2.9%) located at posterior wall or anterior septum. A total of 294 SVC muscle sleeves were detected among all patients, 94 (32.0%) SVC muscle sleeves were located at the anterior septum of the SVC-right atrium three-dimensional reconstruction model, 76 (25.9%) were located at the posterior septum, 21(7.1%) were located at the posterior free wall, 11 (3.7%) were located at the posterior lateral, 27 (9.2%) were located at anterior lateral wall and 65 (22.1%) were located at the anterior free wall. Right phrenic nerve positioned relatively fix, 133 (97.8%) were located at the lateral segment of the SVC-right atrium three-dimensional reconstruction model, 3 (2.2%) were located at the anterior free wall. Sinus rhythm and SVC isolation were successfully restored immediately after RFCA, no significant SVC stenosis, right phrenic nerve palsy and functional sinus node injury occurred immediately post procedure. All patients were followed up for (11.2±3.6) months and none had postoperative complication. Conclusions: Three-dimensional electrophysiological can determine the spatial location of functional sinus node, right phrenic nerve and SVC-right atrial sleeves. On this basis, segmental RFCA is a safe and effective method to achieve complete isolation of SVC.

[Effectiveness and safety of idarucizumab in the management of perioperative complications of atrial fibrillation catheter ablation in atrial fibrillation patients under dabigatran therapy]

Objective: To investigate the efficacy and safety of idarucizumab in the treatment of perioperative cardiac tamponade and thromboembolic events during catheter ablation in atrial fibrillation (AF) patients under dabigatran therapy. Methods: This study was a retrospective analysis enrolling patients under dabigatran therapy, who underwent catheter ablation for AF at Beijing Anzhen Hospital from January 2019 to December 2020 and developed perioperative cardiac tamponade or acute ischemic stroke (AIS) and received idarucizumab to reverse the anticoagulant effect of dabigatran. Patients' age, sex, renal function, coagulation test and safety events at 30 d after idarucizumab administration were collected and analyzed. The clinical presentation and prognosis were also analyzed. Results: A total of 7 patients were included, 2 (2/7) were male, mean age was (66.3±11.2) years, serum creatinine level was (66.3±13.6) μmol/L, estimated glomerular filtration rate was (89.4±11.2) ml·min-1·1.73 m-2, CHA2DS2-VASc and HAS-BLED scores were (3.2±1.9) and (1.3±1.3), respectively. Five patients (5/7) developed cardiac tamponade during the perioperative period and the time interval to the last dose of dabigatran was (6.3±2.6) h. Idarucizumab was given at (36.4±16.7) min after the definitive diagnosis of cardiac tamponade. A significant decrease of activated partial thromboplastin time was achieved after idarucizumab administration in all five cases. Pericardial puncture and drainage were applied to all patients (5/5) with cardiac tamponade, the drainage volume was (1 037.0±846.9) ml, the retention time of pericardial drainage catheter was (27.9±13.9) h, and the recovery time of anticoagulation was (28.4±13.2) h. One patient (1/5) underwent thoracotomy for hemostasis due to excessive blood loss with the aim of ensuring complete hemostasis. Bleeding occurred in 1 patient (1/5) after the first restart of anticoagulation. AIS occurred in 2 patients (2/7) after operation. One case (1/2) received intravenous thrombolysis after receiving 5.0 g idarucizumab, no hemorrhagic transformation was observed, and the recovery process was satisfactory. Another patient in this group experienced significantly prolonged onset time and 5.0 g idarucizumab was applied before intravascular thrombectomy, there was no bleeding complication in this patient after thrombectomy. At the time of discharge, the consciousness was not significantly improved, and the muscle strength of the right lower limb was recovered somehow compared with that before operation. No hypersensitivity reactions or thrombotic events occurred in these patients within 30 days of the administration of idarucizumab. Conclusion: In AF catheter ablation-associated cardiac tamponade and AIS, idarucizumab is safe and effective in rapidly reversing the anticoagulant effect of dabigatran, use of thrombectomy saves valuable time for timely hemostasis and improvement of cerebral blood circulation.

[Efficacy and safety of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma]

Objective: To evaluate the safety and efficacy of catheter ablation in patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma. Methods: Nine patients with new onset atrial arrhythmia and a prior history of left atrial myxoma, who received surgical myxoma excision and catheter ablation between September 2014 and November 2019, were included in the present study. Baseline characteristics, procedural parameters during catheter ablation, severe perioperative adverse events, recurrence rate of arrhythmia and clinical prognosis were analyzed. Kaplan Meier survival analysis was used to define the maintenance rate of sinus rhythm after catheter ablation in this patient cohort. Results: Nine patients were included. The average age was (55.8 ± 9.1) years old (3 male), there were 3 patients (3/9) with paroxysmal atrial fibrillation (PAF) and 6 patients (6/9) with atrial flutter or atrial tachycardia (AFL or AT). Ablation was successful in all patients, there were no perioperative complications such as stroke, pericardial effusion, cardiac tamponade, vascular complications or massive hemorrhage. During a mean follow-up time of 40.0 (27.5, 55.5) months, sinus rhythm was maintained in six patients (6/9) after the initial catheter ablation. The overall sinus rhythm maintenance rate was 2/3. In addition, 1 out of the 3 AF patients (1/3) developed recurrence of AF at 3 month after ablation, and 2 out of the 6 AFL or AT patients (2/6) developed late recurrence of AF or AFL (19 months and 29 months after ablation), two out of three patients with recurrent AFs or AFL received repeated catheter ablation and one patient remained sinus rhythm post repeat ablation. Meanwhile, there was no recurrence of atrial myxoma, no death, stroke, acute myocardial infarction and other events during the entire follow-up period. Conclusions: Catheter ablation is a safe and feasible therapeutic option for patients with new-onset atrial arrhythmia after surgical excision of left atrial myxoma.

