Atrial fibrillation

Is nifekalant more effective than amiodarone in improving the clinical outcomes of catheter ablation in patients with persistent atrial fibrillation?

Background

Traditionally, amiodarone or electrical cardioversion was used if radiofrequency catheter ablation (RFCA) could not terminate atrial fibrillation during the procedure in patients with persistent atrial fibrillation (PeAF).

Objective

To investigate whether the nifekalant instead of amiodarone during RFCA improve procedure outcomes in patients with PeAF.

Methods

This study enrolled patients with PeAF who failed to achieve cardioversion after initial ablation at our center between January 2020 and December 2022. These patients were classified into the nifekalant (N) group and the amiodarone (A) group. And patients were followed for 1 year to evaluate long-term success rates. Subgroup analyses and the logistic regression analyses were performed.

Results

The study comprised 300 participants and included N (n = 121) and A (n = 179) groups. Following propensity score matching (PSM), 101 participants were in each group. Within the N and A groups, 57(56.44 %) and 19(18.81 %) cases successfully terminated AF, 45 (44.56 %) and 15(14.85 %) cases achieved conversion to atrial tachycardia (P < 0.001), respectively. The ventricular tachycardia was observed in only one case in the N group (P > 0.05). The follow-up results demonstrated that one-year success rates were 63.37 % and 49.50 % for the N and A groups (P < 0.05).

Conclusion

For patients with PeAF that persists after initial catheter ablation, compared to amiodarone, administration of nifekalant could convert atrial fibrillation into atrial tachycardia, following by target ablation, has the potential to improve the procedure outcomes.

Global epidemiology of mental disorder in atrial fibrillation between 1998-2021: A systematic review and meta-analysis

BACKGROUND

As the burden of mental disorders among patients with atrial fibrillation (AF) increases, researchers are beginning to pay close attention to the risk and prevalence of these comorbidities. Although studies have independently analyzed the risk of comorbidity with depression and anxiety in patients with AF, no study has systematically focused on the global epidemiology of these two mental disorders.

AIM

To explore the prevalence of depression and anxiety in patients with AF.

METHODS

Five databases were searched from their date of establishment until January 2023. Observational studies reporting the comorbidity of AF with depression and anxiety, were included in this study. Basic information, such as the first author/ publication year, study year, study type, and prevalence of depression and anxiety, were extracted. STATA SE 15.1 was used to analyze the data. Subgroup, meta-regression, and sensitivity analyses were performed to estimate study heterogeneity.

RESULTS

After a thorough search, 26 studies were identified and included in this meta-analysis. The prevalence rates of depression and anxiety in adults with AF were 24.3% and 14.5%, respectively. Among adult males with AF, the prevalence was 11.7% and 8.7%, respectively, whereas in females it was 19.8% and 10.1%, respectively. In older adults with AF, the prevalence rates of depression and anxiety were 40.3% and 33.6%, respectively. The highest regional prevalence of depression and anxiety was observed in European (30.2%) and North American (19.8%) patients with AF.

CONCLUSION

In this study, we found that the prevalence of depression and anxiety among patients with AF varies with sex, region, and evaluation scales, suggesting the need for psychological interventions for patients with AF in clinical practice.

Putative causal relations among gut flora, serums metabolites and arrhythmia: a Mendelian randomization study

BACKGROUND

The pathogenesis of cardiac arrhythmias is multifaceted, encompassing genetic, environmental, hemodynamic, and various causative factors. Emerging evidence underscores a plausible connection between gut flora, serum metabolites, and specific types of arrhythmias. Recognizing the role of host genetics in shaping the microbiota, we employed two-sample Mendelian randomization analyses to investigate potential causal associations between gut flora, serum metabolites, and distinct arrhythmias.

METHODS

Mendelian randomization methods were deployed to ascertain causal relationships between 211 gut flora, 575 serum metabolites, and various types of arrhythmias. To ensure the reliability of the findings, five complementary Mendelian randomization methods, including inverse variance weighting methods, were employed. The robustness of the results was scrutinized through a battery of sensitivity analyses, incorporating the Cochran Q test, leave-one-out test, and MR-Egger intercept analysis.

RESULTS

Eighteen gut flora and twenty-six serum metabolites demonstrated associations with the risk of developing atrial fibrillation. Moreover, ten gut flora and fifty-two serum metabolites were linked to the risk of developing supraventricular tachycardia, while eight gut flora and twenty-five serum metabolites were associated with the risk of developing tachycardia. Additionally, six gut flora and twenty-one serum metabolites exhibited associations with the risk of developing bradycardia.

CONCLUSION

This study revealed the potential causal relationship that may exist between gut flora, serum metabolites and different cardiac arrhythmias and highlights the need for further exploration. This study provides new perspectives to enhance diagnostic and therapeutic strategies in the field of cardiac arrhythmias.

Association of Atrial Fibrillation with Insomnia in the Elderly Population

INTRODUCTION/OBJECTIVES

Insomnia is a common sleep disorders that affects most individuals in the United States, and worldwide. Insomnia is linked with an increased risk of atrial fibrillation (AF) in adults, although the strengths of association were weak, especially in the elderly population. AF is estimated to affect approximately 3 to 6 million people in the United States. We studied the association of AF with insomnia in the elderly population.

METHODS

We reviewed the electronic medical records of elderly patients who received care in an internal medicine office from July 1, 2020 through June 30, 2021. Patients were grouped into AF group, and a group without AF (NOAF). Association of insomnia and other variables were compared between the 2 groups.

RESULTS

Among 2428 patients, 341 (14%) had AF. Patients in the AF group were significantly older compared to no-AF group (80.3 ± 7.9 vs 76.1 ± 7.4 years; P < .001). A higher frequency of men was noted in AF group versus NOAF group (54.3 vs 42.0%; P < .001). The frequency of insomnia was significantly higher in AF group versus NOAF group (14.1 vs 9.5%; P < .05). Additionally, greater frequencies of associations of other comorbid medical conditions were noted in the AF group compared to NOAF group, such as cerebrovascular accident (CVA; 12.9 vs 5.4%; P < .001), transient ischemic attack (TIA; 7.0 vs 3.0%; P < .001), dementia (5.9 vs 3.3%; P < .05), coronary artery disease (CAD; 34.9 vs 18.3%; P < .001), congestive heart failure (CHF; 21.1 vs 3.8%; P < .001), other cardiac arrhythmias (53.4 vs 6.3%; P < .001), chronic obstructive pulmonary disease (COPD; 12.3 vs 5.7%; P < .001), obstructive sleep apnea (OSA; 17.6 vs 11.8%; P = .003), chronic kidney disease (CKD; 22.9 vs 11.9%; P < .001), anemia (23.2 vs 13.0%; P < .001), and cancer (36.1 vs 27.9%; P = .002). There was significantly greater odds of AF in patients who had insomnia (OR = 1.972, CI = 1.360-2.851; P < .001).

CONCLUSION

AF was associated with insomnia in the elderly population. Higher frequencies of association of AF were also seen with older age, male sex, White race, CVA, TIA, dementia, CAD, CHF, other cardiac arrhythmias, COPD, OSA, CKD, anemia, and cancer.

Epidemiology of atrial fibrillation-related ischemic stroke and its association with DOAC uptake in Spain: first national population-based study 2005 to 2018

INTRODUCTION AND OBJECTIVES

The incidence and prevalence of atrial fibrillation (AF), a major risk factor for stroke, has increased substantially in the past few years. However, several studies have reported a decline in AF-related stroke rates associated with higher uptake of direct oral anticoagulants (DOACs). This ecological study evaluated the association between DOAC uptake in Spain and the incidence rate (IR) of AF-related ischemic stroke.

METHODS

Data were obtained from the Registry of Activity of Specialized Healthcare of the Spanish Ministry of Health (RAE-MDS). AF-related ischemic strokes were identified using International Classification of Diseases codes. IR were age-standardized and adjusted to the 2013 European standard population. Poisson regression models were used to identify the association between DOAC uptake and AF-related ischemic stroke in patients aged ≥ 65 years.

RESULTS

Before the use of DOACs, the adjusted IR of AF-related ischemic stroke increased steadily from 2005 (IR=2.20 per 100 000 person/y) to 2012 (IR=2.67). Upon DOAC uptake in Spain from 2012 onwards for AF-related ischemic stroke prevention, the IR remained constant or decreased slightly (IR in 2018=2.66). Poisson regression showed that DOAC uptake was a significant predictor for the rate of AF-related ischemic stroke in patients older than 65 years (IRR=0.995; 95%CI, 0.995-0.996).

