Clinical Characteristics, Genetic Findings and Arrhythmic Outcomes of Patients with Catecholaminergic Polymorphic Ventricular Tachycardia from China

Introduction: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare cardiac ion channelopathy. This study examined the clinical characteristics, genetic basis, and arrhythmic outcomes of CPVT patients from China. Methods: PubMed and EMBASE were systematically searched for case reports or series reporting on CPVT patients from China until February 19th, 2022 using the keyword “Catecholaminergic Polymorphic Ventricular Tachycardia” OR “CPVT”, with the location limited to “China” OR “Hong Kong” or “Macau” in EMBASE, with no language or publication type restriction. Clinical characteristics, genetic findings, and primary outcome of spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF) were analyzed. Results: A systematic search of the PubMed and Embase databases yielded 1049 and 47 articles, respectively. After the exclusion of overlapping cohorts, a total of 58 unique cases from 15 studies (median presentation age: 8 [5.0-11.8] years old) were included. All patients except for one presented at or before 19 years of age. 56 patients (96.6%) were initially symptomatic. Premature ventricular complexes (PVCs) were present in 44 of 51 patients (86.3%) and VT in 52 of 58 patients (89.7%). Genetic tests were performed on 54 patients (93.1%) with a yield of 87%. RyR2, CASQ2, TERCL, and SCN10A mutations were found in 35 (71.4%), 12 (24.5%), one (0.02%) patient, and one patient (0.02%) respectively. 54 patients were treated with beta-blockers, eight received flecainide, five received amiodarone, two received verapamil and one received propafenone. Sympathectomy (n=10) and implantable-cardioverter defibrillator implantation (n=8) were performed. On follow-up, 13 patients developed VT/VF. Conclusion: This is the first systematic review of CPVT patients from China. Most patients had symptoms on initial presentation, with syncope as the presenting complaint. RyR2 mutation accounts for more than half of the CPVT cases, followed by CASQ2, TERCL and SCN10A mutations.