[Electrophysiological characteristics and therapeutic efficacy of radiofrequency ablation of focal atrial tachycardia originating from the right atrial appendage during pregnancy]

Objective: To analyze the electrophysiological characteristics and the therapeutic efficacy of irrigated-tip catheter radiofrequency ablation(RFA) without radiation for pregnant women with focal atrial tachycardia(AT) originating from the right atrial appendage (RAA). Methods: Data from 55 women with focal AT, who underwent radiofrequency ablation (RFA) in the First Affiliated Hospital of Zhengzhou University from October 2016 to March 2019, were screened. 2 non-pregnant women with right atrial appendage tachycardia (RAAT) and 4 pregnant women with non-RAAT were excluded. The remaining 49 cases were divided into RAAT during pregnancy group (n=6, including 4 cases of tachycardia-induced cardiomyopathy) and non-pregnant and non-RAAT group (control, n=43). Under the guidance of three-dimensional mapping system, the earliest activation site was identified, RFA with the irrigated catheter without x-ray fluoroscopy was performed in RAAT patients during pregnancy, all patients in control group underwent non-zero-ray ablation. Patients were followed up at 3, 6, 12 months post procedure, and yearly follow up thereafter in outpatient clinic. Electrocardiogram or Holter monitoring was performed during follow up. AT recurrence and surgical complications were recorded during follow up. At 6 months after RFA, echocardiography examination and laboratory examination including N-terminal B-type brain natriuretic peptide measurement were performed in the pregnant patients, delivery results were also recorded in the pregnant patients. The electrophysiological characteristics of RAAT during pregnancy were analyzed, the therapeutic efficacy of RFA was compared between the two groups. Results: This study is a retrospective study. Age ((30.7±6.2)years vs. (57.2±11.7)years), left ventricular ejection fraction ((46.0±12.8)% vs. (60.1±5.9)%), proportions of organic heart disease (0% vs. 58%) were significantly lower in the RAAT patients during pregnancy group than in control group (P<0.05), while proportions of patients with persistent tachycardia (100% vs. 7%), symptoms of chest distress and palpitation (6/6 vs. 49%) and left ventricular ejection farction≤50% (4/6 vs. 9%) were significantly higher in RAAT group than in control group (P<0.05), heart rate was similar between the two groups ((163.7±11.1)beats/minutes vs. (153.7±15.2)beats/minutes, P>0.05). The characteristic P-wave morphology was observed in RAAT patients during pregnancy, i.e, P wave was mostly upright (5/6) in inferior-leads (Ⅱ, Ⅲ, aVF) and in lead I and aVL, deep and wide negative P wave was found in V₁ lead (5/6), and gradually became positive from V₂-V₆. The mean tachycardia cycle length was (361.7±38.5) ms. Three-dimensional mapping showed that the origin points of the 6 RAAT pregnant patients were all scattered in the local region, the local region was ablated accordingly, 2 patients (2/6) received extensive ablation of local areas. Immediate successful rate was similar between the two groups (6/6 vs. 93%). During follow up ((15.3±4.0) months), no complications were observed after RFA, postoperative recurrence rate was similar (1/6 vs. 12%). Uncomplicated delivery was reported in all 6 pregnant RAAT post ablation. Normal cardiac structure and function was observed in the 4 pregnant patients with tachycardia-induced cardiomyopathy post ablation. Compared to pre-ablation phase, reduced left atrial dimension ((30.3±1.3) mm vs. (36.8±6.7) mm, P>0.05), increased left ventricular ejection fraction ((64.0±2.9)% vs. (39.8±10.7)%), reduced left ventricular end-diastolic dimension ((44.8±4.0) mm vs. (60.0±2.9) mm) and reduced N-terminal B-type natriuretic peptide value ((136.2±47.5) ng/L vs. (3 408.4±901.3) ng/L) were observed at 6 months post ablation (P<0.05). Conclusion: The electrophysiological characteristics are suggestive for focal AT originating from RAA during pregnancy. Under the guidance of 3-dimension activation mapping, no fluoroscopic RFA with irrigated-tip catheter is a safe and effective strategy for the treatment of focal RAAT during pregnancy.

[The thromboembolism risk of low-risk atrial fibrillation patients with different clinical characteristics]

Objective: This study explored the thromboembolism risk of low-risk atrial fibrillation (AF) patients (CHA₂DS₂-VASc score of 0 or 1 for male and 1 or 2 for female) with different clinical characteristics to provide the basis for anticoagulation decision-making in these patients. Methods: We prospectively enrolled consecutive 2 862 nonvalvular low-risk AF patients between August 2011 to December 2018 in China-AF (China Atrial Fibrillation Registry) Study, their CHA₂DS₂-VASc score was 0 or 1 for male and 1 or 2 for female. According to their age, sex, presence or absence of hypertension, diabetes mellitus, congestive heart failure, and vascular disease at the time of enrolling, patients were divided into CHA₂DS₂-VASc score 0 score group, 1 score group, and 2 score group. Patients were followed up every 6 months by outpatient clinic visit or telephone interview. The outcome was a thromboembolic event, including ischemic stroke and systemic embolism. Univariate Cox regression analysis was used to compare the thromboembolism risk between the patients with different risk factors and CHA₂DS₂-VASc score 0 group. Results: A total of 2 862 low-risk atrial fibrillation patients were enrolled in this study. 915 patients (32.0%) were female, and age was (55.0±10.7) years old. There were 933 patients (32.6%) in CHA₂DS₂-VASc score 0 group, 1 401 patients (49.0%) in score 1 group and 528 patients (18.5%) in score 2 group. During follow-up (median 1.5 years, 5 811.82 person-years), 33 cases of thromboembolic events were recorded, the annual rate of thromboembolism was 0.57% (95%CI 0.40%~0.80%). The number of thromboembolic events in patients with CHA₂DS₂-VASc score 0, 1 and 2 were 8, 11 and 14, respectively, and the annual thromboembolism event rates were 0.40% (95%CI 0.20%-0.81%), 0.39% (95%CI 0.22%-0.71%) and 1.34% (95%CI 0.80%-2.27%), respectively. The risk of thromboembolism of CHA₂DS₂-VASc score 2 group (HR=3.53, 95%CI 1.48-8.44; P=0.005), especially female patients aged 65-74 years in CHA₂DS₂-VASc score 2 group (HR=2.67, 95%CI 1.63-4.38; P<0.000) was significantly higher than that in patients of CHA₂DS₂-VASc score 0 group. Conclusion: Low-Risk Atrial Fibrillation patients with CHA₂DS₂-VASc score 2, especially female patients aged 65-74 years old with CHA₂DS₂-VASc score 2 are at higher risk of thromboembolism in low-risk AF patients. For such patients, intensified oral anticoagulant therapy might be helpful to reduce the risk of thrombolism.

