Impact of atrial fibrillation type (paroxysmal vs. non-paroxysmal) on long-term clinical outcomes: The RAFFINE registry subanalysis

BACKGROUND

The type of atrial fibrillation (AF) (paroxysmal or non-paroxysmal) is important in determining its therapeutic management. However, the prognostic impact of AF type on the incidence of cardiovascular events remains uncertain.

METHODS

We investigated patients with AF who were selected from an observational, multicenter, prospective registry (RAFFINE) comprising 4 university hospitals and 50 general hospitals/clinics in Japan between 2013 and 2015. In this subanalysis study, patients were divided into two groups according to their AF pattern at the time of enrollment. The primary outcome was the composite of death, ischemic stroke, and heart-failure-related hospitalization.

RESULTS

Among 3845 patients, 1472 (38.3 %) and 2373 (61.7 %) had paroxysmal and non-paroxysmal type AF, respectively. Patients with non-paroxysmal AF were older and had higher CHADS₂ score and prevalence of comorbidities. During median follow-up of 3.7 years, 681 (17.7 %) primary endpoints were identified. Cumulative incidences of the primary endpoint were significantly higher in the non-paroxysmal AF group; however, rates of bleeding events were not significantly different between the groups. Multivariate Cox hazard analysis showed that non-paroxysmal AF had significantly higher risk of cardiovascular events compared with paroxysmal AF (hazard ratio, 1.38; 95 % confidence interval, 1.17-1.64; p = 0.0002).

CONCLUSIONS

Non-paroxysmal AF was significantly associated with cardiovascular events. Long-term clinical outcomes might be improved if transition from paroxysmal to non-paroxysmal AF can be prevented.

Trend in Age at the Initial Pacemaker Implantation in Patients With Bradyarrhythmia - A 50-Year Analysis (1970-2019) in Japan

BACKGROUND

This study investigated whether the age of patients undergoing pacemaker implantation is increasing.Methods and Results: This study retrospectively reviewed the consecutive cases of 3,582 patients who underwent an initial pacemaker implantation at our hospitals because of symptomatic bradyarrhythmias between 1970 and 2019. The exclusion criteria were: patients with AV block due to cardiac surgery or AV junction ablation, and patients aged <20 years. The patients were divided into 5×10-year groups: those treated in the 1970s (1970-1979), 1980s (1980-1989), 1990s (1990-1999), 2000s (2000-2009), and 2010s (2010-2019). A total of 3,395 patients satisfied the study criteria. The average age at which the patients underwent a first pacemaker implantation increased across the 10-year periods: 63.7±13.2 years in the 1970s, 66.2±12.6 years (1980s), 69.1±12.4 years (1990s), 72.0±11.1 years (2000s), and 75.8±10.0 years (2010s) and advanced significantly in the 1990s, 2000s, and 2010s compared to the 1970s (all P<0.001). The ratio of patients aged ≥80 and ≥90 years increased from 10.6% and 0% in the 1970 s to 38.2% (P<0.001) and 5.2% (P= 0.017) in the 2010s, respectively.

CONCLUSIONS

The average age at initial pacemaker implantation increased by 12.1 years over the last 50 years in Japan. In particular, the ratios of ≥80 and ≥90 years as the patients age increased significantly.

Effects of Cardiac Massage and β-Blocker Pretreatment on the Success Rate of Cardiopulmonary Resuscitation Assessed by the Canine Ischemia/Reperfusion-Induced Ventricular Fibrillation Model

BACKGROUND

Effects of rapid electrical defibrillation and β-blockade on coronary ischemia/reperfusion-induced ventricular fibrillation (VF) during cardiopulmonary resuscitation (CPR) remain unknown.Methods and Results:After induction of VF by 30 min of ischemia followed by reperfusion, animals were treated with defibrillation alone (Group A, n=13), 2 min of open-chest cardiac massage followed by defibrillation (Group B, n=11), or the same therapy to Group B with propranolol (1 mg/kg, i.v.) treatment before ischemia/reperfusion (Group C, n=11). If return of spontaneous circulation (ROSC) was not attained, each therapy was repeated ≤3 times (Set-1). When ROSC was not obtained within Set-1, cardiac massage was applied to all animals followed by defibrillation, which was repeated ≤3 times (Set-2). ROSC after Set-1 was 8% in Group A, 82% in Group B and 82% in Group C, whereas that after Set-2 was 62% in Group A, 100% in Group B and 82% in Group C. Each animal with ROSC in Groups A (n=8) and B (n=11) showed sinus rhythm, whereas those in Group C (n=9) had sinus rhythm (n=5), atrial fibrillation (n=1), accelerated idioventricular rhythm (n=2) and atrioventricular block (n=1). Post ROSC heart rate and mean arterial pressure were significantly lower in Group C.

