Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) Associated With Ryanodine Receptor (RyR2) Gene Mutations - Long-Term Prognosis After Initiation of Medical Treatment

Background: The long-term prognosis of cardiac ryanodine receptor (RyR2) positive catecholaminergic polymorphic ventricular tachycardia (CPVT) patients after initiation of medical therapy has not been well investigated. This study aimed to assess the recurrence of fatal cardiac event after initiation of medical therapy in RyR2-positive CPVT patients. Methods and Results: Thirty-four RyR2-positive CPVT patients with a history of cardiac events were enrolled. All patients had medical treatment initiated after the first symptom or diagnosis. Exercise stress tests (ESTs) were performed to evaluate the efficacy of the medical therapy. Even after the initiation of medical therapy, high-risk ventricular arrhythmias (VAs), including premature ventricular contraction couplets, bigeminy, and ventricular tachycardia, were still induced in the majority of patients (80.6%). During 7.4 years of follow-up after the diagnosis, 7 of the 34 (20.6%) patients developed fatal cardiac events. Among those 7 patients, 6 (85.7%) were not compliant with either exercise restriction or medication therapy at the time of the events. Conclusions: Even after initiation of medical treatment, high-risk VAs were induced during EST in most RyR2-positive CPVT patients. Most fatal recurrent cardiac events occurred in patients who were noncompliant with exercise restriction and/or medical therapy. Medical management including strict exercise restriction should be emphasized to prevent recurrent cardiac event in most RyR2-positive CPVT patients.