[Association between duration of digoxin use and adverse outcomes among Chinese patients with atrial fibrillation]

Objective: We aimed to explore the impact of digoxin use on outcomes in Chinese patients with atrial fibrillation (AF). Methods: We used the dataset from the Chinese Atrial Fibrillation Registry, a prospective, multicenter, hospital-based registry study. According to the inclusion and exclusion criteria, 10 472 eligible patients enrolled from August 2011 to December 2016 were included in this ancillary study. The patients were classified into three groups according to the status of digoxin use at study enrollment, patients already receiving digoxin before registry were represented as continuous group, patients initiated on digoxin for the first time were represented as newly group, and patients without digoxin prescription at enrollment were represented as control group. Patients were followed by telephone or outpatient service every 6 months. Kaplan-Meier survival analysis and Cox proportional hazards regression models were used to investigate the association of digoxin use with adverse outcomes (all-cause death, cardiovascular death and cardiovascular hospitalization). Results: In the overall study population, men accounted for 42.8%, and the average age was (66.9±11.8) years. There were 777（7.42%）patients in continuous group, 375 (3.58%) patients in newly group, and 9 320 (89.00%) patients in control group. Compared with the control group, the patients in the newly group and the continuous group were older, had faster heart rate, lower estimated glomerular filtration rate, higher proportion of persistent atrial fibrillation, heart failure, renal insufficiency, diabetes mellitus, ischemic stroke, coronary heart disease, vascular disease and bleeding history. At the same time, the patients in the newly group and the continuous group were treated more often with anticoagulants, antiplatelet drugs, ACE inhibitors or angiotensin receptor blockers, beta-receptor blockers while the proportion of antiarrhythmic drugs was lower as compared to control group (P<0.05). During a median follow-up of 36 months (interquartile range: 18-48 month), risk of all-cause mortality was significantly higher in newly group compared to control group (7.3% vs. 4.7%, P<0.05), the rates of all-cause mortality, cardiovascular death and cardiovascular hospitalization were all higher in continuous group than in control group (8.0% vs. 4.7%; 4.7% vs. 3.0%; 16.7% vs. 11.8%; P all<0.05). After adjustment for age, male, body mass index, blood pressure, heart rate, renal function, AF type, history of stroke, heart failure, diabetes, coronary artery disease and other drugs treatment, the association between newly group and adverse outcomes was not significant, however, digoxin use was associated with increased all-cause mortality (HR 1.26; 95%CI 1.04-1.56; P=0.019), cardiovascular death (HR 1.38; 95%CI 1.08-1.77, P =0.01), and cardiovascular hospitalization (HR 1.10; 95%CI 1.06-1.52, P=0.02) in continuous group. Conclusion: Continuous digoxin use is associated with a significant increase in adverse outcomes among Chinese patients with atrial fibrillation.

[Value of left ventricular myocardial strain derived from cardiac magnetic resonance tissue tracking on differentiating constrictive pericarditis from restrictive cardiomyopathy]

Objective: To compare left ventricular myocardial mechanics detected by cardiac magnetic resonance tissue tracking(CMR-TT) between patients with constrictive pericarditis(CP) and restrictive cardiomyopathy(RCM),and see if those can be used to differentiate CP from RCM patients. Methods: A total of 23 patients with CP, 20 patients with RCM, who hospitalized in Beijing Anzhen Hospital from January 2014 to April 2019 were included in this study and 25 healthy subjects served as control group, all subjects underwent cardiac magnetic resonance examination. Myocardial mechanics were evaluated by 2-dimensional(2D) and 3-dimensional(3D) CMR-TT in terms of global longitudinal strain(GLS), circumferential strain(GCS), radial strain(GRS) and the lateral wall strain to septal wall strain ratio(lateral/septal ratio) of basal, mid-cavity and apical. The diagnostic area under the receiver operating characteristic curve (ROC) was evaluated for differentiating CP from RCM. Results: Age, sex and heart rate were similar between CP and RCM patients(all P>0.05). 2D-GLS, 3D-GLS, GCS and GRS in CP and RCM groups were significantly lower than those in normal control group(all P<0.05).3D-GLS value was significantly lower in RCM patients than in CP patients(P<0.05), the area under the curve (AUC)=0.787(sensitivity 80%, specificity 78%). 3D-GCS was significantly lower in CP group than in RCM group(P<0.05), the AUC=0.737(sensitivity 80%, specificity 65%). However, there was no significant difference between CP and RCM in 3D-GRS(P>0.05). Compared with RCM, the circumferential and radial lateral/septal ratios of the basal were significantly lower in CP group than in RCM group(both P<0.05), AUC=0.737(sensitivity 70%, specificity 83%) and 0.737 (sensitivity 60%, specificity 87%), respectively. The left ventricular myocardial mechanics strain curve of the CP,RCM and normal control were different. The CP patients presented as " rapidly down-a platform" form, the RCM presented as "slowly down" form, and normal control presented as "rapidly down" form. Conclusion: Evaluating the differences in the diastolic process of left ventricular myocardium and left ventricular myocardial mechanics strain curve is helpful to differentiate CP from RCM patients.

[Relationship between C-reactive protein level and incidence of left atrial spontaneous echocardiographic contrast in patients with nonvalvular atrial fibrillation]

Objective: To investigate the relationship between high sensitivity C-reactive protein (hs-CRP) level and incidence of left atrial spontaneous echocardiographic contrast (LASEC) in the patients with nonvalvular atrial fibrillation (AF). Methods: Four hundred and ninety consecutive patients with nonvalvular atrial fibrillation who underwent radiofrequency ablation for the first time from January 1, 2018 to June 30, 2018 in the Department of Cardiology, Beijing Anzhen Hospital were enrolled. According to the results of transesophageal echocardiography before radiofrequency ablation, patients were divided into the group without LASEC (n=338) and the group with LASEC (n=152). hs-CRP was determined by latex enhanced immunoturbidimetry. The relationship between hs-CRP and LASEC in patients with nonvalvular atrial fibrillation was investigated by univariate and multivariate logistic analysis. Results: LASEC was detected in 152 (31%) of 490 patients. Significant differences in age, type of atrial fibrillation, previous embolic events, fibrinogen, D-dimer, the left atrial anteroposterior diameter and CHA(2)DS(2)-VASc scores were found between patients with and without LASEC (all P<0.05). Compared with the group without LASEC, the serum hs-CRP level was significantly higher in the group with LASEC (3.16 (1.30, 5.23) mg/L vs. 0.67 (0.37, 1.48) mg/L, P<0.001). Multivariate logistic regression analysis showed that hs-CRP (OR=1.136, 95%CI 1.060 - 1.217, P<0.001) and D-dimer (OR=1.040, 95%CI 1.011 - 1.070, P=0.007) were independent determinants for LASEC in this patient cohort. Conclusions: hs-CRP is an independent determinant for LASEC in patients with nonvalvular atrial fibrillation. Inflammation may thus be involved in the formation of prethrombotic state in patients with nonvalvular atrial fibrillation.

