Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia syndrome caused by abnormal calcium handling that is characterized by adrenergically-triggered ventricular arrhythmias (VAs), syncope, and sudden cardiac death. In addition to VAs, several small studies suggest that atrial arrhythmias (AAs) are also observed commonly in CPVT patients.
Objective: To determine the incidence and type of AAs observed within a large, single-center cohort of genetically-confirmed CPVT cases as well as the efficacy and durability of conventional pharmacologic and ablation therapies.
Methods: In this retrospective study, the electronic medical record of 129 patients diagnosed with genetically-confirmed CPVT between 01/2000 and 09/2019 [52% female; average age at diagnosis 20.8 ± 15.3 years; and 95% with a putative CPVT1-causative RYR2 variant(s)] were reviewed for electrocardiographic evidence of AAs, including atrial fibrillation (AF), atrial flutter (AFL), atrial tachycardia (AT), and supraventricular tachycardia (SVT). In those CPVT patients with documented AAs, the type of AA, symptoms, and efficacy of pharmacologic and ablation therapy was assessed.
Results: Overall, 10 out of 129 (7.8%) CPVT patients, all RYR2 variant-positive, had documented evidence of an AA (AF/AFL in 6, AT in 3, and SVT in 1). The median (IQR) age at AA diagnosis was 23 (14.2-35.5) years. 8/10 (80%) of patients experienced symptoms attributed to their AA, including inappropriate shocks. All of these patients were trialed on anti-arrhythmics, including β-blockers, and/or flecainide. Ultimately, owing to drug failure (1/10; 10%), drug intolerance (1/10; 10%), or patient/provider preference (2/10; 20%); 4/10 (40%) of CPVT patients with AAs received radiofrequency (RF) ablation. Notably, over a median (IQR) follow-up duration of 23.5 (4.5-63) months, no AA recurrence was observed.
Conclusion: In comparison to prior small studies, the incidence of AAs in this large, single-center referral cohort of genetically-confirmed CPVT patients was substantially lower (7.8% vs. 26%-35%). Although a larger multi-center study is needed to confirm, this study suggests that conventional RF ablation is both efficacious and durable in CPVT-associated AA.