CONCLUSIONS

Cardiac massage increased the likelihood of ROSC vs. rapid defibrillation, but β-blocker pretreatment may worsen hemodynamics and electrical stability after ROSC.

The association between impairment of HDL cholesterol efflux capacity and atrial remodeling in atrial fibrillation

This cross-sectional study enrolled 202 patients with atrial fibrillation (AF) who had undergone catheter ablation and evaluated the association between high-density lipoprotein (HDL) functionality, cholesterol efflux capacity (CEC) of HDL, and the pathophysiology of left atrial structural remodeling. Participants were divided into two groups, based on their left atrial volume index (LAVI) (< 34 mL/m², n = 60 vs. LAVI ≥ 34 mL/m², n = 142). We quantified three types of HDL CECs by the presence or absence of cyclic-AMP, as entire, and CEC dependent or not dependent on ATP binding cassette transporter A1 (ABCA1) and termed them Global CEC, ABCA1 CEC, and Non-ABCA1 CEC, respectively. Consequently, Global and Non-ABCA1 CECs were significantly impaired in patients with an enlarged LA (Global CEC: p = 0.039, Non-ABCA1 CEC: p = 0.022). Logistic regression analyses demonstrated that Non-ABCA1 CEC was significantly associated with an enlarged LA after adjusting for the conventional risk factors of AF. Furthermore, the association of higher Non-ABCA1 CEC with an enlarged LA was independent of serum levels of HDL cholesterol and serum myeloperoxidase (Odds ratio of 1 standard deviation higher: 0.64, 95% confidence interval: 0.43–0.95, p = 0.027). The findings of this study indicate the potential contribution of reduced Non-ABCA1 CEC in HDL to the pathophysiology in left atrial structural remodeling of patients with AF.

Prognosis of Japanese Patients With Coronary Artery Disease Who Underwent Implantable Cardioverter Defibrillator Implantation - The JID-CAD Study

Background: There has been no large multicenter clinical trial on the prognosis of implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy with a defibrillator (CRT-D) in Japanese patients with coronary artery disease (CAD). The aim of the present study was to compare differences in the prognoses of Japanese patients with CAD between primary and secondary prevention, and to identify potential predictors of prognosis.

Methods and Results: We investigated 392 CAD patients (median age 69 years, 90% male) treated with ICD/CRT-D enrolled in the Japan Implantable Devices in CAD (JID-CAD) Registry. The primary endpoint was all-cause death, and the secondary endpoint was appropriate ICD therapies. Endpoints were assessed by dividing patients into primary prevention (n=165) and secondary prevention (n=227) groups. The mean (±SD) follow-up period was 2.1±0.9 years. The primary endpoint was similar in the 2 groups (P=0.350).

Conclusions: The mortality rate in Japanese patients with CAD who underwent ICD/CRT-D implantation as primary prevention was not lower than that of patients who underwent ICD/CRT-D implantation as secondary prevention, despite the lower cardiac function in the patients undergoing ICD/CRT-D implantation as primary prevention.

Levels of phospholipids and triacylglycerol-containing omega 3 fatty acids in myocardial tissue of patients with myocardial infarction: analyzed by a lipidomics profiling method

Objective

According to population-based studies, low omega 3 fatty acid (omega3FA) intake and high levels of serum triacylglycerol (TAG) are associated with cardiovascular diseases. Recent advances in mass spectrometry allow molecular lipid (lipidomics) profiling, which may enhance cardiovascular risk prediction. In this study, we assessed the levels of omega3FA-containing phospholipids (PL) and TAG in myocardial tissues of patients with and without myocardial infarction (MI) using a lipidomics profiling method.

Methods

We performed lipidomics profiling of human left atrial appendage (LAA) tissue of 29 consecutive patients receiving off-pump coronary bypass surgery with standard LAA resection. The patients were divided into the MI group (n=7) and an age- and gender-matched non-MI group (n=7).

Results

Lipidomics profiling revealed that the MI group tended to have low levels of phosphatidylcholines (PC), phosphatidylethanolamine (PE), lysophosphatidylethanolamine (LPE), and plasmalogen, and high levels of TAG species. Individual molecular species containing omega3FA, such as PC (18:0/20:5; 3,200±1,200 vs. 4,500±910 pmol/g tissue, p=0.04) and plasmalogen (18:1/20:5; 57,000±21,000 vs. 91,000±28,000 pmol/g tissue, p=0.02), were significantly lower in the MI group than in the non-MI group.