[Clinical characteristics of left atrial appendage thrombus in patients with hypertrophic cardiomyopathy and non-valvular atrial fibrillation]

Objective: To investigate the incidence and clinical characteristics of left atrial appendage (LAA) thrombus in patients with hypertrophic cardiomyopathy (HCM) and non-valvular atrial fibrillation (AF) . Methods: Data from 10 440 patients with AF who had undergone transesophageal echocardiography (TEE) before cardioversion or catheter ablation at Beijing Anzhen Hospital from April 2006 to December 2018 were retrospectively screened. Two hundred and five HCM patients were included, 820 AF patients with the same CHA(2)DS(2)-VASc score over the same period were selected as the control group. HCM patients were divided into two subgroups based on presence or absence of LAA thrombus/sludge. The baseline of clinical information, transthoracic echocardiographic and TEE measures were compared among all the groups. Receiver operating characteristic (ROC) curve was used to evaluate the diagnostic value of left atrial diameter (LAD) for LAA thrombus/sludge. Multivariate logistic regression analysis was applied to analyze the correlative factors of LAA thrombus/sludge in HCM patients. Results: The incidences of LAA thrombus or sludge were higher in HCM group than in control group (10.7% (22/205) vs. 0.7% (6/820); 8.8% (18/205) vs.7.0% (57/820), P<0.001) . In HCM patients, LAD was significantly larger in LAA thrombus/sludge subjects than in those without thrombus/sludge ((48.9±5.1)mm vs. (45.2±6.1) mm, P<0.001). CHA(2)DS(2)-VASc score was similar between the two subgroups ((2.0±1.4) vs. (1.8±1.4), P>0.05). There was no difference in the rate of patients with a CHA(2)DS(2)-VASc scores ≥2 between the subgroups(62.5% (25/40) vs. 57.0% (94/165), P=0.525). The incidences of LAA thrombus in HCM and AF patients with CHA(2)DS(2)-VASc scores of 0, 1 and 2 were 8.8% (3/34) , 9.6% (5/52) , 11.8% (11/119) , respectively; and the rate of LAA sludge were 8.8% (3/52) , 7.7% (4/52) , 9.2% (11/119) , respectively. The cut off value of LAD for the diagnosis of LAA thrombus/sludge was 44.5 mm. Multivariate logistic regression analysis showed that LAD≥44.5 mm (OR=5.134, 95%CI 1.862-14.156, P=0.002) , non-paroxysmal AF (OR=2.782, 95%CI 1.238-6.252, P=0.013) , previous thromboembolism or stroke (OR=1.820, 95%CI 0.774-4.227, P=0.017) were independent determinants of LAA thrombus/sludge. Conclusions: The incidence of LAA thrombus/sludge is higher in patients with HCM and AF than in AF patients without HCM. The CHA(2)DS(2)-VASc score is similar between HCM and AF patients with LAA thrombus/sludge and those without thrombus/sludge. Patients with CHA(2)DS(2)-VASc score 0-1 are also likely to suffer LAA thrombus/sludge. Left atrial enlargement is associated with LAA thrombus/sludge.

[Association between weight control and recurrence of atrial fibrillation after catheter ablation in overweight and obese patients]

Objectives: This study explored the relationship between weight control and atrial fibrillation (AF) recurrence after catheter ablation in overweight and obese patients. Methods: We prospectively enrolled consecutive 333 overweight and obese patients aged 28 to 87 years old, who underwent catheter ablation for AF in Beijing Anzhen Hospital between October 2015 and February 2016. Data of patients' characteristics, laboratory examination and treatment were collected at baseline. Each patient was followed up at 3, 6 and 12 months after ablation to collect information on weight, AF recurrence, stroke, major bleeding, hospitalization for cardiovascular reasons and death, etc. Patients were divided into weight controlled group (ΔBMI<-1 kg/m(2)) and weight uncontrolled group (ΔBMI≥-1 kg/m(2)), according to the changes in the most recent exposure BMI before AF recurrence in patients with recurrence or the BMI at 12 months' follow-up in patients without recurrence and the BMI at baseline. Multivariate logistic regression was performed to adjust other known risk factors of AF recurrence and to explore the association between weight control and AF recurrence after catheter ablation. Results: There were 54 patients in weight controlled group and 279 patients in weight uncontrolled group. There were no significant differences in age, gender, education level, left atrial size and history of hypertension between the two groups (all P>0.05). The proportion of patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers was higher in the weight controlled group (50.0%(27/54) vs. 34.8%(97/279), P=0.034). However, there was no significant difference in the proportion of patients with obesity (33.3% (18/54) vs. 29.7% (83/279)), paroxysmal AF (59.3% (32/54) vs. 56.6% (158/279)) and AF duration less than 5 years (76.9% (40/52) vs. 65.4% (178/272)) between the weight controlled group and the uncontrolled group. During 1-year follow-up after ablation, the recurrence rate of AF was significantly lower in the weight controlled group than that in the weight uncontrolled group (14.8% (8/54) vs. 32.6%(91/279), P=0.009). Multivariable logistic regression analysis shows that weight control is independently associated with a lower postoperative AF recurrence rate (OR=0.40, 95%CI 0.18-0.90, P=0.026). Conclusion: Weight control is strongly associated with a lower AF recurrence rate after catheter ablation in overweight and obese patients.