CONCLUSIONS

This study shows an association between DOAC use and a reduced incidence of AF-related ischemic stroke. While this association is based on aggregate data and cannot demonstrate causality, these findings suggest that higher DOAC uptake could improve health outcomes in AF patients in Spain.

Beta-Blocker Landiolol Hydrochloride in Preventing Atrial Fibrillation Following Cardiothoracic Surgery: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this article was to assess the benefit of perioperative administration of the intravenous beta-blocker landiolol hydrochloride in preventing atrial fibrillation (AF) after cardiothoracic surgery.

METHODS

We performed a systematic search in PubMed, Web of Science, CNKI, and OVID to identify randomized controlled trials (RCTs) and cohorts up to January 2021. Data regarding postoperative atrial fibrillation (POAF) and safety outcomes were extracted. Odds ratios (ORs) with 95% confidence intervals (CIs) were determined using the Mantel-Haenszel method. Meanwhile, subgroup analyses were conducted according to surgery type including lung cancer surgery, esophageal cancer surgery, and cardiac surgery.

RESULTS

Seventeen eligible articles involving 1349 patients within 13 RCTs and four cohorts were included in our meta-analysis. Compared with control group, landiolol administration was associated with a significant reduction of the occurrence of AF after cardiothoracic surgery (OR = 0.32, 95% CI 0.23-0.43, P <0.00001). In addition, the results demonstrated that perioperative administration of landiolol hydrochloride minimized the occurrence of postoperative complications (OR = 0.48, 95% CI 0.33-0.70, P = 0.0002). Funnel plots indicated no obvious publication bias.

CONCLUSIONS

Considering this analysis, landiolol was effective in the prevention of AF after cardiothoracic surgery and did not increase the risk of major postoperative complications.

Safety and Efficacy of Left Atrial Appendage Excision Using a Vascular Stapler

Background

This study was conducted to evaluate the safety and efficacy of left atrial appendage (LAA) excision using a vascular stapler.

Methods

Fifty consecutive patients (mean age, 68±9 years) who underwent LAA excision using a vascular stapler during concomitant cardiac surgery were enrolled. In all patients, the excision site was evaluated using computed tomography at a median of 7 days (interquartile range, 5–13.3 days) postoperatively. The safety endpoint of this study was the occurrence of LAA excision-related events, which were defined as bleeding from the excision site that required reinforcement sutures or reoperation due to excision site bleeding. The efficacy endpoint was LAA excision failure, which was defined as a remnant LAA (a stump >1 cm in maximum length) or extravasation of radiocontrast dye.

Results

LAAs were excised using 60- and 45-mm vascular staplers in 49 patients and 1 patient, respectively. Reinforcement sutures were needed in 4 patients due to staple-line bleeding and in 4 patients due to bleeding of the surrounding tissues. No patient underwent reoperation due to staple-related bleeding. A remnant LAA was observed in 2 patients, while extravasation of radiocontrast dye was not observed in any patients.

Conclusion

LAA excision using a vascular stapler may be an effective technique for LAA exclusion. Delicate handling of the stapler device and LA tissue is required to prevent procedure-related complications.

Disparities and Temporal Trends in Stroke Care Outcomes in Patients with Atrial Fibrillation: The FLiPER-AF Stroke Study

Background and Purpose

Atrial Fibrillation (AF) is the most common cardiac cause of ischemic stroke. However, the relation between AF and stroke care outcomes in diverse populations is understudied. We aimed to evaluate sex and race-ethnic disparities associated with AF in hospital stroke outcomes utilizing data from the FLorida PuErto Rico Atrial Fibrillation (FLiPER-AF) Stroke Study.

Methods

The study included 104,308 ischemic stroke cases with available information on AF status enrolled in a state-wide stroke registry from 2010 to 2016. Multivariable logistic regression models were performed to evaluate the association between AF and stroke outcomes and the modification effects on the associations by sex and by race-ethnicity, adjusted for socio-demographic status, vascular risk factors and stroke severity.

Results

AF was present in 23% of ischemic stroke cases. AF was associated with worse disability at discharge (OR=1.11, 95% CI, 1.04-1.18), less discharge to home (OR=0.89, 0.85-0.92), and longer length of hospital stay (LOS>6 days, OR=1.53, 1.46-1.60). Interaction analyses showed that the association between AF and less discharge to home was stronger in women than men (p for interaction <0.001), as well as in FL-whites than in FL-blacks, FL-Hispanics or PR-Hispanics (p for interaction=0.002). The association between AF and prolonged LOS was more prominent in PR-Hispanics than in FL-blacks, FL-Hispanics, or FL-whites (p for interaction <0.001). From 2010 to 2016, the effects of AF on hospital length of stay attenuated (p for interaction<0.001).

Conclusions

AF was associated with poor disability at discharge, less discharge to home, and prolonged hospital length of stay for acute stroke care. The effect of AF on length of stay attenuated over time. Sex and race-ethnic disparities were observed in the effect of AF on being less discharge to home and prolonged hospital stay. Further research is needed to identify and modify the biologic and systems of care contributors to these disparities.

Disparities and Temporal Trends in the Use of Anticoagulation in Patients With Ischemic Stroke and Atrial Fibrillation

Background and Purpose- Ischemic stroke (IS) secondary to atrial fibrillation (AF) is largely preventable with the use of anticoagulation. We sought to identify race-ethnicity and sex disparities with the use of direct oral anticoagulants (DOACs), aspirin, and warfarin in IS patients with AF and to identify temporal trends in the utilization of these medications. Methods- The FLiPER-AF Stroke Study (Florida Puerto Rico Atrial Fibrillation) included 24 040 IS cases enrolled in the Florida-Puerto Rico Collaboration to Reduce Stroke Registry from 2010 to 2016. Multivariable logistic regression models were performed to evaluate the effect of race-ethnicity and sex on utilization of DOACs, aspirin, and warfarin for stroke prevention in AF after adjustment for sociodemographic, hospital, and clinical factors. Results- Among 24 040 IS cases, 54% were women and 10% black, 12% FL-Hispanics, 4% PR-Hispanic, and 74% whites. From 2010 to 2016, DOAC use increased from 0% to 36%, warfarin use decreased from 51% to 17%, and aspirin use remained relatively stable (42%-40%). After adjustment, blacks had higher odds of warfarin (odds ratio, 1.22; 95% CI, 1.07-1.40) prescription at discharge compared with whites. Men had higher rates of aspirin (42.1% versus 38.8%), warfarin (33.6% versus 28.9%), and DOAC (21.3% versus 19.3%) use compared with women. After adjustment, women had lower odds of being discharged on aspirin (odds ratio, 0.92; 95% CI, 0.86-0.98) or warfarin (odds ratio, 0.91; 95% CI, 0.84-0.99). There was no sex difference in use of DOACs. Conclusions- Our study confirmed the increasing use of DOACs, downtrending use of warfarin, whereas aspirin use remained similar over the years. There are sex and race-ethnicity disparities in anticoagulation use in IS patients with AF. It is critical to understand underlying drivers of these disparities to develop better practice strategies for stroke prevention in patients with AF. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT03627806.

Addressing Multimorbidity and Polypharmacy in Individuals With Atrial Fibrillation

PURPOSE OF REVIEW

The objectives of this review were to (1) discuss how multimorbidity and polypharmacy contributes to the complexity of management among individuals with AF and (2) identify any interventions to manage polypharmacy in relation to AF.

RECENT FINDINGS

Based on the four landmark clinical trials of novel anticoagulants, the most common comorbidities with AF are hypertension, heart failure, diabetes, stroke and myocardial infarction. Polypharmacy was also found prevalent in 76.5% of patients with AF, with a median of six drugs per patient. Despite the consequences of polypharmacy in AF, there is very little evidence-based intervention designed to manage it. Hence, there is a need for further research to examine interventions to manage polypharmacy in relation to AF. Atrial fibrillation (AF) is the most common type of cardiac arrhythmia requiring treatment in adults. Due to the structural and/or electrophysiological abnormalities that occur in AF, patients are managed through the use of prophylactic anticoagulant and rate and/or rhythm control medications. However, these medications are considered high risk and can increase the chances of medication misadventure. Additionally, AF rarely occurs in isolation and is known to coexist with multiple other medical comorbidities, i.e. multimorbidity. This also increases the number of medications, i.e. polypharmacy and pill burden which results in treatment non-compliance to prescribed therapy.

