Multicenter prospective observational study to clarify the current status and clinical outcome in Japanese patients who have an indication for implantable cardioverter defibrillator (ICD) or wearable cardioverter defibrillator (WCD) (TRANSITION JAPAN-ICD/WCD study): Rationale and design of a prospective, multicenter, observational, comparative study.

Background: Despite the positive impact of implantable cardioverter defibrillators (ICDs) and wearable cardioverter defibrillators (WCDs) on prognosis, their implantation is often withheld especially in Japanese heart failure patients with reduced left ventricular ejection fraction (HFrEF) who have not experienced ventricular tachycardia (VT) or ventricular fibrillation (VF) for uncertain reasons. Recent advancements in heart failure (HF) medications have significantly improved the prognosis for HFrEF. Given this context, a critical reassessment of the treatment and prognosis of ICDs and WCDs is essential, as it has the potential to reshape awareness and treatment strategies for these patients.
Methods: We are initiating a prospective multicenter observational study for HFrEF patients eligible for ICD in primary and secondary prevention, and WCD, regardless of device use, including all consenting patients. Study subjects are to be enrolled from 31 participant hospitals located throughout Japan from April 1, 2023, to December 31, 2024, and each will be followed up for 1 year or more. The planned sample size is 651 cases. The primary endpoint is the rate of cardiac implantable electronic device implementation. Other endpoints include the incidence of VT/VF and sudden death, all-cause mortality, and HF hospitalization, other events. We will collect clinical background information plus each patient's symptoms, Clinical Frailty Scale score, laboratory test results, echocardiographic and electrocardiographic parameters, and serial changes will also be secondary endpoints.
Results: Not applicable.
Conclusion: This study offers invaluable insights into understanding the role of ICD/WCD in Japanese HF patients in the new era of HF medication.
Competing Interests: YOk received research funding from Bayer Healthcare and Biosense Webster, Inc, and received scholarship grant from Boston Scientific Japan, and received speaker honoraria from Daiichi‐Sankyo, Bayer Healthcare, and Bristol‐Meyers Squibb, Ono Pharmaceutical, and Medtronic Japan, and affiliated with endowed courses from Boston Scientific Japan, Japan Lifeline, Fukuda Denshi, Abbott Medical Japan, BIOTRONIK Japan, and Medtronic Japan. RKo is affiliated with an endowed division supported by BIOTRONIK Japan, Abbott Medical Japan, Japan Lifeline and Medtronic Japan. KN received research funding from Johnson & Johnson K.K. TN received lecture fees from Abbott Medical Japan, Medtronic Japan, and BIOTRONIK Japan. TKat received lecture fees from Daiichi‐Sankyo, Bristol‐Myers Squibb, Bayer Healthcare, Boston Scientific Japan, Abbott Japan, Nihon Kohden and Medtronic Japan. HF received speaker honoraria from Daiichi‐Sankyo, Bayer Yakuhin, Nippon Boehringer Ingelheim, Johnson & Johnson K.K., Abbott Medical Japan, Medtronic Japan and Japan Lifeline. SK received research funding from Johnson & Johnson K.K. SN received speaker honoraria from Bayer Healthcare, Daiichi‐Sankyo, Bristol‐Meyers Squibb and Medtronic Japan. MH received research funding from BIOTRONIK Japan, Medtronic Japan, Abbott Medical Japan, Japan Lifeline, Nihon Kohden and Boston Scientific Japan, and received speaker honoraria from Nippon Boehringer Ingelheim, Daiichi‐Sankyo, Bristol‐Meyers Squibb, Medtronic Japan, Japan Lifeline, and Abbott Medical Japan. MM received speaker honoraria from Medtronic Japan and Boston Scientific Japan. WS received grants from Daiichi Sankyo and Nippon Boehringer Ingelheim, and received remuneration for lectures, presentations, speakers bureaus, manuscript writing or educational events from Daiichi Sankyo, Nippon Boehringer Ingelheim, Bristol‐Meyers Squibb, K.K., Bayer Yakuhin, Pfizer, Ono Pharmaceutical and Medtronic Japan. KKu received speaker honoraria from Daiichi‐Sankyo, Ltd., Bayer Yakuhin, and Medtronic Japan, and received research grants from Medtronic Japan, HITACHI, and JSR. KI received speaker honoraria from Medtronic Japan and BIOTRONIK Japan. TH received speaker honoraria from Medtronic Japan, BIOTRONIK Japan and Bayer Yakuhin. IN has received speaking honoraria from Medtronic Japan. MS is affiliated with an endowed division supported by BIOTRONIK Japan, Boston Scientific Japan K.K, Medtronic Japan and Abbott Medical Japan. SHi is affiliated with an endowed division supported by BIOTRONIK Japan, Boston Scientific Japan K.K., Medtronic Japan and Abbott Medical Japan. IM received speaker honoraria from Daiichi‐Sankyo and Abbott Medical Japan. RKa received speaker honoraria from Daiichi‐Sankyo and Medtronic Japan, and received research grants from Boston Scientific Japan and Abbott Medical Japan. YIked received speaker honoraria from Bayer Yakuhin and Medtronic Japan. KKa has received research grants from Omron Healthcare Co., Ltd., A&D Co., Ltd., and Fukuda Denshi Co., Ltd. SS is affiliated with an endowed division supported by BIOTRONIK Japan, and received speaker honoraria from Medtronic Japan, Abbott Medical Japan, BIOTRONIK Japan, Boston Scientific Japan, and Japan Lifeline. YKo received speaker honoraria from Daiichi‐Sankyo, Bayer, Abbott Medical Japan, BIOTRONIK Japan, Boston Scientific Japan, Japan Lifeline, and received research funding from Daiichi‐Sankyo. KM has received honoraria for Chugai Pharmaceutical, AstraZeneca, Taiho Pharmaceutical, MSD, Kyowa Kirin, Yakult Pharmaceutical, and Boehringer Ingelheim. Other authors have no conflict of interest.
(© 2024 The Authors. Journal of Arrhythmia published by John Wiley & Sons Australia, Ltd on behalf of Japanese Heart Rhythm Society.)