Introduction: Implantable cardioverter-defibrillators (ICDs) can prevent sudden cardiac death due to ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). The aim of our study was to assess the cumulative burden, evolution and potential triggers of appropriate ICD shocks during long-term follow-up, which may help to reduce and further refine individual arrhythmic risk in this challenging disease., Methods: This retrospective cohort study included 53 patients with definite ARVC according to the 2010 Task Force Criteria from the multicentre Swiss ARVC Registry with an implanted ICD for primary or secondary prevention. Follow-up was conducted by assessing all available patient records from patient visits, hospitalisations, blood samples, genetic analysis, as well as device interrogation and tracings., Results: Fifty-three patients (male 71.7%, mean age 43±2.2 years, genotype positive 58.5%) were analysed during a median follow-up of 7.9 (IQR 10) years. In 29 (54.7%) patients, 177 appropriate ICD shocks associated with 71 shock episodes occurred. Median time to first appropriate ICD shock was 2.8 (IQR 3.6) years. Long-term risk of shocks remained high throughout long-term follow-up. Shock episodes occurred mainly during daytime (91.5%, n=65) and without seasonal preference. We identified potentially reversible triggers in 56 of 71 (78.9%) appropriate shock episodes, the main triggers representing physical activity, inflammation and hypokalaemia., Conclusion: The long-term risk of appropriate ICD shocks in patients with ARVC remains high during long-term follow-up. Ventricular arrhythmias occur more often during daytime, without seasonal preference. Reversible triggers are frequent with the most common triggers for appropriate ICD shocks being physical activity, inflammation and hypokalaemia in this patient population., Competing Interests: Competing interests: AMS received educational grants through his institution from Abbott, Bayer Healthcare, Biosense Webster, Biotronik, Boston Scientific, BMS/Pfizer, Medtronic and Novartis, and speaker/consultant fees from Bayer Healthcare, Biotronik, BMS/Pfizer, Daiichi-Sankyo, Medtronic, Novartis and Stride Bio. DH reports educational grants, consultant or speaker fees and fellowship support from Abbott, Bayer, Biotronik, Biosense Webster, Boston Scientific, Medtronic, Novartis, Pfizer and Spectranetics/Philips. AB has received consultant and/or speaker fees from Abbott, Bayer Healthcare, Biosense Webster, Biotronik, Boston Scientific, Bristol-Myers Squibb, Cook Medical, Daiichi Sankyo, Medtronic, Pfizer, Spectranetics/Philipps and ZOLL. AM-D is the founder of SwissDNAlysis. FR has not received personal payments by pharmaceutical companies or device manufacturers in the last 3 years (remuneration for the time spent in activities, such as participation as steering committee member of clinical trials and member of the Pfizer Research Award selection committee in Switzerland were made directly to the University of Zurich). The Department of Cardiology (University Hospital of Zurich/University of Zurich) reports research, educational and/or travel grants from Abbott, Amgen, Astra Zeneca, Berlin Heart, B. Braun, Biosense Webster, Biosensors Europe AG, Biotronik, BMS, Boehringer Ingelheim, Boston Scientific, Bracco, Cardinal Health Switzerland, Corteria, Daiichi, Diatools AG, Edwards Lifesciences, Guidant Europe NV (BS), Hamilton Health Sciences, Kaneka Corporation, Kantar, Labormedizinisches Zentrum, Medtronic, MSD, Mundipharma Medical Company, Novartis, Novo Nordisk, Orion, Pfizer, Quintiles Switzerland Sarl, Roche Diagnostics, Sahajanand IN, Sanofi, Sarstedt AG, Servier, SIS Medical, SSS International Clinical Research, Terumo Deutschland, Trama Solutions, V-Wave, Vascular Medical, Vifor, Wissens Plus and ZOLL. The research and educational grants do not impact on FR's personal remuneration. The other authors have nothing to disclose related to the content of this article., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)