Atrial Strain and Strain Rate: A Novel Method for the Evaluation of Atrial Stunning

Background

Atrial fibrillation (AF) is the most common arrhythmia seen in adults. Atrial stunning is defined as the temporary mechanical dysfunction of the atrial appendage developing after AF has returned to sinus rhythm (SR).

Objectives

We aimed to evaluate atrial contractile functions by strain and strain rate in patients with AF, following pharmacological and electrical cardioversion and to compare it with conventional methods.

Methods

This study included 41 patients with persistent AF and 35 age-matched control cases with SR. All the AF patients included in the study had transthoracic and transesophageal echocardiography performed before and after. Septum (SEPsSR), left atrium (LAsSR) and right atrium peak systolic strain rate (RAsSR) were defined as the maximum negative value during atrial contraction and septum (SEPε), left atrium (LAε) and right atrium peak systolic strain (RAε) was defined as the percentage of change. Parameters of two groups were compared.

Results

In the AF group, 1st hour and 24th hour LAε, RAε, SEPε, LAsSR, RAsSR, SEPsSR found to be significantly lower than in the control group (LAε: 2.61%±0.13, 3.06%±0.19 vs 6.45%±0.27, p<0.0001; RAε: 4.03%±0.38, 4.50%±0.47 vs 10.12%±0.64, p<0.0001; SEPε: 3.0%±0.22, 3.19%±0.15 vs 6.23%±0.49, p<0.0001; LAsSR: 0.61±0.04s-¹, 0.75±0.04s-¹ vs 1.35±0.04s-¹, p<0.0001; RAsSR: 1.13±0.06s-¹, 1.23±0.07s-¹ vs 2.10±0.08s- ¹, p<0.0001; SEPsSR: 0.76±0.04s- ¹, 0.78±0.04s- ¹ vs 1.42±0.06 s- ¹, p<0.0001).

Conclusion

Atrial strain and strain rate parameters are superior to conventional echocardiographic parameters for the evaluation of atrial stunning in AF cases where SR has been achieved.

Predictors of Atrial Fibrillation Recurrence in Hyperthyroid and Euthyroid Patients

BACKGROUND

Atrial fibrillation (AF) is the most common arrhythmia in adults, and is encountered in 10-15% of the patients with hyperthyroidism. Unless euthyroidism is restored, pharmacological or electrical cardioversion is controversial in patients with AF who remain hyperthyroid.

OBJECTIVE

The aim of this study was to assess the efficacy of electrical cardioversion and predictors of AF recurrence in hyperthyroid and euthyroid patients.

METHODS

The study included 33 hyperthyroid (21 males) and 48 euthyroid (17 males) patients with persistent AF. The patients were sedated with intravenous midazolam before undergoing electrical cardioversion delivered by synchronized biphasic shocks. Rates of AF recurrence were recorded.

RESULTS

Mean follow-up was 23.63 ± 3.74 months in the hyperthyroid group and 22.78 ± 3.15 months in the euthyroid group (p = 0.51). AF recurred in 14 (43.8%) and 21 (44.7%) patients in each group, respectively (p = 0.93). Multivariate regression analysis in each group showed that AF duration was the only predictor of AF recurrence, with odds ratios of 1.38 (95% confidence interval [CI] = 1.05 - 1.82, p = 0.02) in the hyperthyroid group and 1.42 (95% CI = 1.05 - 1.91, p= 0.02) in the euthyroid group.

CONCLUSION

Rates of long-term AF recurrence were similar in successfully cardioverted hyperthyroid and euthyroid patients. The only predictor of AF recurrence in both groups was AF duration.

Predictors of Ischemic Stroke in Rheumatic Heart Disease

BACKGROUND

Studies on predictors of ischemic strokes caused by rheumatic heart disease (RHD) are sparse and extremely important for identifying high-risk cases to direct future therapeutic trials for prevention of ischemic stroke in this population.

OBJECTIVE

The aim of the present study was to study the predictors of ischemic stroke in patients with RHD and to observe outcome of patients with ischemic stroke at 3 months' follow-up using modified Rankin scale.

METHODS

We conducted a case-control study comparing the clinical profile of 40 adult patients with acute ischemic stroke caused by RHD with equal numbers of matched controls comprising patients with RHD without any prior history of stroke. We also observed the functional outcome of ischemic strokes in these patients.

RESULTS

The presence of left atrial spontaneous echo contrast (odds ratio = 39.9; 95% confidence interval, 3.16-501.9; P = .004) and atrial fibrillation (AF) (odds ratio = 3.2; 95% confidence interval, 1.6-6.7; P = .002) was significantly associated with stroke occurrence in RHD populations. The outcome of patients was good with low mortality and significant improvement of modified Rankin scale at 3 months' follow-up.

CONCLUSIONS

Presence of AF and left atrial spontaneous echo contrast are significant risk factors for ischemic stroke in patients with RHD. There is high percentage of subclinical AF in this population. Future large clinical trials for oral anticoagulation/antiplatelet agents are needed for stroke prevention in high-risk RHD patients identified by a detailed workup.

Prediction of recurrence after cryoballoon ablation therapy in patients with paroxysmal atrial fibrillation

OBJECTIVE

The purpose of this study was to investigate the factors predicting the maintenance of sinus rhythm in patients with paroxysmal atrial fibrillation (PAF) who underwent cryoablation of the pulmonary veins (PVs).

METHODS

Fifty-one patients (54.6±10.4 years) with paroxysmal AF who underwent the cryoablation of the PVs were to the prospective trial. The clinical risk factors and echocardiographic parameters [left atrial (LA) diameter, left ventricular ejection fraction and dimensions, left atrial spontaneous echo contrast (LASEC), mitral annulus calcification (MAC), left atrial appendage emptying peak flow velocity (LAAV), and PV flow] were assessed before the cryoablation procedure. Patients with PAF who refused to use any medication because of intolerance or presentation of resistant symptoms, despite the use of at least one antiarrhythmic drug were enrolled to the study, patients with LA/LAA thrombus on echocardiographic examination, severe valvular disease, pericardial fluid, and abnormal thyroid function tests as well as systemic disease were excluded from the study. All parameters were tested for their ability to predict the recurrence of AF during a 1-year follow-up period.

RESULTS

During the period of follow-up, AF recurred in 16 of 51 patients (31.3%/year). All significant parameters associated with the recurrence of AF were evaluated in multivariate logistic regression analysis. The presence of MAC (p<0.001) as well as LA diameter (p<0.0001), LAAV of <30 cm/s (p<0.0001), PV flow systolic wave velocity (p<0.0001), and LASEC (p<0.0001) were detected as independent predictors of recurrence. In the receiver operating characteristic analysis, LAAV of >30 cm/s had a sensitivity of 85% and a specificity of 95% for predicting success after ablation (AUC=0.813; 95% CI: 0.76-0.92; p<0.0001).

CONCLUSION

The presence of MAC, increased LA diameter, the existence of LASEC, low LAAV, and low peak PV systolic wave velocity are parameters that can predict the recurrence of AF after cryoablation.

Bilateral Internal Thoracic Artery Grafting: Is It Reasonable in Octogenarians?

PURPOSE

The feasibility of using bilateral internal thoracic artery (BITA) grafts for coronary artery bypass grafting (CABG) in octogenarians is not clear. This study aimed to compare outcomes between use of BITA and single internal thoracic artery (SITA) grafts in octogenarians undergoing isolated CABG.

METHODS

Isolated CABG was performed in 1,566 patients at the Sakakibara Heart Institute between September 2004 and December 2012. Of these, 125 consecutive octogenarians were included and divided into two groups, according to the use of BITA grafts (101 subjects) or SITA grafts (24 subjects). Early and late outcomes were compared between groups.

RESULTS

The preoperative patient characteristics were similar between the two groups. Early outcomes were similar, including hospital death or deep sternal infection. The estimated 5-year survival rate was similar in the BITA and SITA groups (78% vs 62%, p = 0.269). Freedom from major adverse cardiac or cerebrovascular events was significantly higher in the BITA group than in the SITA group after 5 years (90% vs 75%, p = 0.032).

CONCLUSIONS

Our results suggest that use of BITA grafts for CABG is feasible and beneficial in octogenarians, resulting in improved late outcomes without increased operative risk.

Incidence of stroke and acute renal failure in patients of postoperative atrial fibrillation after myocardial revascularization

Introduction

Postoperative atrial fibrillation is the most common arrhythmia in cardiac surgery, its incidence range between 20% and 40%.

