Tadateru Iwayama

The role of epicardial adipose tissue in coronary artery disease in non-obese patients

BACKGROUND Epicardial adipose tissue (EAT) surrounding the heart may contribute to the development of coronary artery disease (CAD) through its local secretion of adipocytokines. Although the quantity of EAT is associated with obesity and metabolic syndrome, the role of EAT in the development of CAD in non-obese patients remains to be determined. METHODS This study included 41 patients with CAD who underwent coronary artery bypass graft surgery and 28 patients without CAD who underwent other cardiac surgery. EAT volume was measured by 64-slice multi-detector computed tomography before the surgery. We obtained pericardial fluid and epicardial and subcutaneous adipose tissue samples at the surgery. We investigated the relationship between EAT volume and adiponectin levels in pericardial fluid and incident CAD in patients with and without obesity (body mass index>25 kg/m(2)). RESULTS There was no significant difference in EAT volume between obese patients with and without CAD (55.5 ± 40.2 mL vs. 40.1 ± 19.7 mL, p=0.323). However, EAT volume was significantly greater in non-obese patients with CAD compared to those without CAD (35.0 ± 18.8 mL vs. 15.7 ± 11.0 mL, p<0.001). Adiponectin concentrations in pericardial fluid were significantly lower in non-obese patients with CAD compared to those without CAD (2.7 ± 2.0 μg/mL vs. 4.3 ± 3.7 μg/mL, p=0.049), whereas the adiponectin levels were decreased in obese patients regardless of the presence of CAD. Non-obese patients with CAD had significantly larger size adipocytes in EAT but not subcutaneous adipose tissue compared to those without CAD. Multiple logistic regression analysis showed that increased EAT volume was independently associated with incident CAD in non-obese patients. CONCLUSION Increased EAT may play a crucial role in development of CAD through impairment of adiponectin secretion in non-obese patients.

Predictors of Left Atrial Coagulation Activity Among Paroxysmal Atrial Fibrillation Patients

BACKGROUND The difference between left atrial (LA) and systemic coagulation activity in paroxysmal atrial fibrillation (PAF) is unclear. METHODS AND RESULTS We enrolled 100 patients with PAF who underwent AF ablation. Warfarin was stopped 1 day before the procedure. LA volume index and LA emptying fraction were measured by 64-slice multidetector computed tomography. Immediately after transseptal puncture, blood samples were simultaneously collected from the LA and systemic circulation (SC). In addition, to evaluate the effect of warfarin on D-dimer levels we recruited an additional 27 PAF patients on continuous warfarin. Even in patients with low CHADS2 scores (mean 0.59 ± 0.68) and during sinus rhythm, the prevalence of positive LA-D-dimer (≥ 0.5 µg/ml) was greater than that of SC-D-dimer (23% vs. 10%, P<0.01). The LA-D-dimer-positive patients had a larger mean LA volume index and reduced LA emptying fraction than the LA-D-dimer-negative patients. Multiple logistic regression analysis revealed that LA volume index was independently correlated with positive LA-D-dimer (odds ratio 2.245, 95% confidence interval 1.194-4.626, P=0.0112). The prevalence of positive LA-D-dimer was significantly lower in patients taking continuous warfarin, than in those on discontinuous warfarin (3.7% vs. 23%, P=0.025). CONCLUSIONS An enlarged LA volume index was associated with high LA coagulation status in patients with paroxysmal AF. Adequate warfarin control during AF catheter ablation may reduce the prevalence of positive LA-D-dimer.

Prevention of immediate recurrence of atrial fibrillation with low-dose landiolol after radiofrequency catheter ablation

Immediate recurrence of atrial fibrillation (AF) after radiofrequency (RF) catheter ablation is commonly observed within 3 d after the procedure. The mechanism and pharmacological management of immediate AF recurrence remain unclear.

ST-segment elevation and ventricular fibrillation shortly after transseptal puncture for left atrial catheter ablation

A 47‐year‐old man with drug‐resistant paroxysmal atrial fibrillation underwent left atrial (LA) catheter ablation. After sheaths were inserted into the LA using the Brockenbrough method, he complained of angina and developed ST‐segment elevation in the II, III, aVF, V5, and V6 leads. Ventricular fibrillation (VF) occurred followed by ventricular tachycardia. The VF was successfully treated with direct current shock. Coronary angiography with isosorbide dinitrate showed neither spasm nor embolism in the coronary artery. The chest pain disappeared after 6 min with resolution of the ST‐segment elevation. A summarized review of ST‐segment elevation associated with transseptal puncture disclosed that ST‐segment elevation is often found in inferior leads (87.5%), while concomitant bradyarrhythmia has been reported in 43.8% of patients. Our patient is the first recorded case with potentially lethal tachyarrhythmia. Although ST‐segment elevation and VF is a rare complication associated with transseptal puncture, awareness of this complication is important.