Conclusions

To our knowledge, this is the first study to determine the levels of omega3FA-containing PL and TAG in myocardial tissue using lipidomics profiling. We discovered that lower levels of omega3FA-containing PL and higher levels of TAG existed in myocardial tissues of patients with MI than in those of patients without MI. Accordingly, the lipidomics profiling method for human myocardial tissue may be useful for developing therapy targets for cardiovascular diseases.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): MEXT/JSPS KAKENHI Grant

Intratumoural immune cell landscape in germinoma reveals multipotent lineages and exhibits prognostic significance

AIMS

Alterations in microenvironments are a hallmark of cancer, and these alterations in germinomas are of particular significance. Germinoma, the most common subtype of central nervous system germ cell tumours, often exhibits massive immune cell infiltration intermingled with tumour cells. The role of these immune cells in germinoma, however, remains unknown.

METHODS

We investigated the cellular constituents of immune microenvironments and their clinical impacts on prognosis in 100 germinoma cases.

RESULTS

Patients with germinomas lower in tumour cell content (i.e. higher immune cell infiltration) had a significantly longer progression-free survival time than those with higher tumour cell contents (P = 0.03). Transcriptome analyses and RNA in-situ hybridization indicated that infiltrating immune cells comprised a wide variety of cell types, including lymphocytes and myelocyte-lineage cells. High expression of CD4 was significantly associated with good prognosis, whereas elevated nitric oxide synthase 2 was associated with poor prognosis. PD1 (PDCD1) was expressed by immune cells present in most germinomas (93.8%), and PD-L1 (CD274) expression was found in tumour cells in the majority of germinomas examined (73.5%).

CONCLUSIONS

The collective data strongly suggest that infiltrating immune cells play an important role in predicting treatment response. Further investigation should lead to additional categorization of germinoma to safely reduce treatment intensity depending on tumour/immune cell balance and to develop possible future immunotherapies.

Sex-Dependent Phenotypic Variability of an SCN5A Mutation: Brugada Syndrome and Sick Sinus Syndrome

Background Brugada syndrome ( BS ) is known to be 9 times more prevalent in males than females. However, little is known about the development of sick sinus syndrome in female members with familial BS . Methods and Results Familial BS patients and family members, both from our institutions and collaborating sites that specialize in clinical care of BS , participated in this study. We collected information on their clinical and genetic background, along with the inheritance patterns of BS . Detailed information on each case with familial BS is described. A total of 7 families, including 25 BS patients (12 females and 13 males), were included. Seven were probands and 18 were family members. Ten out of the 12 female patients and none of the 13 male patients developed sick sinus syndrome. Sudden death or spontaneous ventricular fibrillation occurred in 7 out of 13 male patients and 2 out of 12 female patients. Conclusions Familial BS existed in which female patients developed sick sinus syndrome but male patients did not. Some of those female patients with sick sinus syndrome had unrecognized BS . Information should be collected not only regarding a family history of sudden death or BS , but also whether a pacemaker was implanted in female members.

Stability of intrinsic rhythm in pacemaker-dependent patients during pacemaker replacement: Can we predict the need for temporary pacing?

BACKGROUND

In pacemaker-dependent patients, the risk of asystole must be managed during device replacement. This study aimed to examine whether we could predict the indication for temporary pacing (TP) during the generator replacement.

METHODS

We studied 105 consecutive patients who underwent pacemaker replacement due to battery depletion at Juntendo Nerima Hospital between September 2005 and December 2016. We examined the relationship between the stability of the intrinsic rhythm (IR) during pacemaker replacement and several clinical factors including age, gender, sick sinus syndrome or atrioventricular (AV) block, duration of pacing, structural heart disease, use of anti-arrhythmic drugs, and the presence/absence of a stable IR (>40 bpm) at the outpatient clinic (OPC) just before pacemaker replacement.

RESULTS

Of the 105 patients, we excluded 1 patient who required TP because of bradycardia-dependent torsades de points. Therefore, we evaluated 104 patients for the indication for TP. TP was underwent in 19 patients (18%) because of an absence or instability of the IR during pacemaker replacement. The indication for TP was significantly correlated with AV block (84% vs 48%, P = .0044) and the absence of a stable IR at the last OPC visit (89% vs 24%, P < .0001). For predicting the indication for TP, the following values of no stable IR at the last OPC visit were obtained: 89% sensitivity, 77% specificity, 46% positive predictive value, and 97% negative predictive value.