Objective

Quantify the occurrence of stroke and acute renal insufficiency after myocardial revascularization surgery in patients who had atrial fibrillation postoperatively.

Methods

Cohort longitudinal bidirectional study, performed at Portuguese Beneficent Hospital (SP), with medical chart survey of patients undergoing myocardial revascularization surgery between June 2009 to July 2010. From a total of 3010 patients were weaned 382 patients that presented atrial fibrillation preoperatively and/or associated surgeries. The study was conducted in accordance with national and international following resolutions: ICH Harmonized Tripartite Guidelines for Good Clinical Practice - 1996; CNS196/96 Resolution, and Declaration of Helsinki.

Results

The 2628 patients included in this study were divided into two groups: Group I, who didn't show postoperative atrial fibrillation, with 2302 (87.6%) patients; and group II, with 326 (12.4%) who developed postoperative atrial fibrillation. The incidence of stroke in patients was 1.1% without postoperative atrial fibrillation vs. 4% with postoperative atrial fibrillation (P<0.001). Postoperative acute renal failure was observed in 12% of patients with postoperative atrial fibrillation and 2.4% in the group without postoperative atrial fibrillation (P<0.001), that is a relation 5 times greater.

Conclusion

In this study there was a high incidence of stroke and acute renal failure in patients with postoperative atrial fibrillation, with rates higher than those reported in the literature.

Efficacy of Cox Maze IV Procedure Using Argon-Based Cryoablation: A Comparative Study with N2O-Based Cryoablation

BACKGROUND

We compared the mid-term results of the Cox maze IV procedure using argon-based cryoablation with a procedure using N2O-based cryoablation.

METHODS

From May 2006 to June 2012, 138 patients (mean age, 58.2±11.0 years) underwent the Cox maze IV procedure. Eighty-five patients underwent the maze procedure using an N2O-based cryoprobe (group N), and 53 patients underwent the maze procedure using an argon-based cryoprobe (group A). Bipolar radiofrequency ablation was concomitantly used in 131 patients. The presence of atrial fibrillation immediately, 6 months, 1 year, and 2 years after surgery was compared.

RESULTS

Early mortality occurred in 6 patients (4.3%). There were no differences in early mortality or postoperative complications between the two groups. Nineteen of 115 patients (16.5%) remained in atrial fibrillation at postoperative 12 months (14 of 80 patients (17.5%) in group N and 5 of 35 patients (14.3%) in group A, p=0.669). There were no differences in the number of patients who remained in atrial fibrillation at any of the time periods except in the immediate postoperative period. A multivariable analysis revealed that the energy source of cryoablation was not associated with the presence of atrial fibrillation at 1 year (p=0.862) and that a fine F wave (<0.1 mV) was the only risk factor predicting the presence of atrial fibrillation at 1 year (p<0.001, odds ratio=20.287).

CONCLUSION

The Cox maze IV procedure using an argon-based cryoprobe was safe and effective compared with the maze procedure using an N2O-based cryoprobe in terms of operative outcomes and the restoration of sinus rhythm for up to 2 years after surgery.

Focal Impulse And Rotor Mapping (FIRM): Conceptualizing And Treating Atrial Fibrillation

Current approaches for the ablation of atrial fibrillation are often effective, but only partially rooted in mechanistic understanding. Accordingly, they are unable to predict whether a given patient will or will not do well, or which lesions sets should or should not be performed - in any given patient. This goal would require clearer mechanistic definition of what sustains AF after it has been triggered (i.e. electrophysiological substrates). There are two schools of thought. The first proposes disorganized activity that self-sustains with no 'driver', and the second describes drivers that then cause disorganization. Interestingly, these mechanisms can be separated in human studies by mapping approach - proponents of the disorganized hypothesis studying small atrial areas at high resolution, and proponents of the driver model studying wide fields-of-view at varying resolutions. Focal impulse and rotor modulation (FIRM) mapping combines a wide field of view with physiologically based signal filtering and phase analysis, and has revealed that human AF is often sustained by rotors. In the CONFIRM Trial, targeting stable AF rotors/sources for ablation improved the single-procedure efficacy for paroxysmal and persistent AF over conventional ablation alone, as now confirmed by independent laboratories. FIRM mapping gives a mechanistic foundation to predict whether any selected lesions should intersect AF sources in any given patient and which mechanisms may cause recurrence. Rotors of varying characteristics have now been shown by many groups. These insights have reinvigorated interest in AF mapping, and rationalizing these findings will likely translate into improved therapy for our patients.

Treatment patterns associated with stroke prevention in patients with atrial fibrillation in three major cities in the People's Republic of china

BACKGROUND

Atrial fibrillation (AF) is associated with an increased risk of stroke. This study assessed treatment patterns associated with stroke prevention among patients with AF in three major cities of the People's Republic of China.

METHODS

A random sample of 2,862 medical charts for patients with AF at six tertiary hospitals located in Beijing, Shanghai, and Guangzhou between 2003 and 2008 were reviewed. Patient demographics, clinical characteristics, and treatment patterns were extracted from medical charts. Antithrombotic regimens included antiplatelets, anticoagulants, and a combination of both. Descriptive analyses were performed to summarize basic antithrombotic patterns. A logistic regression model examined demographic and clinical factors associated with antithrombotic treatment patterns.

RESULTS

Of the patient sample, 55% were male, the average age was 72 years (49% ≥75 years), 15% had valvular AF, 78% had nonvalvular AF, and the remainder had unspecified AF. CHADS2 scores ≥2 were reported for 53% of patients. Antithrombotic treatment was not received by 17% of patients during hospitalization, and 66% did not receive warfarin. Among patients with valvular or nonvalvular AF, 33%, 30%, and 20% received antiplatelet, anticoagulation, and antiplatelet plus anticoagulation treatments, respectively. For patients with CHADS2 scores of 0, 1, 2, 3, and ≥4, 52%, 42%, 28%, 21%, and 21%, respectively, were treated with warfarin. Predictors of no antithrombotic treatment included age and hospital location.

CONCLUSION

Anticoagulation therapy was underused in Chinese patients with AF. Antithrombotic treatment was not associated with stroke risk. Further studies need to examine the clinical consequences of various antithrombotic treatment patterns in Chinese patients with AF.

Atrial fibrillation in aortic stenosis--echocardiographic assessment and prognostic importance

Background

Atrial fibrillation (AFib) exists more frequently in patients with aortic stenosis (AS) than in patients without, and AFib may be a sign of progressive deterioration of AS. Echocardiographic assessment of AS in sinus rhythm is well documented, however, little is known about AFib in AS since such patients often are excluded from clinical echocardiographic trials.

Aim

The purpose of this study was to assess the prognostic importance of AFib in AS.

Methods

The study was designed as a single-center case-control study. Patients with AS and AFib were enrolled as cases (n = 103) and subsequently matched to controls (103 patients with AS but sinus rhythm). Cases and controls were matched according to age, gender and severity of AS. Primary outcome was all cause mortality and follow-up was 100% complete.

Results

Compared to controls the group with AFib had lower mean ejection fraction (42% vs. 49%; p < 0.001) and stroke volume (47 mL vs. 55 mL; p = 0.004), but higher heart rate (81 bpm vs. 68 bpm; p < 0.001) and no significant difference with regard to cardiac output (3.8 L vs. 4.0 L; p = 0.29). Accordingly, aortic jet velocity and gradients were significantly lower in AFib compared to controls but there were no differences (p = 0.38) in aortic valve area calculated by the continuity equation. During a median follow-up of 2.3 years (IQR: 1.2-3.6), 70 (34%) patients with AS died: 42 patients with AFib and 28 patients with sinus rhythm (p < 0.02). After adjusting for echocardiographic significant differences, AFib remained an independent predictor of mortality (HR 2.72 (95% CI: 1.12–6.61), p < 0.03). There was no significant interaction (p = 0.62) between AFib and AS on the risk of mortality, indicating that AFib predicted bad outcome regardless of the severity of AS.

Conclusions

AFib is an independent risk factor in patients with AS and the prognostic impact of AFib seems to be the same despite the severity of AS.

A randomized comparison of amiodarone and class IC antiarrhythmic drugs to treat atrial fibrillation in patients paced for sinus node disease: the Prevention Investigation and Treatment: A Group for Observation and Research on Atrial arrhythmias (PITAGORA) trial

BACKGROUND

Rhythm control is an important goal in the treatment of recurrent atrial tachyarrhythmias (AT). The PITAGORA study was a randomized trial in patients paced for sinus node disease (SND), designed to test the noninferiority of class IC antiarrhythmic drugs (AADs) to amiodarone in terms of a primary end point composed of death, permanent AT, cardiovascular hospitalization, atrial cardioversion, or AAD change.

