Heart failure（HF）is a major cause of death in arrhythmogenic right ventricular cardiomyopathy（ARVC）. The purpose of this study was to elucidate the clinical impact and risk factors of HF in patients with ARVC. We evaluated cardiac adverse outcomes including HF in 113 consecutive patients with ARVC（85 men, mean age : 44±15 years）. During a median follow-up of 10.0 years（interquartile range : 5.2 to 15.7 years）, 29 patients（26％）were hospitalized for progressive HF. Patients with one or more episodes of HF hospitalization had about a 10-fold increased incidence of cardiac death（48％ vs. 4.7％, p＜0.0001）. Left ventricular ejection fraction（LVEF）and right ventricular ejection fraction（RVEF）were significantly lower in patients with HF hospitalization than in patients without HF hospitalization（LVEF, 45±15 vs. 54±13％, p=0.001 ; RVEF, 26±10 vs. 33±11％, p=0.003, respectively）. Regarding the ECG findings, the prevalence of first-degree atrioventricular block（AVB）and epsilon waves were significantly higher in patients with HF hospitalization than in those without HF hospitalization（first-degree AVB, 48％ vs. 13％, p＜0.0001 ; epsilon waves, 34％ vs. 14％, p=0.02）. In multivariate analysis, first-degree AVB at baseline was the strongest independent risk factor for HF hospitalization in patients with ARVC（hazard ratio 4.24, p=0.0011）. In conclusion, HF hospitalization has a significant relation with malignant clinical course in ARVC patients.

Objectives : We prospectively examined the validity of a new wristwatch-type pulse wave monitoring device for atrial fibrillation（AF）. Methods : In 84 AF patients（73 paroxysmal and 11 persistent AF, age 70.1 ± 10.0 years）, the new wristwatch-type pulse wave monitoring device（test machine : HC-1, Seiko Epson）and the already-existing Holter monitoring device（SEER-light, GE healthcare）were simultaneously used to record the pulse and electrocardiogram, respectively, for 24 hours. Both of the recordings were separated by 30-min intervals for AF detection（≥30-min persisting AF was counted）. AF burden was compared between the two devices. Results : Among 84 patients, AF was detected in 29 patients by HC-1. Using the Holter monitoring device（AF was detected in 28 patients）as the gold standard, the sensitivity and the specificity of the pulse wave device for detecting AF were 92.8％ and 94.6％, respectively. Among 3660 sections, AF was detected in 682 sections by HC-1. Using the Holter monitoring device（AF was detected in 724 sections）as the gold standard, the sensitivity and specificity of HC-1 were 92.0％ and 99.5％, respectively. The correlation of AF burden between HC-1 and the Holter monitoring device was 0.799. Conclusion : The wristwatch-type pulse wave monitoring device, HC-1, could be worn for a long period of time and could continuously judge the irregularity of pulses which were specific to AF. In that sense, it would be a useful tool to improve the diagnosis of asymptomatic AF.

Purpose : We examined whether the V₁ electrode could be substituted for compound motor action potential（CMAP）recordings. Subjects and Methods : Twenty-six patients with paroxysmal and persistent atrial fibrillation who underwent cryoballoon ablation（CBA）. The cathode was compared with the conventional placement method of 5cm from the xiphoid process to the cranial side and the V₁ method using the V₁ electrode. The right side was recorded from the right subclavian vein or superior vena cava and the left side with a 10V/2ms stimulus and simultaneous CMAP recording. The average potential（mV）of 15 waveforms was evaluated by the Lin coincidence coefficient（CCC）and Bland-Altman plot（BA）by the conventional method and V₁ method. RESULTS : The patients included 37 patients（67.5 years of age［median］ ; 20 males）, 26 right CMAP cases and 11 left CMAP cases. The average potentials using the conventional versus V₁ method were 0.68 ± 0.25 and 0.76 ± 0.27 on the right and 0.74 ± 0.21 and 0.74 ± 0.21 on the left, respectively. For the ％ confidence interval, there was an addition error on the right of－0.076（－0.084 -－0.067）and －0.003（－0.015 - 0.008）on the left. Conclusion : The V₁ electrode could be used with the cathode electrode of CMAP. With this method, the use of the cathode electrode saves cost.

The optimal atrioventricular delay setting in patients with cardiac implantable electronic devices is important for atrioventricular synchronization to maximize the cardiac output. The Echo Doppler method is commonly used for optimizing the AV delay, but is often not performed clinically due to the workload. In this study, we examined the usefulness of the QuickOpt^TM optimization in nine cases with atrioventricular block using the ACECULON mini^Ⓡ. The stroke volume（SV）, stroke index（SI）, cardiac output（CO）, cardiac index（CI）, and index of contractility（ICON）were compared and examined. Compared to the initial AV delay setting and QuickOpt^TM optimization, the sensed AV delay and paced AV delay were significantly shortened in all cases with the QuickOpt^TM optimization. As a result, the SV, SI, CO, CI, and ICON increased significantly in all cases. In conclusion, the QuickOpt^TM optimization could easily adjust the settings to obtain an optimal AV delay, suggesting that the optimal AV delay was shorter than the initial AV delay setting.

Abstract : We reported a patient with high-degree atrio-ventricular block with various QRS complexes. While the ventricular captured beats showed right bundle branch block（RBBB）axis +30°（A）, 2 patterns of escape beats, i.e. RBBB axis +60°（B）and left bundle branch block（LBBB）（C）, were observed with cycle lengths 1.65 and 1.68 sec, respectively. Fusion beats of various degrees between B and C were also observed. When RP interval was＞0.89 sec, the P wave depolarized the escape focus antegradely. When RP interval was ≤0.88 sec, the P wave did not antegradely depolarize the escape focus but retrogradely depolarized it with some delay, conducting via the lower portion of His bundle transversely. QRS axis of B showed mild rightward shift compared with that of A. With the aforementioned electrocardiographic findings, we concluded that His bundle was functionally dissociated into triple pathway. In addition, the P wave conducting through the bundle connecting to the left posterior bundle branch caused A, and two escape focuses localized in the bundles connecting to the left anterior bundle branch and right bundle branch caused B and C, respectively.