Decreased left ventricular stroke volume is associated with low-grade exercise tolerance in patients with chronic obstructive pulmonary disease

Background Low-grade exercise tolerance is associated with a poor prognosis in patients with chronic obstructive pulmonary disease (COPD). The 6 min walk test (6MWT) is commonly used to evaluate exercise tolerance in patients with COPD. However, little is known regarding the relationship between cardiac function and exercise tolerance in patients with COPD. The aim of this study was to identify predictive factors in cardiac function for low-grade exercise tolerance in patients with stable COPD. Methods We recruited 57 patients with stable COPD (men 54, women 3) to perform the 6MWT. Patients with underlying orthopaedic disease or heart failure were excluded. Cardiac function was evaluated by echocardiography and contrast-enhanced cardiac CT. We also measured pulmonary function and the 6MWT distance. Results Forced expiratory volume in 1 s (FEV1) and per cent predicted FEV, along with left ventricular end diastolic volume and left ventricular cardiac output as measured by cardiac CT, were significantly related to the 6MWT distance. On multivariate analysis, left ventricular stroke volume was the factor most closely associated with a decreased walked distance in the 6MWT. Conclusions Decreased left ventricular stroke volume was associated with low-grade exercise tolerance in patients with stable COPD without heart failure.

Circulating heart-type fatty acid-binding protein levels predict ventricular fibrillation in Brugada syndrome

BACKGROUND The association between ongoing myocardial damage and outcomes in patients with Brugada syndrome who had received an implantable cardioverter-defibrillator (ICD) is unclear. METHODS Consecutive patients with Brugada syndrome (n=31, 50±13 years) who had received an ICD were prospectively enrolled. Minor myocardial membrane injury [heart-type fatty acid-binding protein (H-FABP) >2.4ng/mL] and myofibrillar injury (troponin T >0.005ng/mL) were defined using receiver operating characteristic curves. Patients were followed for a median period of 5 years to an endpoint of appropriate ICD shock. RESULTS Myocardial membrane injury (29%) and myofibrillar injury (26%) were similarly prevalent among patients with Brugada syndrome who had received ICDs. Appropriate ICD shocks occurred in 19% of patients during the follow-up period. Multivariate Cox regression analysis showed that serum H-FABP level >2.4ng/mL, but not troponin T level, was an independent prognostic factor for appropriate ICD shock due to ventricular fibrillation [hazard ratio (HR) 25.2, 95% confidence interval (CI) 1.33-1686, p=0.03]. CONCLUSIONS Evaluating myocardial damage using H-FABP may be a promising tool for predicting ventricular arrhythmia in patients with Brugada syndrome who have received ICDs.

The association between defibrillation shock energy and acute cardiac damage in patients with implantable cardioverter defibrillators.

The aim of this study was to establish a minimally invasive defibrillation testing (DT) protocol for patients with implantable cardioverter defibrillators (ICDs).

The Neutrophil-to-Lymphocyte Ratio Predicts All-Cause Mortality in Patients with Implantable Cardioverter Defibrillators: NEUTROPHIL-TO-LYMPHOCYTE RATIO IN ICD RECIPIENTS

The relationship between the neutrophil‐to‐lymphocyte ratio (NLR) and outcome in patients with implantable cardioverter‐defibrillators (ICDs) is unclear.

Low arterial blood oxygenation is associated with calcification of the coronary arteries in patients with chronic obstructive pulmonary disease.

BACKGROUND Cigarette smoking is a well-known major cause of both chronic obstructive pulmonary disease (COPD) and atherosclerosis. However, few studies have investigated the correlation between COPD and coronary atherosclerosis. METHODS We recruited 54 patients with stable COPD (51 men, 3 women) but without angina symptoms. Arterial blood gas analyses were performed, pulmonary function was assessed, and calcification of the coronary arteries was evaluated by computed tomography (CT). RESULTS Calcification of the coronary arteries was noted in 25 patients. There were no significant differences in age, body mass index, respiratory function, and levels of low-density lipoprotein cholesterol, hemoglobin A1c, glucose, or C-reactive protein between patients with or without calcification of the coronary arteries. Arterial blood oxygenation was significantly lower in patients with calcification of the coronary arteries. On both univariate and multivariate analyses, low arterial blood oxygenation was an independent risk factor for calcification of the coronary arteries. CONCLUSIONS In patients with COPD, low arterial blood oxygenation was strongly associated with calcification of the coronary arteries and may be a significant predictor of cardiovascular disease.

Electroanatomical mapping of the atrialized right ventricle: Placement of a transvenous implantable cardioverter-defibrillator in a patient with Ebstein’s anomaly

A 47‐year‐old woman with Ebsteins anomaly suffered from an out‐of‐hospital cardiac arrest caused by ventricular fibrillation. Electroanatomical activation mapping showed an atrialized right ventricle. Atrial electrocardiogram, normal atrioventricular node conduction delay, and ventricular electrocardiogram were confirmed in the right atrium. Relatively preserved ventricular amplitude was found in the septal wall. Based on these findings, a transvenous dual‐chamber implantable cardioverter‐defibrillator was implanted for the prevention of sudden cardiac death. The patient has fared well, without any lead malfunctions, lead dislodgement, or inappropriate shocks. Sufficiently high atrial and ventricular amplitudes were confirmed during 18 months of follow‐up.