METHODS

Randomization was stratified to assign 2 patients to amiodarone and 2 patients to class IC AADs: propafenone or flecainide. One hundred seventy-six patients (46% men, 72 +/- 8 years) were enrolled. Device diagnostics continuously monitored AT recurrences and duration.

RESULTS

In a mean follow-up of 20 +/- 9 months, the primary end point occurred in 23 (30.7%) of 75 class IC patients and in 28 (40.0%) of 70 amiodarone patients. The absolute difference in the end point incidence (-9.3%; 95% CI between 3.7% and -22.3%) confirmed the noninferiority of class IC to amiodarone (P = .007). Kaplan-Meier 1-year freedom from AT episodes >10 minutes, 1 day, and 7 days was 40%, 73%, and 91% for amiodarone and 28%, 78%, and 86% for class IC AADs (P = nonsignificant).

CONCLUSIONS

In patients paced for SND and suffering from AT, class IC AADs proved not to be inferior to amiodarone in terms of the primary composite end point described or end points which were differently composed of mortality, efficacy, or AAD side effects. The AADs studied also showed similar results in terms of symptoms, quality of life, and freedom from AT recurrences.

Current strategies in the surgical treatment of atrial fibrillation: review of the literature and Onze Lieve Vrouw Clinic's strategy

Atrial fibrillation is the most common rhythm disturbance in clinical practice. It is a major source of stroke and morbidity. Although the Cox maze procedure effectively eliminates atrial fibrillation in most patients, the procedure has not found widespread application. As a consequence, new operations that use alternative sources of energy, such as radiofrequency, microwave, cryothermy, laser, and ultrasound have emerged to surgically create lesion sets to treat atrial fibrillation. This article reviews the fundamentals and current strategies in the surgical treatment of atrial fibrillation.

Gemcitabine and atrial fibrillation: a rare manifestation of chemotherapy toxicity

Gemcitabine is a purine analog with known activity in many solid tumors, namely lung, breast, pancreatic, genitourinary and head/neck cancers. Cardiac toxicity is a rare event and only one report previously described atrial fibrillation (AF) as a consequence of gemcitabine infusion. We report two cases of women suffering from lung cancer who were treated with gemcitabine. Both patients were admitted to hospital for paroxysmal AF occurring 12-24 h after the infusion of the drug. In the first case a sinus rhythm was spontaneously repristinated when AF occurred for the first time, while the second episode required an anti-arrhythmic drug to interrupt the dysrhythmia. In the second case, the patient had to be treated with digitalis glycoside to control the ventricular response without attaining a sinus rhythm. We could not recognize any other precipitating factor beyond the infusion of gemcitabine as a cause for the arrhythmia. Both cases were treated with gemcitabine for lung cancer and we observed the appearance of AF less than 24 h after drug administration. We assume that 2',2'-difluorodeoxyuridine, an active metabolite of gemcitabine, could be responsible for the toxic effect. We conclude that AF is an unusual, but potentially dangerous, side-effect of gemcitabine infusion. The arrhythmia should be suspected whenever patients complain of dyspnea and palpitations beginning 12-24 h after treatment. In these cases, the treatment of AF consists of anti-arrhythmic drugs in order to repristinate a sinus rhythm or control the heart rate.

Design and rationale of a randomized study to compare amiodarone and Class IC anti-arrhythmic drugs in terms of atrial fibrillation treatment efficacy in patients paced for sinus node disease: the PITAGORA trial

AIMS

Many sinus node disease (SND) patients suffer from atrial fibrillation (AF). Anti-arrhythmic drugs (AADs) are the therapeutic mainstay for AF prophylaxis. The PITAGORA trial has a multicentre, prospective, randomized, single blind design to compare amiodarone with Class IC AADs in patients who have an AF history and are paced for SND.

METHODS AND RESULTS

Starting from January 2001, 176 patients received a Medtronic AT500 pacemaker. AADs were randomly assigned with a 3 : 2 ratio between Class III and Class IC. Randomization was stratified in order to assign two patients to amiodarone and one patient to sotalol every three Class III AAD patients. After a 5-month observational period, Ramp or Burst+ ATP therapies were enabled in a randomized way, maintained for 4 months, and then crossed over. Total follow-up period is 21 months. The primary long-term objective is to show the non-inferiority of IC AADs compared with amiodarone in terms of time to first occurrence of a composite endpoint (death, atrial cardioversion, hospitalizations due to AF or heart failure, or change of AADs). Data will be analysed on an intention-to-treat basis. The primary short-term objective is to compare Ramp vs. Burst+ efficacy in terminating atrial tachyarrhythmias treated by the device. Secondary endpoints are major clinical events, medication toxicity, symptoms, AF burden, and quality-of-life.

CONCLUSION

Given the high morbidity and healthcare costs associated with AF, new therapeutic strategies are needed. The results of the PITAGORA trial may help in guiding AADs therapy and ATP programming in SND patients suffering from AF.

Hybrid Therapy with Right Atrial Catheter Ablation and Previously Ineffective Antiarrhythmic Drugs for the Management of Atrial Fibrillation

BACKGROUND

Many patients with paroxysmal atrial fibrillation (AF) become refractory to antiarrhythmic drugs (AADs). Early studies suggested that linear catheter ablation in the right atrium may provide sufficient substrate modification to reestablish therapeutic efficacy of previously ineffective AADs.

METHODS

This prospective before-after multicenter trial evaluated the safety and effectiveness of hybrid therapy that included right atrial catheter ablation coupled with a regimen of previously ineffective AADs on AF episode frequency and symptoms in drug refractory patients with paroxysmal AF. A standard linear lesion set (lateral, septal, isthmus) was used in all subjects. AF episode frequency, clinical arrhythmia symptoms, condition-specific (AFSS) and global health-related quality of life (SF-36) were assessed prior to ablation and at 6 months.

RESULTS

Ninety-three subjects, refractory to an average 2.9 AADs at baseline, qualified for inclusion and underwent right atrial catheter ablation. Eighty-four subjects (90%) provided 6 month AF episode frequency data which demonstrated a significant decrease compared to baseline (3.4 vs. 9.5, p < 0.0001). Forty-nine subjects (58%) were considered a clinical success by virtue of achieving a pre-specified target level episode frequency reduction of 50% or greater. Substantial and statistically significant improvements were realized almost uniformly for all measured arrhythmia symptoms as well as for both quality of life measures. The incidence of major complications was 5.4%.

CONCLUSIONS

The addition of right atrial catheter ablation to a regimen of previously ineffective AADs is associated with a significant reduction in the frequency, duration and severity of AF episodes and symptoms.

Are Cost Benefits of Anticoagulation for Stroke Prevention in Atrial Fibrillation Underestimated?

BACKGROUND AND PURPOSE

Stroke outcomes in patients with atrial fibrillation (AF) tend to be worse than those in patients without AF. The objective of this study was to evaluate whether the cost benefits of anticoagulation for stroke prevention in AF may currently be underestimated by existing economic models that do not distinguish between different stroke outcomes.

METHODS

A literature review was conducted in 3 areas: (1) studies comparing stroke outcomes in AF and non-AF patients; (2) studies providing long-term cost of stroke estimates; and (3) studies modeling the cost-effectiveness of anticoagulation with a vitamin K antagonist (eg, warfarin) in AF patients.

RESULTS

There is considerable evidence that stroke in AF patients has a worse outcome than in patients without AF, including higher mortality, severity, and recurrence rates, and greater functional impairment and dependency. Estimates of the long-term cost of stroke of different severities were between US 24,991 dollars for a mild stroke over 5 years and US 142,251 dollars for a major ischemic stroke over a lifetime (2004 prices). The cost of a severe ischemic stroke may typically be 3-times that of mild stroke. However, cost-effectiveness models for anticoagulation in patients with AF have used average (not AF-specific) cost-of-stroke data, and most have used stroke severity distributions derived from clinical trials, which may differ from those in clinical practice.

CONCLUSIONS

Existing economic models underestimate the cost benefits of anticoagulation for stroke prevention because they do not adjust for poorer outcomes associated with cardioembolic strokes.

