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Background: Cardiac troponin T (cTnT) has been reported to be associated with cardiac mortality. In the present study, we evaluated the role of routine assessment of cTnT as a predictor of future cardiac death in patients with left ventricular (LV) dysfunction. Methods: Patients who were eligible for prophylactic implantable cardioverter defibrillator (ICD) were included from cardiac catheterization database. Inclusion criteria were patients with LV ejection fraction of ≤ 35% and with New York Heart Association (NYHA) ≥class II. Exclusion criteria were patients with acute coronary syndrome, ICD for secondary prevention, NYHA class IV, and lack of data. The final study patients were divided into the following three groups in accordance with two quartile points of serum cTnT levels: low cTnT, intermediate cTnT, and high cTnT groups. The primary endpoint of this study was cardiac death. Results: A total of 70 patients were included (mean age, 62±13 years; male individuals, 56; ischemic, 36; and non-ischemic, 34). During the observation period of 2.2 years, cardiac death was observed in 17 patients (fatal arrhythmic event, 9; heart failure, 7; myocardial infarction, 1). In the Kaplan–Meier analysis, the high cTnT group showed the highest risk among all the groups (p

A seventy year-old male was referred to our hospital to undergo radiofrequency catheter ablation (RFCA) for drug-refractory paroxysmal atrial fibrillation (AF). Pre-operative three-dimensional computed tomography revealed a unique left atrial (LA) roof vein. Electrophysiological findings showed expansion of the myocardial sleeve and local firing in the LA roof vein. We performed isolation of this arrhythmogenic abnormal vein concomitant with general pulmonary vein isolation in this case, and AF did not recur after the procedure.

Ventricular capture management is an automatic pacing threshold adjustment algorithm that automatically measures pacing threshold through detection of the evoked response after a pacing stimulus. Although it is principally designed to save device battery under the maintenance of the patient׳s safety, we experienced a rare case with serious pacing failure due to a weakness of this algorithm. This pacing failure might be explained by a large variation in the ventricular pacing threshold depending on the atrioventricular interval and daily variation of pacing threshold and concomitant steroid use in this patient. Keywords: Automatic pacing threshold adjustment algorithm, Pacing failure

Pneumothorax contralateral to the venous access site due to the right atrial lead is an uncommon complication. Concomitant steroid use is known as a risk factor of pacemaker lead perforation. We report a rare case of subacute contralateral pneumothorax due to a screw-in atrial lead perforation that occurred after dual-chamber pacemaker implantation in a patient who was receiving steroid therapy. The pneumothorax disappeared, and no recurrence was observed during follow-up with close observation alone.

The wearable cardioverter-defibrillator (WCD) represents an alternative clinical approach to prevent sudden cardiac death as a bridge to therapy when making a final decision regarding the need for an implantable cardioverter defibrillator (ICD), especially in patients who are in the so-called gray zone according to ICD guidelines. Although the WCD system was introduced in Japan in April 2014, data regarding its usage and experience are limited. We report the first case of appropriate shock therapy using the WCD in an outpatient setting in Japan. We describe the case of a 22-year-old-woman who received the first case of successful appropriate WCD shock therapy in an outpatient setting in Japan.

Background: Although amiodarone (AMD) is applied for implantable cardioverterdefibrillator (ICD) patients to reduce VT/VF events, its actual benefit and long-term efficacy are unclear. In the present study, we retrospectively evaluated the incidence of VT/VF events in ICD patients with and without AMD. Methods and results: The study population consisted of 77 consecutive patients with ICD therapy and structural heart diseases. They were followed up for 24 ± 3 months, and the incidences of VT/VF events or hospitalization were evaluated. When they were divided into two groups with and without VT/VF events (42:35), univariate analysis indicated a higher incidence of cardiomyopathy as the basic disease, VT as the initial arrhythmic diagnosis, higher levels of total bilirubin, and a lower incidence of AMD use in patients with VT/VF events. When they were divided by AMD use (24/53), VT/VF events were observed in 8/24 in patients with AMD (33.3%) and 34/53 without AMD (64.2%, p = 0:012). In sub-group analysis based on left ventricular ejection function (LVEF), the VT/VF event rate was lower in the AMD group in patients with LVEF < 40% (p = 0:007). Conclusions: AMD was considered to reduce VT/VF events in ICD patients, especially in the population with structural heart disease and lower LVEF.