[Effect of non-vitamin K antagonist oral anticoagulants on left atrial or atrial appendage thrombi in patients with nonvalvular atrial fibrillation]

Objective: To investigate the effect of non-vitamin K antagonist oral anticoagulants (NOAC) on left atrial or atrial appendage (LA/LAA) thrombi in patients with nonvalvular atrial fibrillation (NVAF). Method: Data from 3 042 patients with atrial fibrillation(AF), who underwent transesophageal echocardiography (TEE) examination before cardioversion or catheter ablation for the detection of LA/LAA thrombus in our department from March 2016 to January 2018 were prospectively analyzed. Among these patients, LA/LAA thrombus was detected by TEE in 57 patients. A total of 19 patients who received dabigatran or rivaroxaban for ≥3 weeks and underwent repeated TEE were included, 38 patients were excluded (7 patients with rheumatic heart disease, 1 patient treated with pericardial decortication, 1 patient treated with surgical repair of endocardial cushion defect, 1 patient with LA thrombus associated with the atrial septal occluder device, 14 patients received warfarin therapy, 14 patients did not receive repeated TEE). Results: First repeated TEE results showed that LA/LAA thrombus was not completely resolved in 4 out of 4 patients treated with dabigatran (110 mg bid) for a median time of 119 (47, 258) days, whereas LA/LAA thrombus was completely resolved in 5 out of 11 patients treated with dabigatran (150 mg bid) for a median time of 80 (58, 147) days. Thrombus was completely resolved in 2 out of 2 patients treated with rivaroxaban (15 mg qd) for 110 days and 95 days respectively, and in 1 out of 2 patients treated with rivaroxaban (20 mg qd) for 91 days. Second repeated TEE was performed in 8 patients. Thrombus was resolved completely in 2 out of 3 patients with undissolved thrombus treated by dabigatran (110 mg bid) after increasing the dabigatran dosage (150 mg bid). Thrombus was resolved in 3 (1 patient prolonged treatment with dabigatran 150 mg bid and 2 patients switched to rivaroxaban 20 mg qd) out of 4 patients with undissolved thrombus under the dabigatran 150 mg bid regimen, whereas the thrombus remained unresolved in 1 patient switched to rivaroxaban (15 mg qd). After receiving rivaroxaban 15 mg bid treatment, the thrombus was finally resolved in 1 patient with undissolved thrombus treated by rivaroxaban 20 mg qd. There was no clinical thromboembolism or major bleeding events during the median follow up time of 462 (305, 558) days. Conclusions: Our data show that NOAC is an effective therapeutic option for the treatment of LA/LAA thrombi. When eligible, a higher NOAC dosage may be preferred due to the higher efficacy on thrombus resolvement.

[Performance of interpreting the variants of long QT syndrome according ACMG guidelines by four clinical gene screening agencies from Beijing]

Objective: To analyze the interpretation results on the pathogenic classification of KCNH2 variants and SCN5A variants of long QT syndrome (LQTS) based on American College of Medical Genetics and Genomics (ACMG) guidelines by 4 clinical gene screening agencies from Beijing. Methods: Pathogenic classification of 16 variants in KCNH2 and SCN5A was made by 4 clinical gene screening agencies from Beijing based on ACMG guideline. Krippendorff's alpha was used to assess the inter-agency variation consistency. Results: All 4 agencies made pathogenic assessment on all the variants and provided the interpretation results for the classification. For the eight variants from the patients with LQTS, the consistency of classification was only 1/8 and the alpha test value was - 0.01. For the eight variables from incidental findings, the consistency of classification was 4/8 and the alpha test value was 0.407. Evidence analysis of the 4 variants with large differences in classification among agencies showed that the main reasons for the discrepancies originated from the comprehensiveness of the literature search and the inconsistency of the subjective determination of the evidence grade. Conclusion: The consistency of the pathogenic classification of LQTS gene variants based on ACMG guidelines among clinical gene screening agencies from Beijing is poor, which will result in great impact on the clinical treatment strategies of the patients with LQTS. The standardization of pathogenic evaluation of variants in clinical gene screening agencies needs to be improved urgently.

[The impact of red blood cell distribution width on outcome of elective percutaneous coronary intervention in non-anemia patients]

Objective: Previous studies have revealed that the red blood cell distribution width (RDW) was associated with long-term prognosis in patients undergoing percutaneous coronary intervention (PCI). However, they did not exclude patients with anemia. This study, thus, investigated the association between RDW and prognosis in non-anemia patients. Methods: A total of 2 732 patients underwent elective PCI from July 2009 to September 2011 were enrolled in the study. These patients were divided into two groups based on their baseline median RDW levels: low RDW group (RDW<12.1%) and high RDW group (RDW≥12.1%). All the subjects were followed up for an average period of 18 months and the associations between baseline RDW levels and postoperative mortality were analyzed. Results: Patients in the high RDW group were elder and had more women than those in low RDW group. Most of them had prior history of hypertension, stroke, myocardial infarction, but few of them were current smokers. Subjects in the high RDW group had higher systolic blood pressure and total cholesterol levels, and lower erythrocyte mean corpuscular volume, hemoglobin level, estimated glomerular filtration rate level, and left ventricular ejection fraction. Moreover, more subjects in the high RDW group were combined with left main, ostial and chronic total occlusion lesion, and had a lower complete revascularization rate. The postoperative mortality was significantly higher in the high RDW group than that in the low RDW group (2.4% vs 0.6%, P<0.001). Multivariate Cox regression analysis revealed that preoperative high RDW level was an independent risk factor for postoperative mortality after adjustment of other factors (HR 3.930, 95%CI 1.600-9.656, P=0.003). Conclusion: High RDW might be a marker for the postoperative mortality in non-anemic patients undergoing elective PCI.

[Situation of long-term use of oral anticoagulation among atrial fibrillation patients with stroke in different level hospital]

OBJECTIVE

To investigate the current situation, time trends and factors associated with long-term use of oral anticoagulation (OAC) among atrial fibrillation (AF) patients with ischemic stroke.

METHODS

We used the dataset from the CAFR (Chinese Atrial Fibrillation Registry), a prospective, multicenter, hospital-based registry study involving 20 tertiary and 12 nontertiary hospitals in Beijing. In brief, 380 consecutive AF patients with following ischemic stroke were enrolled from 2003 to 2014.Patients with valvular AF, radiofrequency catheter ablation history or contraindications of OAC were excluded. We divided the patients into two groups according to hospital level, and investigated the rate of OAC use and its change over time in patients who had indication, the factors including patient characteristics and hospital level associated with OAC use were also analyzed.