Surgical Treatment of Atrial Fibrillation

This article reviews the fundamentals of surgical treatment of atrial fibrillation. The clinical classification, pathophysiology, medical treatment strategy, and catheter-based interventions are also included. The Cox-Maze III procedure was developed over based on experiences of several operations which proceeded it. The operation is complex but results are excellent with over 90% of patients in normal sinus rhythm or regular atrial rhythm. Several modifications have been devised using various energies to ablate atrial myocardium as a means of extending surgical incisions to simplify the Maze III operation. Techniques and results of these operations are reviewed. Modified operations offering about 80% restoration of sinus rhythm are attractive to more surgeons because of the reduced complexity and time of operation.

Treating Atrial Fibrillation

Atrial fibrillation (AF), a rhythm characterized by disorganized depolarization of the atria, is frequently encountered in the clinical setting. This dysrhythmia significantly impacts hemodynamics, exercise tolerance, and quality of life. Many factors contribute to this complex dysrhythmia, ultimately leading to electrical and mechanical remodeling. Rhythm control has been the initial treatment choice for AF. However, until recently, differences in outcomes associated with rhythm control versus rate control for AF were unknown. Data from recent clinical trials suggest that rate control is equivalent to rhythm control in terms of mortality. In the rhythm-control group compared to the rate-control group, there was a tendency for increased hospitalizations and medication reactions (although these differences were not significant). Anticoagulation remains an important component of therapy when treating AF, but continues be to inadequately prescribed. Further, INRs commonly are not maintained in a therapeutic range. Finally, the results of the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM), Pharmacological Intervention in Atrial Fibrillation (PIAF), and the Comparison of Rate Control and Rhythm Control in Patients with Recurrent Persistent Atrial Fibrillation (RACE) trials provide guidance in treatment strategies for AF.

Atrial fibrillation after esophagectomy is a marker for postoperative morbidity and mortality

OBJECTIVE

Postoperative atrial fibrillation complicates recovery in 20% to 25% of patients after esophagectomy for cancer. The purpose of this study is to understand this phenomenon.

METHODS

Between 1982 and 2000, 198 (22% of 921) patients had postoperative atrial fibrillation after esophagectomy. Propensity scoring and the Greedy Match algorithm were used to develop a cohort of control patients for statistical comparisons. One hundred forty-four patients who had postoperative atrial fibrillation were matched.

RESULTS

Pulmonary complications affected 42% of patients in the atrial fibrillation group compared with 17% in the control group (P <.001). Anastomotic leakage was more common in the atrial fibrillation group (6.9% vs 1.4%, P =.035). Surgical sepsis migrated with atrial fibrillation 4 times more frequently (P =.001). Multivariate analysis demonstrated that postoperative pulmonary complications (odds ratio, 2.5; 95% confidence interval, 1.42-4.3) and surgical sepsis (odds ratio, 3.4; 95% confidence interval, 1.2-9.6) were associated with postoperative atrial fibrillation. The mortality rates of the atrial fibrillation and control groups were 23% and 6.3%, respectively (P <.001). Median survival, excluding hospital deaths, was not different at 14.5 months (atrial fibrillation group) and 16.9 months (control group; P =.4).

CONCLUSION

Atrial fibrillation is a surrogate for surgical morbidity and mortality after esophagectomy. The occurrence of atrial fibrillation after esophageal resection should prompt not only the appropriate management of the arrhythmia but also a search for a more ominous underlying cause.

Is beta-blockade useful in heart failure patients with atrial fibrillation? An analysis of data from two previously completed prospective trials

BACKGROUND

Beta-adrenergic blockade is of proven value in chronic heart failure. It is uncertain, however, if beta-blockade provides a similar degree of clinical benefit for heart failure patients with atrial fibrillation (AF) as those in sinus rhythm (SR).

AIMS

To compare the effectiveness of beta blockade in patients with heart failure and AF.

METHODS

Patients with chronic heart failure were randomized to treatment (double blind) with metoprolol 50 mg twice daily or carvedilol 25 mg twice daily in addition to standard therapy. Response was assessed after 12 weeks by a quality of life questionnaire, New York Heart Association class, exercise capacity (6-min walk test), radionucleotide ventriculography for LVEF, 2-D echocardiography measurement of left ventricular (LV) dimensions and diastolic filling and 24-h electrocardiograph monitoring to assess heart rate changes.

RESULTS

Both beta-blockers produced significant improvements in LVEF in both the SR group: (+6+/-10% at 12-week, P<0.001) and the AF group: (+11+/-9% at 12-week, P<0.05). However, significant improvement in symptoms (P<0.001) and exercise capacity (P<0.001) were observed only in the SR group but not in the AF group despite a significant improvement in LVEF.

CONCLUSION

Beta-blockers were effective in improving LV ejection fraction in chronic heart failure patients in either SR or AF but had less effect on symptoms and exercise capacity in those with AF.

Circadian rhythm of atrioventricular conduction predicts long-term survival in patients with chronic atrial fibrillation

The R-R interval of the electrocardiogram during atrial fibrillation (AF) appears absolutely irregular. However, the Poincaré plot of the R-R interval reveals a sector shape of distribution that is unique to AF. Furthermore, the height of lower envelope (LE1.0) of the distribution and the degree of scatter above the envelope (scattering index) may reflect the refractoriness and concealment of atrioventricular (AV) conduction, respectively. We previously observed that both the LE1.0 and scattering index show clear circadian rhythms in patients with chronic AF and that the rhythms are blunted in those with congestive heart failure and chronic AF. In the present study, we examined if the blunted circadian rhythm of the AV conduction has prognostic value in patients with chronic AF. We studied a retrospective cohort of 120 patients who underwent 24h Holter monitoring at baseline. During an observation period of 33 +/- 16 mon, there were 25 deaths (21%) including 13 cardiac and 8 stroke deaths. All patients showed significant circadian rhythms in both LE1.0 and scattering index with acrophases occurring at night; however, patients dying subsequently from cardiac causes, but not those from fatal stroke were blunted in the circadian rhythms (the amplitudes were < 55% of those in surviving patients). Furthermore, the reduced circadian amplitude of scattering index was an increased risk for cardiac death even after adjustment of coexisting cardiovascular risks [adjusted relative risk (95% confidence interval) per 1-SD decrement, 4.24 (1.54-11.6)]. When patients were divided by the circadian amplitude of the scattering index of 36.5 msec (mean minus 1-SD), the 5yr cardiac mortality below and above the cutoff was 57 and 6%, respectively (log-rank test, p < 0.001). We conclude that the blunted circadian rhythm of AV conduction is an independent risk for cardiac death in patients with chronic AF.

An emergency department observation unit protocol for acute-onset atrial fibrillation is feasible

STUDY OBJECTIVE

We sought to describe the feasibility of an emergency department observation unit (EDOU) treatment protocol for the management of uncomplicated acute-onset atrial fibrillation (AAF).

METHODS

This descriptive case series took place at a major suburban, university-affiliated teaching hospital. Patients were prospectively enrolled in an EDOU treatment protocol if they had uncomplicated AAF that failed initial ED attempts to convert to sinus rhythm. In the EDOU, patients underwent ECG monitoring, serial creatine kianse MB measurements, and further rate control with optional electrical cardioversion. Primary outcomes measured were EDOU rate of conversion to sinus rhythm, rate of discharge home, length of stay, positive diagnostic outcomes, complications of AAF, and 7-day return visits.

RESULTS

Sixty-seven patients were studied. Patients were symptomatic for a median of 4.0 hours, had mean initial ED pulse rates of 137+/-23 beats/min, and spent 4.7+/-2.2 hours in the ED before transfer to the EDOU. While in the EDOU, 55 (82%) patients converted to sinus rhythm. Five (7%) patients were admitted because of positive test results: 2 for myocardial infarction, 2 for fever, and 1 for ventricular tachycardia. Twelve (18%) patients remained in atrial fibrillation, with 9 admitted and 3 discharged. Overall, 81% of patients were discharged in 11.8+/-7.0 hours, and 19% were admitted after 17.6+/-9.5 hours of observation. Three discharged patients returned within 7 days, 2 for uncomplicated recurrent AAF and 1 for chest pain subsequently found to be noncardiac in origin. There were no major complications attributable to the EDOU protocol.

CONCLUSION

Selected patients with AAF for whom initial ED management fails can subsequently be managed in an EDOU with a high short-term conversion and discharge rate.

Does recombinant human interleukin-11 exert direct electrophysiologic effects on single human atrial myocytes?