Background: Antiarrhythmic agents may affect electrical remodeling but little is known regarding clinical cases. We evaluated fibrillation cycle length (FCL) of atrial fibrillation (AF) by spectral analysis of fibrillation waves (FW) in surface ECG for patients on antiarrhythmic agents. Methods and Results: 18 patients (14 males; 58 ± 2 year-old) with paroxysmal AF (pAF) lasting over 30 minutes recorded by Holter ECG were enrolled. FW was purified by subtraction of QRS-T, and calculated by fast Fourier transformation analysis. FCL was defined as reciprocal of mean peak frequency. Temporal variability was expressed as FCL coefficient of variation (FCL-CV). FCL and FCL-CV were calculated at 0, 1, 5, 10, and 30 minutes after the onset of AF. We evaluated three groups: control group (6 patients with no medication), class I group (6 patients with pilsicainide or flecainide), and bepridil group (6 patients with bepridil). FCL showed quick-shortening at first minute in control group (p < 0.001), and relatively slow-shortening in class I group. In bepridil group, FCL was not significantly shortened within 30 minutes. FCL-CV did not change, but was significantly larger in bepridil group. Conclusions: FCL of pAF showed significant shortening in control group, but FCL shortening was suppressed and FCL-CV was larger in bepridil group. This result may indicate the specific effect of bepridil for electrical changes in early phase of pAF.

Background: The current status of the efficacy of implantable cardioverter-defibrillator (ICD. and cardiac-resynchronization therapy with implantable defibrillator (CRT-D. in patients with left ventricular dysfunction needs to be clarified. Methods and Results: From the Japanese Cardiac Device Treatment Registry database, a total of 1,584 patients who had an LVEF ≦ 40% and had an ICD or CRT-D were selected as subjects in this study. The difference in the clinical characteristics between the primary and secondary prevention groups and the transition of the indications for device implantation over time were examined. Primary prevention gradually increased up to about 50% in all patients. The implantations of ICD/CRT-D for primary prevention in ischemic hear disease was significantly lower than that in dilated cardiomyopathy (33% vs 51%; p < 0.0001). The number of implantations for CRT-D for primary prevention increased dramatically over a one-year period. Conclusions: In Japan, the implantable defibrillator devices for primary prevention was significantly lower in ischemic heart disease compared with dilated cardiomyopathy. Further, an extension of the indications for ICD/CRT-D implantations has recently been occurring, especially with CRT-D devices for primary prevention.

Introduction: Although the atrial fibrillation cycle length (FCL) is considered to shorten in persistent atrial fibrillation (AF) as a result of electrical remodeling, whether a long-term change remains in FCL in patients with left ventricular (LV) dysfunction is uncertain. Morphological properties of AF waves were analyzed in patients with dilated cardiomyopathy (DCM). Methods and Results: The study population consisted of 43 patients with persistent AF, and they were divided into a DCM group (n = 14) and a control group (n = 29). Fibrillation waves from surface ECG lead V1 were purified by subtracting the QRS-T complex template. Power spectral analysis was performed by Fast Fourier Transformation, and the mean FCL was determined by the peak power frequency in 20 epochs at each recording. The LV ejection fraction was lower in the DCM group (50 ± 18%) than the control (63 ± 8%, p = 0.001). The mean FCL was shorter in the DCM group (132 ± 14 ms) than the control (151 ± 23 ms, p = 0.007) and there was a significant correlation between the FCL and LV dimensions (p = 0.03). Conclusion: In patients with persistent AF and LV dysfunction, FCL was shorter in comparison with the control, and seemed to be influenced by LV dimensions.