CONCLUSIONS

The presence of a stable IR at the last OPC visit was a good predictor (97%) of no indication for TP during pacemaker replacement.

Heart Failure with Hyperthyroidism Demonstrating Discrepancy between the Clinical Course and B-type Natriuretic Peptide Levels

A 35-year-old Japanese man was emergently admitted to our hospital with chief complaints of palpitation and dyspnea. He has been treated for Basedow's disease. He was diagnosed with acute decompensated heart failure, atrial fibrillation and thyrotoxicosis. We started anti-thyroid agents and a treatment for heart failure with beta blockers and diuretics under anti-coagulation therapy. His B-type natriuretic peptide levels remained high, although the heart failure had been compensated and the heart rate was well controlled while hyperthyroidism still existed. We should bear in mind that a discrepancy can exist between the clinical course and the B-type natriuretic peptide level in heart failure patients complicated with hyperthyroidism.

Brugada syndrome and sinus node dysfunction

Brugada syndrome (BrS) is a well-known catastrophic disease first reported in 1992 by the Brugada brothers. Ventricular fibrillation (VF) is an essential arrhythmia in BrS. An association between BrS and atrial tachyarrhythmias is not uncommon. However, sinus node dysfunction (SND) associated with BrS has not been well discussed. In this review, we focus on the association between BrS and SND. Based on previous reports describing clinical, epidemiological, and genetic evidence, SND is not a rare concomitant disorder in BrS. BrS may be a multiple conduction or arrhythmogenic disorder including not only the His-Purkinje system and right ventricle, but also the sinus node and atrium, derived from ion channel mutations.

Registry of Japanese patients with atrial fibrillation focused on anticoagulant therapy in the new era: The RAFFINE registry study design and baseline characteristics

BACKGROUND

The management of atrial fibrillation (AF) has evolved with the development of direct oral anticoagulants (DOACs), but data on their clinical effectiveness and safety outside clinical trial settings are limited.

METHOD

The RAFFINE registry is an observational, multicenter, prospective registry of Japanese patients with AF, designed to follow clinical events over 3 years. Patient enrollment was conducted from 2013 to 2015 at university hospitals, general hospitals, and private clinics to ensure inclusion of a broad spectrum of representative AF patients. The primary outcome events in this study will be ischemic stroke, systemic embolism, and major bleeding.

RESULT

We enrolled 3901 ambulatory patients with AF from 4 university hospitals and 50 general hospitals/clinics in Japan. The mean patient age was 72.6 years and 68.5% were male. The type of AF was paroxysmal in 37.8%, persistent in 9.3%, and permanent in 51.7%. Major coexisting diseases were hypertension (72.7%), diabetes mellitus (30.3%), congestive heart failure (23.8%), history of ischemic stroke or transient ischemic attack (15.1%), and coronary artery disease (13.7%). Of the entire cohort, 44.6% were treated with warfarin and 43.0% were treated with DOACs. The prescription of DOACs exceeded that of warfarin in the general hospitals and clinics. Risk scores such as CHADS₂ score, CHA₂DS₂-VASc score, and HAS-BLED score were higher in patients at university hospitals than in patients at general hospitals or clinics.

CONCLUSION

The RAFFINE registry at baseline described the current status of anticoagulation therapy in Japan and long-term follow-up data will identify how outcomes vary between stratified groups in patients with AF in the DOAC era (UMIN Clinical Trials Registry UMIN000009617).

High extracellular Ca2+ enhances the adipocyte accumulation of bone marrow stromal cells through a decrease in cAMP