RESULTS

Overall oral anticoagulation use rate was 27.71%, which dropped to 22.11% and 15.26% at 6 months and 12 months, respectively.A total of 298 participates were enrolled from tertiary hospitals (78.42%), and 82 were enrolled from nontertiary hospitals. The status of OAC use in tertiary hospitals was better than nontertiary hospitals (32.66% vs 7.32%, P<0.001). Multivariable analysis showed better oral anticoagulation use was independently associated with higher-level hospitals (odds ratio 1.785, 95% confidence interval 1.026-3.106, P=0.040), and history of heart failure (odds ratio 2.247, 95% confidence interval 1.235-4.090, P=0.008).

CONCLUSIONS

These data indicates oral anticoagulation use has improved in atrial fibrillation patients with stroke in Beijing. The use of anticoagulation among the patients from tertiary hospitals is significantly better than those from nontertiary hospitals, and the history of heart failure may have effect on the use of oral anticoagulation.

Effects of selenium and light wavelengths on liquid culture of Cordyceps militaris Link

To investigate the effects of selenium and light wavelengths on the growth of liquid-cultured Cordyceps militaris and the main active components' accumulation, culture conditions as selenium selenite concentrations and light of different wavelengths were studied. The results are: adenosine accumulation proved to be significantly selenium dependent (R(2) = 0.9403) and cordycepin contents were determined to be not significantly selenium dependent (R(2) = 0.3845) but significantly enhanced by selenium except for 20 ppm; there were significant differences in cordycepin contents, adenosine contents, and mycelium growth caused by light wavelengths: cordycepin, blue light > pink light > daylight, darkness, red light; adenosine, red light > pink light, darkness, daylight, blue light; and mycelium growth, red light > pink light, darkness, daylight > blue light. In conclusion, light wavelength had a significant influence on production of mycelia, adenosine, and cordycepin, so lightening wavelength should be changed according to target products in the liquid culture of C. militaris.

Discovery and characterization of taspoglutide, a novel analogue of human glucagon-like peptide-1, engineered for sustained therapeutic activity in type 2 diabetes

AIM

Glucagon-like peptide-1 (GLP-1) receptor agonists for the treatment of type 2 diabetes are administered by daily injection because of short plasma half-lives, which result partly from the biochemical instability of these peptides. There is a medical need for GLP-1 analogues that can be administered less frequently for patient convenience.

METHODS

We synthesized a series of human GLP-1 (hGLP-1(7-36)NH(2) ) derivatives containing α-aminoisobutyric acid (Aib) substitutions, analysed their enzymatic stabilities and evaluated their secondary structures using circular dichroism (CD) and nuclear magnetic resonance (NMR).

RESULTS

Plasma stability experiments showed that only the analogue containing Aib substitutions in both the N-terminus (position 8) and the C-terminus (position 35), [Aib⁸(,)³⁵]hGLP-1(7-36)NH₂ (BIM-51077), was fully resistant to enzymatic cleavage. Incubation with human plasma kallikrein or plasmin confirmed that the Aib substitution at position 35 prevented protease cleavage around this residue, which contributes to the significantly enhanced plasma stability and increased plasma half-life. CD revealed increased C-terminal α-helicity in Aib³⁵-substituted analogues compared with both hGLP-1(7-36)NH₂ and analogues containing only Aib⁸ substitutions. Based on NMR studies, the secondary structure of BIM-51077 is similar to hGLP-1(7-36)NH₂ with a slight increase in α-helicity in the C-terminus. Compared with hGLP-1(7-36)NH₂, BIM-51077 had similar binding affinity for the human GLP-1 receptor and activated this receptor with similar potency.

CONCLUSIONS

We have discovered an Aib⁸(,)³⁵-substituted analogue of native hGLP-1(7-36)NH₂ (BIM-51077) that retains the structure of the native peptide, and has similar activity and enhanced stability. A sustained-release formulation of this molecule (taspoglutide) is in phase-3 clinical development.

The effect of selective sst1, sst2, sst5 somatostatin receptors agonists, a somatostatin/dopamine (SST/DA) chimera and bromocriptine on the “clinically non-functioning” pituitary adenomas in vitro

The aim of the work was to investigate the effects of somatostatin analogs acting selectively on sst1 (BIM-23926), sst2 (BIM-23120) and sst5 (BIM-23206) receptor subtypes on the viability of "clinically non-functioning" pituitary adenomas in vitro. The effects of native SST (SST-14), a SST/DA chimera (BIM-23A387) and a D(2)-dopamine receptor agonist bromocriptine (BC) were also examined. The study was performed on 10 surgically removed pituitary macroadenomas, diagnosed before surgery as "non-functioning". A part of each tumor was mechanically dispersed and digested with collagenase to isolate the tumoral cells. Another part of each tumor was fixed, embedded in paraffin and immunostained to reveal the pituitary hormones and SST receptor subtypes (sst1, sst2A, sst2B, sst3, sst4, sst5). The tumoral cell suspensions were incubated for 24 h with the substances mentioned above. The quantity of viable cells was estimated using the EZ4U system. The results were compared with the immunohistochemical evaluation of the hormonal profile of adenoma and the sst receptor subtype immunoreactivities present. The findings indicate that selective sst1, sst2 and sst5 receptors agonists, SST/DA chimera and D(2)-dopamine receptor agonist bromocriptine affect the viability of some, but not all, "clinically non-functioning" pituitary adenomas in vitro. The most effective was bromocriptine. The investigated somatostatin analogs including SST/DA chimera exerted roughly similar inhibitory effects. Further studies are needed to fully evaluate the potential usefulness of these compounds in the pharmacological treatment of "non-functioning" pituitary tumors.