Recombinant human interleukin-11 (rhIL-11) treatment given to alleviate side effects of cancer therapy is associated with an increased susceptibility to atrial arrhythmias in elderly patients. To elucidate the mechanism underlying this action, we investigated the direct electrophysiologic effect of rhIL-11 on single human atrial myocytes (HuAM) using the patch-clamp technique. Action potentials (AP) at different driving rates were recorded in the perforated-patch configuration, and L-type calcium current (I(Ca,L)), outward potassium currents (I(to) and I(K)), and the hyperpolarization-activated pacemaker current If were measured in the disrupted whole-cell configuration. At therapeutic concentrations (i.e., 10-100 ng/ml), rhIL-11 did not modify AP parameters and cycle-length dependence of AP duration. I(Ca,L) (measured at 0 mV) was 370 +/- 45 pA in control and 379 +/- 48 pA and 368 +/- 42 pA in the presence of 10 and 50 ng/ml rhIL-11, respectively (p = NS). The amplitude and activation of I(to) were not modified by rhIL-11 (i.e., I(to) was at +60 mV: 2.1 +/- 0.2 nA in control vs. 1.9 +/- 0.2 nA and 2.1 +/- 0.2 nA in the presence of 10 and 50 ng/ml rhIL-11, respectively, p = NS). Similarly, late currents measured at the end of the pulse were unchanged in the presence of 10 or 50 ng/ml of rhIL-11. If activation was not modified by rhIL-11: maximal current was 173 +/- 34 pA in control and 159 +/- 35 pA and 117 +/- 14 pA in the presence of 10 and 50 ng/ml of rhIL-11, respectively; midpoint activation was -99 +/- 3 mV in control and -98 +/- 4 mV and -94 +/- 2 mV in the presence of 10 and 50 ng/ml of rhIL-11, respectively (p = NS). Thus, it is unlikely that direct alterations of membrane potential and currents of HuAM caused by rhIL-11 are the basis for the genesis of atrial arrhythmias observed in patients treated with this agent.

Atrial fibrillation: strategies to control, combat, and cure

Atrial fibrillation is the commonest clinical arrhythmia, is increasing in incidence and prevalence, and is associated with substantial morbidity and mortality. The arrhythmia may be paroxysmal (self-limiting), persistent (amenable to cardioversion), or permanent. Especially in its paroxysmal form, atrial fibrillation may be initiated by rapidly firing foci, generally located in the proximal pulmonary veins. Sustained atrial fibrillation is maintained by an atrial tissue substrate capable of accommodating many meandering wavelets. With continuing arrhythmia, the electrophysiological properties of the atria change and further facilitate continuing fibrillation. Treatment is aimed at prevention of thromboembolic complications, restoration and maintenance of sinus rhythm, and control of ventricular rate during atrial fibrillation. With greater understanding of the arrhythmia mechanisms, it is becoming possible to offer targeted curative treatments to more and more patients.

Atrial mechanical performance after internal and external cardioversion of atrial fibrillation: an echocardiographic study

OBJECTIVES

To compare the time course of resumption of mechanical performance of the left and right atrium after the novel method of internal low-energy cardioversion (CV) and conventional external CV of atrial fibrillation (AF).

BACKGROUND

Right atrial performance has been shown to normalize before the left atrium after external CV. However, no data on atrial function after internal CV are available.

PATIENTS AND INTERVENTIONS

Sixty-three patients with chronic AF were randomized to participate in either external or internal CV.

MEASUREMENTS

Echocardiographic examinations were carried out before as well as immediately after CV (day 0), and at days 1, 7, and 28 thereafter for the determination of cardiac dimensions, volumes, and transvalvular flow patterns.

RESULTS

After randomized internal CV or external CV, stable sinus rhythm was restored in 59 patients. Irrespective of the mode of CV, the right atrium resumed its mechanical function immediately after CV, whereas the left atrium was stunned beyond day 7. The mode of CV, internal or external, had no influence on the recovery of atrial mechanical function.

CONCLUSIONS

The right atrium resumes its normal function immediately after internal as well as external CV, whereas left atrium function is delayed. In contrast to the assumption that low-energy internal CV would impact less on atrial mechanical recovery, the type of method of CV used has no effect on such recovery.

Characteristics, outcome, and care of stroke associated with atrial fibrillation in Europe: data from a multicenter multinational hospital-based registry (The European Community Stroke Project)

BACKGROUND AND PURPOSE

The role of atrial fibrillation (AF) as a determinant of stroke outcome is not well established. Studies focusing on this topic relied on relatively small samples of patients, scarcely representative of the older age groups. We aimed at evaluating clinical characteristics, care, and outcome of stroke associated with AF in a large European sample.

METHODS

In a European Concerted Action involving 7 countries, 4462 patients hospitalized for first-in-a-lifetime stroke were evaluated for demographics, risk factors, clinical presentation, resource use, and 3-month survival, disability (Barthel Index), and handicap (Rankin scale).

RESULTS

AF was present in 803 patients (18.0%). AF patients, compared with those without AF, were older, were more frequently female, and more often had experienced a previous myocardial infarction; they were less often diabetics, alcohol consumers, and smokers (all P:<0.001). At 3 months, 32.8% of the AF patients were dead compared with 19.9% of the non-AF patients (P:<0.001). With control for baseline variables, AF increased by almost 50% the probability of remaining disabled (multivariate odds ratio 1.43, 95% CI 1.13 to 1.80) or handicapped (multivariate odds ratio 1.51, 95% CI 1.13 to 2.02). Before stroke, only 8.4% of AF patients were on anticoagulants. The chance of being anticoagulated was reduced by 4% per year of increasing age. AF patients underwent CT scan and other diagnostic procedures less frequently and received less physiotherapy or occupational therapy.

CONCLUSIONS

Stroke associated with AF has a poor prognosis in terms of death and function. Prevention and care of stroke with AF is a major challenge for European health systems.

Control of paroxysmal atrial fibrillation recurrence using combined administration of propafenone and quinidine

The frequent recurrence of paroxysmal atrial fibrillation (PAF) despite the use of standard antiarrhythmic agents prompted the use of new therapeutic approaches. There are few data on systematic assessment of PAF control with stepwise dose escalation and the use of a drug combination. Low-dose quinidine may promote the efficacy of propafenone by inhibiting its degradation through the cytochrome P450 pathway (CYP2D6). We prescribed propafenone 300 to 450 mg/day to 60 patients with PAF for 8 weeks, and 62% were symptomatically controlled. The 19 refractory patients were randomized in a double-blinded fashion to receive either a higher dose of propafenone (450 to 675 mg/day) or the standard dose of propafenone with low-dose quinidine 150 mg/day, each for an 8-week study period, and subsequently crossed over to the alternative treatment. The resulting serum propafenone concentrations were 259 +/- 208 and 336 +/- 237 mg/day (p >0.5), respectively. Both treatment arms prolonged the time to the first symptomatic atrial fibrillation (AF) recurrence and the interval between attacks, and AF was controlled in 37% of patients. However, the higher dose of propafenone was associated with gastrointestinal side effects not present with the low-dose quinidine combination. Of the 10 refractory patients, 7 were further controlled with a standard dose of propafenone plus quinidine (600 mg/day). Overall, control of PAF was achieved in 85% of patients at the end of 8 months; adverse effects necessitating withdrawal were observed in 6%, and uncontrolled AF in 5% of patients. There was no difference in the mean AF rate during recurrences in all phases, and ventricular proarrhythmia was not seen. This study documents the role of stepwise antiarrhythmic treatment of PAF. The use of a standard dose of propafenone, followed by low-dose quinidine combination to reduce propafenone degradation, and the combined standard dose of propafenone and quinidine may be used to maximize efficacy and tolerability.

Influence of left atrial enlargement and body weight on the development of atrial fibrillation: retrospective study on 205 dogs

We studied 205 dogs with cardiac diseases associated with left atrial enlargement (LAE). On the basis of electrocardiogram results, they were divided into: Group A, 50 dogs with atrial fibrillation (AF) and Group B, 155 dogs without AF. Group B was further subdivided in Group BI (123 dogs with sinus rhythm) and Group BII (32 dogs with cardiac arrhythmias other than AF). Bodyweight (BW) and left atrial diameter (LA) of Group A dogs were significantly greater (P< 0.05) than dogs in all other groups. The left atrium/aorta (LA/Ao) ratio of Group A dogs was significantly higher (P< 0.05) than that of dogs of Group B and BI. Using the couple of variables BW and LA, the logistic regression models were able to predict "non-development of AF" (with 92.3% probability) vs. "development of AF" (with 74% probability), and "maintaining sinus rhythm" (with 95.1% probability) vs."development of AF" (with 86% probability).