Bone marrow stromal cells (BMSCs) are common progenitors of both adipocytes and osteoblasts. We recently suggested that increased [Ca²⁺]_o caused by bone resorption might accelerate adipocyte accumulation in response to treatment with both insulin and dexamethasone. In this study, we investigated the mechanism by which high [Ca²⁺]_o enhances adipocyte accumulation. We used primary mouse BMSCs and evaluated the levels of adipocyte accumulation by measuring Oil Red O staining. CaSR agonists (both Ca²⁺ and Sr²⁺) enhanced the accumulation of adipocytes among BMSCs in response to treatment with both insulin and dexamethasone. We showed that high [Ca²⁺]_o decreases the concentration of cAMP using ELISA. Real-time RT-PCR revealed that increasing the intracellular concentration of cAMP (both chemical inducer (1μM forskolin and 200nM IBMX) and a cAMP analog (10μM pCPT-cAMP)) suppressed the expression of PPARγ and C/EBPα. In addition, forskolin, IBMX, and pCPT-cAMP inhibited the enhancement in adipocyte accumulation under high [Ca²⁺]_o in BMSCs. However, this inhibited effect was not observed in BMSCs that were cultured in a basal concentration of [Ca²⁺]_o. We next observed that the accumulation of adipocytes in the of bone marrow of middle-aged mice (25-40 weeks old) is higher than that of young mice (6 weeks old) based on micro CT. ELISA results revealed that the concentration of cAMP in the bone marrow mononuclear cells of middle-aged mice is lower than that of young mice. These data suggest that increased [Ca²⁺]_o caused by bone resorption might accelerate adipocyte accumulation through CaSR following a decrease in cAMP.

Left Atrial Appendage Volume and Plasma Docosahexaenoic Acid Levels Are Associated With Atrial Fibrillation Recurrence After Catheter Ablation

BACKGROUND

Risk factors for atrial fibrillation (AF) recurrence in patients who have undergone AF catheter ablation have not been fully clarified. The objective of this study was to assess whether the left atrium (LA) and LA appendage (LAA) volumes, and cardio-metabolic markers such as polyunsaturated fatty acids (PUFAs) levels were associated with AF recurrence.

METHODS

Seventy-seven consecutive patients with AF (mean age, 59 ± 8 years; male, 81%; paroxysmal AF, 64%) undergoing catheter ablation were enrolled. Using contrast-enhanced cardiac multi-detector computed tomography (MDCT) scan, the LA and LAA volume and orifice area were assessed. Radiofrequency ablation was performed by an irrigation catheter, initially targeting the pulmonary veins with a wide area circumferential ablation.

RESULTS

Patients with AF recurrence (36%) exhibited both larger LAA volumes and an LAA orifice area than those without AF recurrence, whereas the LA diameter and LA volumes were not significantly different. Notably, AF recurrence occurred in all patients with a large LAA (≥ 25 mL), and the LAA volume was significantly and negatively associated with docosahexaenoic acid (DHA) levels (β = -0.33, P = 0.003). A multiple regression analysis revealed that the log N-terminal proB-type natriuretic peptide and plasma DHA levels were independent factors for the LAA volume when adjusted for age, AF detected age, left ventricular (LV) ejection fraction, end-systolic LV diameter.

CONCLUSIONS

These results suggest that the association between LAA volume and low plasma DHA levels may be an important factor for post-ablation AF recurrence.

Unusual Pharyngeal Pain Caused by Acute Coronary Syndrome: A Report of Three Cases

Most patients complaining of pharyngeal pain have an upper respiratory tract infection or other local explanation for their pain. Here we show 3 rare cases of patients visiting our Otorhinolaryngology Department who had an initial symptom of pharyngeal pain caused by acute coronary syndrome (ACS). An electrocardiogram and a cardiac biomarker test are recommended to exclude ACS with atypical presentation in cases without pharyngolaryngeal findings comparable to pharyngeal pain.

A proposal of clinical ECG index "vagal score" for determining the mechanism of paroxysmal atrioventricular block

Background

Paroxysmal atrioventricular block (P-AVB) is a well-known cause of syncope; however, its underlying mechanism is difficult to determine. This study aimed to evaluate a new ECG index, the “vagal score (VS),” to determine the mechanism of P-AVB.

Methods

We evaluated the VS in 20 patients with P-AVB (13 men, 7 women; aged 25–78 years [mean, 59.3 years]). The VS was developed by assigning 1 point each for the following: (1) no AVB or intraventricular conduction disturbance on the baseline ECG, (2) PR prolongation immediately before P-AVB, (3) sinus slowing immediately before P-AVB, (4) initiation of P-AVB by PP prolongation, (5) sinus slowing during ventricular asystole, and (6) resumption of AV conduction with PP shortening, and by assigning –1 point each for (7) the initiation of P-AVB by a premature beat, and (8) resumption of AV conduction by an escape beat. Based on the clinical situations and electrophysiologic findings, we considered the mechanism of P-AVB as vagally mediated or intrinsic conduction disease (ICD).

Results

The VS ranged from 5 to –2 points for each patient. Five patients with a definite vagally mediated P-AVB had high VSs (3–5 points). We observed characteristic ECG findings of ICD consisting of changes in AV conduction by an extrasystole and/or escape beat in only 5 of the 6 patients (83%) with a low VS (1 to –2).