Endogenous ghrelin regulates episodic growth hormone (GH) secretion by amplifying GH Pulse amplitude: evidence from antagonism of the GH secretagogue-R1a receptor

Ghrelin was purified from rat stomach as an endogenous ligand for the GH secretagogue (GHS) receptor. As a GHS, ghrelin stimulates GH release, but it also has additional activities, including stimulation of appetite and weight gain. Plasma GH and ghrelin secretory patterns appear unrelated, whereas many studies have correlated ghrelin variations with food intake episodes. To evaluate the role of endogenous ghrelin, GH secretion and food intake were monitored in male rats infused sc (6 mug/h during 10 h) or intracerebroventricularly (5 microg/h during 48 h) with BIM-28163, a full competitive antagonist of the GHS-R1a receptor. Subcutaneous BIM-28163 infusion significantly decreased GH area under the curve during a 6-h sampling period by 54% and peak amplitude by 46%. Twelve hours after the end of treatment these parameters returned to normal. Central treatment was similarly effective (-37 and -42% for area under the curve and -44 and -49% for peak amplitude on the first and second days of infusion, respectively). Neither peripheral nor central BIM-28163 injection modified GH peak number, GH nadir, or IGF-I levels. In this protocol, food intake is not strongly modified and water intake is unchanged. Subcutaneous infusion of BIM-28163 did not change plasma leptin and insulin levels evaluated at 1200 and 1600 h. On the contrary, central BIM-28163 infusion slightly increased leptin and significantly increased insulin concentrations. Thus, endogenous ghrelin, through GHS-R1a, acts as a strong endogenous amplifier of spontaneous GH peak amplitude. The mechanisms by which ghrelin modifies food intake remain to be defined and may involve a novel GHS receptor.

Use of the excluded protecting group (EPG) method for peptide synthesis

The excluded protecting group (EPG) method has been used for the solution synthesis of several peptides including Merrifield's Model Tetrapeptide, linear antamanide and an analogue of magainin-1, [Ala(19), Asn(22)]magainin-1. In the approach reported, the C-terminal amino acid is esterified to the 2-position of cholestane as the [2s,3s]iodohydrin ester and the penultimate amino acid added to the aminoacyl-steroid as the Fmoc-pentafluorophenyl-ester. The Fmoc group is removed with Et(2)NH/DMF ( approximately 15% v/v) and, after evaporation to approximately 10 mL, the solution chromatographed on Sephadex LH-20 in DMF. The dipeptidyl-steroid elutes as the free amine well separated from other reaction mixture components. Fractions containing the dipeptide, as determined by counting and TLC, are pooled and reacted with the next Fmoc-amino acid-pentafluorophenyl ester in the sequence. Repetition of the deprotection/purification/reaction cycle yields the fully protected peptide. On completion of the synthesis, the cholestane iodohydrin ester is selectively removed by treatment with Zn degrees /AcOH to yield the peptide with intact alpha-amino and side chain protecting groups. Global deprotection is achieved with HF. All intermediates from the syntheses reported were characterized. The magainin analogue was shown to have full biologic activity. The Fmoc iodohydrin esters of 16 of the 20 proteogenic amino acids have been prepared and characterized for use as the C-terminal amino acids in other EPG syntheses.

Novel ghrelin analogs with improved affinity for the GH secretagogue receptor stimulate GH and prolactin release from human pituitary cells

OBJECTIVE

Ghrelin, a recently identified 28-amino acid peptide is a potent GH secretagogue (GHS) produced predominantly by the stomach. Ghrelin stimulates GH secretion through binding to the GHS receptor in the hypothalamus and pituitary. In addition to the GH-releasing action, ghrelin has been found to be a powerful orexigenic factor. To assess the direct in vitro effects of ghrelin on human pituitary hormone secretion we have produced a panel of novel ghrelin analogs (molecular weight, 3323-3384; human native ghrelin, 3371) with enhanced affinity for the human GHS receptor (IC(50) 0.38-1.09 nM; human ghrelin, 1.2-2.2 nM).

METHODS

The peptidic analogs were tested for their effect on GH secretion using dispersed human fetal pituitaries (21 to 23 weeks of gestation) and cultured GH- and prolactin (PRL)-secreting adenomas. The expression of the GHS receptor in normal (fetal and adult) human pituitary tissues, GH- and PRL-cell adenomas was established using RT-PCR.

RESULTS

The effects of ghrelin, its analogs and GH-releasing hormone (GHRH) alone or in combination on GH and PRL secretion were compared at various concentrations. The ghrelin analogs stimulated GH release by 35-60% from human fetal pituitary cells (1-10 nM; P<0.05) and by 50-75% from cultured pituitary adenomas (10 nM; P<0.05). This releasing effect was dose-dependent, achieving maximal stimulation with analog concentrations at 100 nM. Human ghrelin was less potent as compared with its analogs in stimulating human GH, in keeping with the improved binding affinity of the analogs for the GHS-1a receptor. The ghrelin analogs and GHRH had comparable effects on GH secretion from both normal and adenomatous cells, and in combination produced an additive stimulatory effect on GH (150%; P<0.0001). In contrast, ghrelin and its analogs induced a comparable increase in PRL release ranging between 25 and 40% (P<0.05) from fetal cells and 30 and 70% (P<0.001) from cultured PRL-cell and mixed GH-PRL adenomas.

CONCLUSIONS

Our results have demonstrated for the first time that ghrelin analogs with enhanced affinity for the GHS receptor are potent stimulators of GH secretion from human pituitary cells, and thus may possess potential clinical therapeutic benefits.

Gamma interferon is not required for arthritis resistance in the murine Lyme disease model

Lyme arthritis is the most common complication following infection of human individuals with Borrelia burgdorferi sensu stricto. In mice, B. burgdorferi infection leads to arthritis of the tibiotarsal joints. Arthritis severity in mice is under host genetic control, as BALB/c mice developed mild arthritis but C3H/He mice developed severe disease following B. burgdorferi infection. To study the role of gamma interferon (IFN-gamma) in arthritogenesis, targeted mutant mice lacking the IFN-gamma receptor (IFN-gammaR) were infected by inoculation with B. burgdorferi. IFN-gammaR(-/-) and parental 129/SvEv mice developed mild arthritis of similar severity, as determined both by weekly tibiotarsal joint measurements and histopathology at 2 and 5 weeks postinfection. Both strains of mice had the same spirochetal burden in the joints, suggesting that the IFN-gammaR(-/-) mice were not impaired in controlling spirochetal expansion in vivo. The wild-type mice mounted a Th1 response, with a predominance of CD4(+) IFN-gamma(+) T cells observed by flow cytometry. In contrast, the IFN-gammaR(-/-) mice mounted a Th2 response, with a predominance of CD4(+) IL-4(+) T cells. As expected given their cytokine profile, the IFN-gammaR(-/-) mice produced fewer CD8(+) IFN-gamma(+) and MAC-1(+) IL-12(+) cells and less immunoglobulin G2a (IgG2a) than their wild-type counterparts. These results strongly suggest that IFN-gamma is not required for arthritis resistance or as part of an effective immune response against B. burgdorferi.

