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We presented a detailed time course of RFCA-associated PV calcification process. Because RFCA-associated PV calcification may progress over time even with a single ablation, long-term caution should be paid in cases of especially extensive ablation and/or patients with stiff LA syndrome., Competing Interests: Authors declare no conflict of interests for this article., (© 2023 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)

Background: The effect of cardiac rehabilitation (CR) on patients undergoing device implantation (DI) for arrhythmias has been reported; however, the implementation status of these patients has not been clarified. This study aimed to verify the implementation status of CR for patients with heart disease who have undergone DI using real-world data., Methods: This was an observational study using a nationwide administrative database associated with the diagnosis procedure combination (DPC) system in Japan (2014-2018). Subjects were patients with heart disease (70 667 cases) who underwent DI during the above scheduled hospitalization period. The overall rate of CR and the background factors of the subjects were verified., Results: The CR rate for patients with heart disease who underwent DI during hospitalization was 23%, and the CR rate for patients with comorbid heart failure who underwent DI was only 32%. It was confirmed that progressing age was associated with a higher CR implementation rate. The lower the Barthel index score at the time of admission, the higher the CR implementation rate., Conclusions: CR was performed for only one-quarter of all the patients during admission for DI and just one-third of the patients for DI with heart failure. Most of these patients were elderly and had a decreased ability to perform activities of daily living. The DPC data are subject to various limitations, and further research is necessary., Competing Interests: The authors have no conflicts of interest to disclose., (© 2022 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)

We reported a case of early S-ICD shock due to the carryover of previously charged energy. Depending on the interval with the preceding event, an early shock may occur for the subsequent event. Especially, in cases where non-sustained VTs occur frequently, the indication for S-ICD surgery should be considered carefully., Competing Interests: The authors declare no conflict of interests for this article., (© 2022 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Heart Rhythm Society.)

Background: An implantable cardioverter defibrillator (ICD) is the most reliable therapeutic device for preventing sudden cardiac death in patients with sustained ventricular tachycardia (VT). Regarding its effectiveness, targeted VT is defined based on the tachyarrhythmia cycle length. However, variations in RR interval variability of VTs may occur. Few studies have reported on VT characteristics and effects of ICD therapy according to the RR interval variability. We aimed to identify the clinical characteristics of VTs and ICD therapy effects according to the RR interval variability., Methods: We analyzed 821 VT episodes in 69 patients with ICDs or cardiac resynchronization therapy defibrillators. VTs were classified as irregular when the difference between two successive beats was >20 ms in at least one of 10 RR intervals; otherwise, they were classified as regular. We evaluated successful termination using anti-tachycardia pacing (ATP)/shock therapy, spontaneous termination, and acceleration between regular and irregular VTs. The RR interval variability reproducibility rates were evaluated., Results: Regular VT was significantly more successfully terminated than irregular VT by ATP. No significant difference was found in shock therapy or VT acceleration between the regular and irregular VTs. Spontaneous termination occurred significantly more often in irregular than in regular VT cases. The reproducibility rates of RR interval variability in each episode and in all episodes were 89% and 73%, respectively., Conclusions: ATP therapy showed greater effectiveness for regular than for irregular VT. Spontaneous termination was more common in irregular than in regular VT. RR interval variability of VTs seems to be reproducible., Competing Interests: This study was financially supported by Medtronic Japan. Dr Satoshi Higa is a consultant to Japan Life Line and Johnson & Johnson and received speaker's honoraria from Japan Life Line, Medtronic, Abbott, Bayer, Biotronik, Boehringer‐Ingelheim, Bristol‐Myers, Daiichi‐Sankyo Pharmaceutical Company, and Pfizer., (© 2021 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of the Japanese Heart Rhythm Society.)

Background: There are no criteria for selecting single- or dual-chamber implantable cardioverter defibrillators (ICDs) in patients without a pacing indication. Recent reports showed no benefit of the dual-chamber system despite its preference in the United States. As data on ICD selection and respective outcomes in Japanese patients are scarce, we investigated trends regarding single- and dual-chamber ICD usage in Japan., Methods: Data from a total of 205 ICD recipients with structural heart disease (median age, 63 years) in two Japanese university hospitals were reviewed. Patients with bradycardia with a pacing indication and permanent atrial fibrillation at implantation were excluded., Results: Single- and dual-chamber ICDs were implanted in 36 (18%) and 169 (82%) patients, respectively. Non-ischemic cardiomyopathy dominated both groups. Seventeen dual-chamber patients developed atrial pacing-dependency over 4.5 years, and it developed immediately after implantation in 14. Although preoperative testing showed no sign of bradycardia in these patients, their pacing rate was set higher than it was in patients who were pacing-independent (61 vs. 46 paces per min, p<0.01). Two single-chamber patients (5%) underwent atrial lead insertion. While inappropriate shock equally occurred in both groups (7 vs. 21 patients, single- vs. dual-chamber, P=0.285), device-related infection occurred only in dual-chamber patients (0 vs. 9 patients, P=0.155). No differences in death or heart failure hospitalization were observed between groups., Conclusions: Dual-chamber ICDs were four-fold more common in Japanese patients without a pacing indication. No benefit over single-chamber ICD was observed. Newly developed atrial pacing-dependency seemed to be limited and could have been overestimated due to higher pacing rate settings in dual-chamber patients.