Conclusions

The VS is simple and potentially useful for determining the mechanism of P-AVB. P-AVB with a VS ≥3 strongly suggested a vagally mediated mechanism.

Impacts of Surgically Performed Renal Denervation on the Cardiovascular and Electrophysiological Variables in the Chronic Atrioventricular Block Dogs - Comparison With Those of Amiodarone Treatment

BACKGROUND

In order to begin to precisely clarify the impact of renal denervation on the blood pressure, atrial fibrillation and ventricular tachyarrhythmias, in addition to proarrhythmic potential, its cardiovascular effects were assessed by using the chronic complete atrioventricular block dogs.

METHODS AND RESULTS

Cardiohemodynamic and electrophysiological effects, together with neurohumoral factors and/or electrolytes, were assessed before and 4 weeks after either renal denervation (n=5) or amiodarone treatment (n=6). Amiodarone hydrochloride was given orally to the animals every day in a dose of 200 mg/day for the first 7 days followed by 100 mg/day for the following 21 days. The renal denervation decreased the systolic pressure, idioventricular rate, prolonged ventricular effective refractory period, and slightly suppressed the adrenergic tone and the renin-angiotensin-aldosterone system, but hardly affected the atrial effective refractory period and terminal repolarization period. Amiodarone prolonged the atrial effective refractory period, whereas no significant change was detected in the other variables.

CONCLUSIONS

Surgically performed renal denervation may possess the anti-ventricular tachyarrhythmic rather than anti-atrial fibrillatory potentials, and it also modestly decreased the blood pressure. Thus, currently obtained information may be used as guidance for better understanding the utility and limitation of renal denervation against various types of cardiovascular diseases. (Circ J 2016; 80: 1556-1563).

Long-term reliability of sweet-tip type screw-in leads

Background

Active fixation leads have provided stable atrial and ventricular pacing; however, long-term follow-up data have not been satisfactory. The purpose of this study was to investigate the long-term reliability of active fixation leads and their electrical characteristic stability.

Methods

A total of 1196 pacing leads were implanted in 830 patients consecutively between 2002 and 2013. In this retrospective study, we were able to trace 1092 leads in 750 patients to investigate the prognosis of implanted leads. The measurement values (including pacing thresholds, sensing amplitudes, and lead impedances of both the atrial and ventricular leads) were obtained from medical records at the time of implantation and during follow up at the outpatient device clinic. All pacing leads were FINELINE II Sterox EZ Leads (Boston Scientific, MN, USA), which are sweet-tip type screw-in active fixation leads, except for the shock leads in patients with implantable cardioverter defibrillator.

Results

The mean follow-up period was 51.3±29.2 months (median, 48 months). A total of 1092 leads were implanted in either the atrium (682 leads) or the ventricle (410 leads). Venous access was achieved through cephalic vein cut down (CVC) method (914 leads) or the subclavian vein puncture (SVP) method (178 leads). The overall lead survival rate was 99.6% at both 5 and 10 years. Lead fracture was observed in 4 of 1092 leads (0.37%), all of which were implanted by the SVP method. No lead fracture occurred among patients wherein CVC method was applied (p<0.01). Device-related infection was observed in four patients (0.53%).

Conclusions

The overall reliability and stability of sweet-tip type screw-in leads were satisfactory throughout the long-term follow-up period (median, 4 years). Because it was associated with less lead fractures, cut-down access from the cephalic vein may be recommended as the first-line approach when considering the importance of long-term durability of pacing leads.

Effects of endothelin on cultured human and rat glomerular mesangial cells

Figure 5 summarizes our results and the data in the literature with regard to both short-term signalling and long-term signalling induced by endothelin. Short-term signalling, which induces vasoconstriction, is undoubtedly mediated by multiple signals including increments of cytosolic calcium, stimulation of protein kinase C and alkalinization of the cytosol. Endothelin also activates negative feedback pathways including arachidonate release with the synthesis of vasorelaxant prostaglandins and potentiation, in a prostaglandin-dependent manner, of beta-adrenergic-stimulated adenylate cyclase. Long-term signalling is less well understood and may depend not only on phospholipase activation with subsequent changes of calcium and protein kinase C but also stimulation of other protein kinases which phosphorylate key intermediates. Endothelin stimulates the transient appearance of protooncogenes that might play a role in the induction of cellular proliferation.