Reduced ventricular response irregularity is associated with increased mortality in patients with chronic atrial fibrillation

BACKGROUND-Variations in the ventricular response interval (VRI) during atrial fibrillation (AF) may be reduced in patients with adverse clinical outcomes. The properties of VRI dynamics associated with prognosis remain undetermined. METHODS AND RESULTS-In 107 patients with chronic AF (age, 64+/-9 years), we analyzed a 24-hour ambulatory ECG for VRI variability (SD, SD of successive differences, and SD of 5-minute averages) and VRI irregularity (Shannon entropy of histogram, symbolic dynamics, and approximate entropy of beat-to-beat and minute-to-minute fluctuations [ApEn(b-b) and ApEn(m-m)]). During a follow-up period of 33+/-16 months, 18 patients died (17%), 9 from cardiac causes, 7 from fatal strokes, and 2 from malignancies. Reductions in all VRI variability and irregularity measures were associated with an increased risk for cardiac death but not for fatal stroke. A significant association with cardiac death was also found for ejection fraction (relative risk, 1.10; 95% confidence interval [CI], 1.04 to 1.17, per 1% decrement) and ischemic AF (relative risk, 6.52; 95% CI, 1.62 to 26. 3). After adjustment for these clinical variables, all irregularity measures except symbolic dynamics had predictive value (relative risks [95% CIs] per 1SD decrement: Shannon entropy of histogram, 2. 03 [1.14 to 3.61]; ApEn(b-b), 1.72 [1.14 to 2.60]; and ApEn(m-m), 1. 90 [1.03 to 3.52]); however, the predictive power of variability measures was no longer significant. When the patients were stratified with the 33rd and 67th percentile values of ApEn(b-b) (1. 83 and 1.94, respectively), the 5-year cardiac mortality rates for the upper, middle, and lower tertiles were 0%, 13%, and 43%, respectively (log-rank test, P=0.04). CONCLUSIONS-Reduced VRI irregularity in a 24-hour ambulatory ECG has an independent prognostic value for cardiac mortality during long-term follow-up in patients with chronic AF.

The Management of Atrial Fibrillation in the ICU

Atrial tachyarrhythmias are the most frequent arrhythmias occurring in ICU patients, being particularly common in patients with cardiovascular and respiratory failure. Unlike ambulatory patients in whom atrial fibrillation/flutter (AF) is likely to be short lived, in the critically ill these arrhythmias are unlikely to resolve until the underlying disease process has improved. Urgent cardioversion is indicated for hemodynamic instability. Treatment in hemodynamically stable patients includes correction of treatable precipitating factors, control of the ventricular response rate, conversion to sinus rhythm, and prophylaxis against thromboembolic events in those patients who remain in AF. Diltiazem is the preferred agent for rate control, while procainamide and amiodarone are generally considered to be the antiarrhythmic agents of choice.

Natriuretic peptide levels in atrial fibrillation: a prospective hormonal and Doppler-echocardiographic study

OBJECTIVES

The objective was to determine the independent association between atrial fibrillation (A-Fib) and activation of natriuretic peptides.

BACKGROUND

The association of A-Fib with activation of N-terminal atrial and brain natriuretic peptides (N-ANPs and BNPs, respectively) is uncertain but of great importance for the diagnostic utilization of natriuretic peptides. This uncertainty is related to the lack of appropriate controls, with left ventricular (LV) and atrial overload similar to A-Fib.

METHODS

We prospectively measured N-terminal atrial and BNPs and endothelin-1 levels in 100 patients and 14 age- and gender-matched control subjects. The 32 patients with A-Fib were compared with 68 patients in sinus rhythm and similar LV and atrial overload (due to mitral regurgitation or LV dysfunction) measured simultaneously with hormonal levels with comprehensive Doppler echocardiography.

RESULTS

Patients with A-Fib compared with those in sinus rhythm had similar symptoms, comorbid conditions, cardioactive medications, pulmonary pressure, left atrial volume, and LV ejection fraction and filling characteristics but demonstrated higher N-ANP levels (2,613 +/- 1,681 vs. 1,654 +/- 1,323 pg/ml, p = 0.007) even after adjustment for the underlying cardiac disease (p < 0.0001). Conversely, BNP levels were similar in both groups (165 +/- 163 vs. 160 +/- 269 pg/ml, p = 0.9). In multivariate analysis, a higher N-ANP level was associated with A-Fib (p = 0.0003), symptom class (p < 0.0001) and endothelin-1 level (p = 0.032) independently of left atrial volume and LV ejection fraction. Conversely, BNP showed no independent association with and was most strongly associated with LV ejection fraction (p < 0.0001).

CONCLUSIONS

Atrial fibrillation is an independent determinant of higher N-ANP levels and blurs its association with LV dysfunction. Conversely, the BNP is not independently associated with A-Fib and is strongly determined by LV dysfunction, for which it is an independent marker.

Gemcitabine-induced atrial fibrillation: a hitherto unreported manifestation of drug toxicity

BACKGROUND

Gemcitabine is an antimetabolic drug for solid tumors. Although its pharmacokinetics as well as its side-effects are well known, paroxysmal atrial fibrillation associated to the administration of this drug has not yet been described.

PATIENTS AND METHODS

We describe the case of a 78-year-old man with pancreatic adenocarcinoma who presented repeated paroxysmal atrial fibrillation episodes 18-24 hours after every gemcitabine infusion which resolved with antiarrhythmic drugs. This clinical history was positive for a remote brief episode of atrial fibrillation, which resolved spontaneously, and the patient had no predisposing factors for supraventricular arrhythmias (systemic hypertension, diabetes or coronary artery disease).

RESULTS

Cardiac work-up revealed only a mild mitral-valve prolapse and complete right bundle branch block. During the arrhythmia episodes no other precipitating factors were reported. The close temporal relationship of the arrhythmia to drug administration and the recurrence of arrhythmia upon rechallenge allowed to hypothesize an intrinsic pro-arrhythmic effect of gemcitabine or its metabolite 2',2'-difluorodeoxyuridine.

CONCLUSIONS

The occurrence of atrial fibrillation during the administration of gemcitabine may be considered as a cardiac arrhythmia drug-related toxicity. This side-effect of gemcitabine infusion is a previously unreported sign of drug toxicity; therefore, a high level of awareness to this problem is warranted when this drug is administered.

Marked reduction in atrial defibrillation thresholds with repeated internal cardioversion

OBJECTIVES

This study was performed to assess the atrial defibrillation threshold in patients with recurrent atrial fibrillation (AF) using repeated internal cardioversion.

BACKGROUND

Previous studies in patients with chronic AF undergoing internal cardioversion have shown this method to be effective and safe. However, current energy requirements might preclude patients with longer-lasting AF from being eligible for an implantable atrial defibrillator.

METHODS

Internal shocks were delivered via defibrillation electrodes placed in the right atrium (cathode) and the coronary sinus (anode) or the right atrium (cathode) and the left pulmonary artery. After cardioversion, patients were orally treated with sotalol (mean 189 +/- 63 mg/day). Eighty consecutive patients with chronic AF (mean duration 291 +/- 237 days) underwent internal cardioversion, and sinus rhythm was restored in 74 patients. Eighteen patients underwent repeated internal cardioversion using the same electrode position and shock configuration after recurrence of AF (mean duration 34 +/- 25 days).

RESULTS

In these 18 patients, the overall mean defibrillation threshold was 6.67 +/- 3.09 J for the first cardioversion and 3.83 +/- 2.62 J for the second (p = 0.003). Mean lead impedance was 55.6 +/- 5.1 ohms and 57.1 +/- 3.7 ohms, respectively (not significant). For sedation, 6.7 +/- 2.9 mg and 3.9 +/- 2.2 mg midazolam were administered intravenously (p = 0.003), and the pain score (0 = not felt, 10 = intolerable) was 5.1 +/- 1.9 and 2.7 +/- 1.8 (p = 0.001). Uni- and multivariate analyses revealed only the duration of AF before cardioversion to be of relevance, lasting 175 +/- 113 days before the first and 34 +/- 25 days before the second cardioversion in these 18 patients (p = 0.002).

CONCLUSIONS

If the duration of AF is reduced, a significant reduction in defibrillation energy requirements for internal cardioversion ensues. This might extend the group of patients eligible for an implantable atrial defibrillator despite relatively high initial defibrillation thresholds.