Clinical characteristics, genetic findings and arrhythmic outcomes of patients with catecholaminergic polymorphic ventricular tachycardia across the globe

Introduction: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare cardiac ion channelopathy. The aim of this study is to examine the genetic basis and identify predictive factors for arrhythmic outcomes of CPVT patients from China. Methods: PubMed and MedRxiv were systematically searched for case reports or case series reporting on CPVT patients from China. Clinical characteristics, genetic findings and primary outcome of spontaneous ventricular tachycardia/ventricular fibrillation (VT/VF) were analyzed. Results: A total of 56 (median presentation age=9 [6-13] years old) patients were included. All patients except for one presented at or before 19 years of age. Fifty-three patients (94.6%) were initially symptomatic. PVCs were present in 40 out of 45 patients (88.9%) and VT in 51 out of 56 patients (91.1%). Genetic tests were performed in 50 patients (89.3%). RyR2, CASQ2 and TERCL mutations were found in 32 (57.1%), 11 (19.6%) and one (0.02%) patients, respectively. Fifty patients were treated with beta-blockers, eight patients received flecainide, four patients received amiodarone, two received verapamil and one received propafenone. Sympathectomy (n=10) and implantable-cardioverter defibrillator implantation (n=7) were performed. On follow-up, 17 patients developed incident VT/VF. Conclusion: This is the first systemic review and meta-analysis of CPVT patients from China. Most patients had symptoms on initial presentation, and around a third had VT as the presenting complaint. RyR2 mutation accounts for more than half of the CPVT cases, followed by CASQ2 and TERCL mutations. Some of these mutations have not been hitherto reported outside of China. Most patients received β-blocker therapy. Around 18% had sympathectomy and 13% had ICDs implanted.