Japan Implantable Devices in Coronary Artery Disease (JID-CAD) study design

BACKGROUND

There is little information regarding appropriate therapies for coronary artery disease (CAD) patients with implantable devices - such as implantable cardioverter-defibrillators (ICDs), cardiac resynchronization therapy devices (CRT-Ds) and cardiac resynchronization therapy pacemaker (CRT-P) devices - in Japan. To address this lack of information, we have launched the Japan Implantable Devices in Coronary Artery Disease (JID-CAD) study.

METHODS

This study has been designed as a prospective, multicenter, non-randomized and observational investigation. All patients will be followed up every six months over a two-year period. The primary endpoint will be the administration of appropriate device therapy. Secondary endpoints include administration of inappropriate therapy, death, hospitalization, or cardiovascular events.

CONCLUSION

In this report, we discuss the current clinical situation of appropriate therapy, and how it is influenced by catheter ablation and revascularization therapy in patients with CAD.

Increased extracellular and intracellular Ca²⁺ lead to adipocyte accumulation in bone marrow stromal cells by different mechanisms

Mesenchymal stem cells found in bone marrow stromal cells (BMSCs) are the common progenitors for both adipocyte and osteoblast. An increase in marrow adipogenesis is associated with age-related osteopenia and anemia. Both extracellular and intracellular Ca(2+) ([Ca(2+)]o and [Ca(2+)]i) are versatile signaling molecules that are involved in the regulation of cell functions, including proliferation and differentiation. We have recently reported that upon treatment of BMSCs with insulin and dexamethasone, both high [Ca(2+)]o and high [Ca(2+)]i enhanced adipocyte accumulation, which suggested that increases in [Ca(2+)]o caused by bone resorption may accelerate adipocyte accumulation in aging and diabetic patients. In this study, we used primary mouse BMSCs to investigate the mechanisms by which high [Ca(2+)]o and high [Ca(2+)]i may enhance adipocyte accumulation. In the process of adipocyte accumulation, two important keys are adipocyte differentiation and the proliferation of BMSCs, which have the potential to differentiate into adipocytes. Use of MTT assay and real-time RT-PCR revealed that high [Ca(2+)]i (ionomycin)-dependent adipocyte accumulation is caused by enhanced proliferation of BMSCs but not enhanced differentiation into adipocytes. Using fura-2 fluorescence-based approaches, we showed that high [Ca(2+)]o (addition of CaCl2) leads to increases in [Ca(2+)]i. Flow cytometric methods revealed that high [Ca(2+)]o suppressed the phosphorylation of ERK independently of intracellular Ca(2+). The inhibition of ERK by U0126 and PD0325901 enhanced the differentiation of BMSCs into adipocytes. These data suggest that increased extracellular Ca(2+) provides the differentiation of BMSCs into adipocytes by the suppression of ERK activity independently of increased intracellular Ca(2+), which results in BMSC proliferation.

Abstract 294: Decreased Plasma Omega-3 to Omega-6 Polyunsaturated Fatty Acid Ratio Associated with Apical Ballooning Syndrome (Tako-Tsubo cardiomyopathy -TTC)

Background: Eicosapentaenoic acid (EPA) of the omega-3 polyunsaturated fatty acids (ω-3 PUFA) family plays important roles in the prevention of cardiovascular disease, while, arachidonic acid (AA) of the ω-6 PUFA family promotes inflammatory and prothrombotic influences. Tako-Tsubo cardiomyopathy (TTC) is a heart syndrome associated with transient myocardial contractile dysfunction. Decreased endothelial function in response to acute mental stress has been reported in patients with a prior episode of TTC. However, the pathogenesis of TTC remains unclear and the relationship between TTC and EPA/AA ratio has not been elucidated.

Methods and Results: This study consisted of 10 consecutive patients with clinically diagnosed TTC. The aim of this study was to investigate the association between the plasma EPA/AA ratio and the early stage of clinically diagnosed TTC. To examine the plasma fatty acid level, blood samples were obtained from control, old myocardial infarction, and clinically diagnosed TTC patients. A clinically diagnosed TTC patients revealed a lower plasma EPA/AA ratio [Control patients, 0.58 (n=18) vs OMI patients, 0.38 (n=22) vs TTC patients, 0.12 (n=10), p=0.011]. High-sensitivity CRP levels and a low plasma EPA/AA ratio could independently predict the prevalence of TTC on multivariate logistic regression analysis [odds ratio 1.83 (95%CI 1.03-3.25), p=0.036 and odds ratio 2.05 (95%CI 1.12-3.92), p=0.02)].