Cloning and characterization of six embryogenesis-associated cDNAs from somatic embryos of Picea glauca and their comparative expression during zygotic embryogenesis

Six somatic embryogenesis-associated cDNAs (PgEMB2, 6, 7, 8, 24 and 34) from white spruce (Picea glauca (Moench) Voss) somatic embryos have been characterized. Transcript accumulation during somatic embryo development and subsequent germination related to these genes, indicated that they were developmentally regulated. The transcripts related to clones PgEMB2, 6, 24 and 34 were also detected during zygotic embryo development, but transcripts of clones PgEMB7 and 8 were not. PgEMB24 had a similar gene expression pattern to spruce Em-like late embryo abundant (lea) gene, but other clones had no similarities in gene expression to either spruce lea-like or storage protein genes. Abscisic acid, a stimulator for spruce somatic embryo maturation, did not obviously affect gene expression corresponding to these cDNAs. The predicted proteins are distinguishable from known LEA proteins based on analyses of hydropathy plots, amino acid compositions and deduced protein structures. The similarities of the spruce cDNAs, and protein sequences predicted from these cDNAs, to other sequence data are described.

Characterization of cDNAs representing five abscisic acid-responsive genes associated with somatic embryogenesis in Picea glauca, and their responses their responses to abscisic acid stereostructure

Five abscisic acid (ABA)-responsive cDNAs that were identified by differential screening of a white spruce [Picea glauca (Moench) Voss] cotyledonary somatic embryo cDNA library are characterized. Three of the cDNAs (PgEMB12, 14, 15) are predicted to encode homologues of different late-embryogenesis-abundant (LEA) proteins, a further two (PgEMB 5 and 23) share little similarity to any known DNA or protein sequences. When suspension cultures were fed 1.5 x 10(5) M S-(+)-ABA and assessed for transcript abundance over 48 h, gene expression corresponding to each lea-like gene was inducible and was evident during the 48-h period. Conversely, transcripts were at a very low abundance when suspensions were fed R-(-)-ABA. When suspensions were treated with a range of S-(+)-ABA and R-(-)-ABA concentrations (10(-7)-10(-4) M), expression was induced at S-(+)-ABA concentrations of 10(-5) M or above. Expression corresponding to PgEMB5 and PgEMB23 indicates less specificity for ABA stereostructure, with similar expression patterns being observed for either enantiomer during the 48 h after feeding. The two corresponding genes also appear more responsive to ABA concentration than the predicted lea genes, within the range examined (10(-7)-10(-4) M).

Somatostatin receptor subtype specificity in human fetal pituitary cultures. Differential role of SSTR2 and SSTR5 for growth hormone, thyroid-stimulating hormone, and prolactin regulation

Somatostatin (SRIF), a hypothalamic inhibitor of pituitary growth hormone (GH) and thyroid-stimulating hormone (TSH) secretion, binds to five distinct receptor (SSTR) subtypes. We therefore tested SSTR subtype-specific SRIF analogs in primary human fetal pituitary cultures (23-25-wk gestation) to elucidate their role in regulating human pituitary function. Using reverse transcription-PCR, mRNA expression of SSTR2 and SSTR5 were detected in fetal pituitary by 25 wk. SRIF analog affinities were determined by membrane radioligand binding in cells stably expressing the human SSTR forms. GH secretion was suppressed equally (40-60%, P < 0.005) by analogs preferential for either SSTR2 (IC50 for receptor binding affinity, 0.19-0.42 nM) or SSTR5 (IC50, 0.37 nM), and compounds with enhanced affinity for SSTR2 were more potent (EC50 for GH suppression, 0.05-0.09 nM) than Lanreotide (EC50, 2.30 nM) and SRIF (EC50, 0.19 nM). Similarly, analogs with high affinity for SSTR2 or SSTR5 decreased TSH secretion (30-40%, P < 0.005). However, prolactin was effectively inhibited only by compounds preferentially bound to SSTR2 (20-30%, P < 0.05). Luteinizing hormone was modestly decreased (15-20%) by SSTR2- or SSTR5-specific analogs. An SSTR5-specific analog also exclusively inhibited GH in acromegalic tumor cells. Thus, SRIF regulation of GH and TSH in primary human fetal pituitary cells is mediated by both SSTR2 and SSTR5, both of which are abundantly expressed by 25 wk. In contrast, suppression of prolactin is mediated mainly by SSTR2. These results indicate that SSTR5 is critical for physiologic regulation of GH and TSH. SRIF analogs with selective affinity for this receptor may therefore be more effective in the treatment of hormone-secreting pituitary adenomas.

Endochitinase and beta-1,3-glucanase genes are developmentally regulated during somatic embryogenesis in Picea glauca

Two cDNAs isolated from white spruce [Picea glauca (Moench) Voss] somatic embryos, are predicted to encode a basic class IV chitinase and a beta-1,3-glucanase, respectively corresponding to genes PgChi-1 and PgGlu-1. Each represents a multigene family in spruce. Transcripts homologous to PgChi-1 or PgGlu-1 genes were highly abundant in embryogenic tissues and gradually decreased after tissues were placed on abscisic acid-containing maturation medium, with lowest abundance in globular embryos. Transcripts related to PgGlu-1 became highly abundant again in early cotyledonary embryos but decreased thereafter, whereas transcripts related to PgChi-1 were also highly abundant in late cotyledonary embryos and plantlets in vitro; transcripts were either low (PgChi-1) or were not detectable (PgGlu-1) in needles. Wounding, drying and flooding stresses enhanced PgChi-1- and PgGlu-1-related gene expression. Fungal cell wall suspension enhanced PgGlu-1-related transcript accumulation, but reduced PgChi-1-related transcript abundance within 24 h. PgChi-1 and PgGlu-1 and their homologues may have roles in plant defense, and possibly developmental roles during spruce somatic embryo maturation.