Incidence and Risk Factors of Arrhythmic Events in Catecholaminergic Polymorphic Ventricular Tachycardia

TLDR

Catecholaminergic polymorphic ventricular tachycardia’s pathophysiology is known, but its clinical incidence and risk factors for arrhythmic events remain unclear. The study aims to identify additional therapies that could improve outcomes in catecholaminergic polymorphic ventricular tachycardia patients. The authors analyzed outcomes in 101 patients, including 50 probands, to assess arrhythmic event incidence. During 7.9‑year follow‑up, 32 % of patients experienced arrhythmic events, with β‑blocker use reducing the 8‑year event rate from 58 % to 27 %; lack of β‑blockers and younger age independently predicted events, and fatal events occurred in 13 % of patients.

Abstract

Background— The pathophysiological background of catecholaminergic polymorphic ventricular tachycardia is well understood, but the clinical features of this stress-induced arrhythmic disorder, especially the incidence and risk factors of arrhythmic events, have not been fully ascertained. Methods and Results— The outcome in 101 catecholaminergic polymorphic ventricular tachycardia patients, including 50 probands, was analyzed. During a mean follow-up of 7.9 years, cardiac events defined as syncope, aborted cardiac arrest, including appropriate discharges from implantable defibrillators, or sudden cardiac death occurred in 27 patients, including 2 mutation carriers with normal exercise tests. The estimated 8-year event rate was 32% in the total population and 27% and 58% in the patients with and without β-blockers, respectively. Absence of β-blockers (hazard ratio [HR], 5.48; 95% CI, 1.80 to 16.68) and younger age at diagnosis (HR, 0.54 per decade; 95% CI, 0.33 to 0.89) were independent predictors. Fatal or near-fatal events defined as aborted cardiac arrest or sudden cardiac death occurred in 13 patients, resulting in an estimated 8-year event rate of 13%. Absence of β-blockers (HR, 5.54; 95% CI, 1.17 to 26.15) and history of aborted cardiac arrest (HR, 13.01; 95% CI, 2.48 to 68.21) were independent predictors. No difference was observed in cardiac and fatal or near-fatal event rates between probands and family members. Conclusions— Cardiac and fatal or near-fatal events were not rare in both catecholaminergic polymorphic ventricular tachycardia probands and affected family members during the long-term follow-up, even while taking β-blockers, which was associated with a lower event rate. Further studies evaluating concomitant therapies are necessary to improve outcome in these patients.