Conclusion: In patients with TTC, a low plasma EPA/AA ratio was significantly associated with the early stage of clinically diagnosed TTC. The findings implicate lower EPA/AA ratio and the following endothelial dysfunction as a potential mechanism involved in the pathogenesis of this unique cardiomyopathy.

Effects of candesartan on electrical remodeling in the hearts of inherited dilated cardiomyopathy model mice

Inherited dilated cardiomyopathy (DCM) is characterized by dilatation and dysfunction of the ventricles, and often results in sudden death or heart failure (HF). Although angiotensin receptor blockers (ARBs) have been used for the treatment of HF, little is known about the effects on postulated electrical remodeling that occurs in inherited DCM. The aim of this study was to examine the effects of candesartan, one of the ARBs, on cardiac function and electrical remodeling in the hearts of inherited DCM model mice (TNNT2 ΔK210). DCM mice were treated with candesartan in drinking water for 2 months from 1 month of age. Control, non-treated DCM mice showed an enlargement of the heart with prolongation of QRS and QT intervals, and died at t_1/2 of 70 days. Candesartan dramatically extended the lifespan of DCM mice, suppressed cardiac dilatation, and improved the functional parameters of the myocardium. It also greatly suppressed prolongation of QRS and QT intervals and action potential duration (APD) in the left ventricular myocardium and occurrence of ventricular arrhythmia. Expression analysis revealed that down-regulation of Kv4.2 (I_to channel protein), KChIP2 (auxiliary subunit of Kv4.2), and Kv1.5 (I_Kur channel protein) in DCM was partially reversed by candesartan administration. Interestingly, non-treated DCM heart had both normal-sized myocytes with moderately decreased I_to and I_Kur and enlarged cells with greatly reduced K⁺ currents (I_to, I_Kur I_K1 and I_ss). Treatment with candesartan completely abrogated the emergence of the enlarged cells but did not reverse the I_to, and I_Kur in normal-sized cells in DCM hearts. Our results indicate that candesartan treatment suppresses structural remodeling to prevent severe electrical remodeling in inherited DCM.

Recurrent ventricular fibrillation under sufficient medical treatment in patient with coronary artery spasm

In cases of coronary artery spasm, life-threatening ventricular arrhythmias are possible and can lead to sudden cardiac death. Treatment for this condition includes implantable cardioverter defibrillators, but their effectiveness in patients who present with ventricular fibrillation is debated. Our patient presented with intractable ventricular fibrillation episodes that triggered shocks from her implanted defibrillator. At 2 years of follow-up, we placed her on 200 mg/day of oral amiodarone, after identifying short-coupled premature contractions as the trigger for the ventricular fibrillation. In the 2 years following initiation of this drug therapy, the patient had no further fibrillation episodes.

Usefulness of running wheel for detection of congestive heart failure in dilated cardiomyopathy mouse model

Background

Inherited dilated cardiomyopathy (DCM) is a progressive disease that often results in death from congestive heart failure (CHF) or sudden cardiac death (SCD). Mouse models with human DCM mutation are useful to investigate the developmental mechanisms of CHF and SCD, but knowledge of the severity of CHF in live mice is necessary. We aimed to diagnose CHF in live DCM model mice by measuring voluntary exercise using a running wheel and to determine causes of death in these mice.

Methodology/Principal Findings

A knock-in mouse with a mutation in cardiac troponin T (ΔK210) (DCM mouse), which results in frequent death with a t_1/2 of 70 to 90 days, was used as a DCM model. Until 2 months of age, average wheel-running activity was similar between wild-type and DCM mice (approximately 7 km/day). At approximately 3 months, some DCM mice demonstrated low running activity (LO: <1 km/day) while others maintained high running activity (HI: >5 km/day). In the LO group, the lung weight/body weight ratio was much higher than that in the other groups, and the lungs were infiltrated with hemosiderin-loaded alveolar macrophages. Furthermore, echocardiography showed more severe ventricular dilation and a lower ejection fraction, whereas Electrocardiography (ECG) revealed QRS widening. There were two patterns in the time courses of running activity before death in DCM mice: deaths with maintained activity and deaths with decreased activity.

Conclusions/Significance

Our results indicate that DCM mice with low running activity developed severe CHF and that running wheels are useful for detection of CHF in mouse models. We found that approximately half of ΔK210 DCM mice die suddenly before onset of CHF, whereas others develop CHF, deteriorate within 10 to 20 days, and die.