Patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) may experience serious arrhythmic events while receiving beta-adrenergic receptor blocker therapy (beta blockers), complicating individualized risk assessment during follow-up. In the European Heart Journal, externally validated risk prediction models were reported for arrhythmic events in patients with CPVT treated with beta blocker monotherapy.

This observational prognostic modeling study included a derivation cohort of 743 patients and an independent validation cohort of 129 patients with CPVT mediated by ryanodine receptor 2 (RYR2) variants. All patients received beta blockers alone. Arrhythmic events were defined as arrhythmic syncope, appropriate implantable cardioverter-defibrillator shock, sudden cardiac arrest, or sudden cardiac death. Near-fatal or fatal arrhythmic events excluded arrhythmic syncope. Cox proportional hazards regression models were developed and internally and externally validated.

Over a median follow-up of 5.1 years in the derivation cohort and 2.4 years in the validation cohort, arrhythmic events occurred in 13.7% and 18.6% of patients, respectively. Prior arrhythmic syncope or sudden cardiac arrest and age at beta blocker initiation independently predicted arrhythmic events. Model discrimination for arrhythmic events yielded optimism-corrected C-indices of 0.67 and 0.59 in the derivation and validation cohorts. For near-fatal or fatal arrhythmic events, inclusion of ventricular arrhythmia severity before beta blocker initiation yielded C-indices of 0.74 and 0.60, with calibration slopes of 1.00 in the derivation cohort.

These models distinguished lower and higher arrhythmic risk among patients with CPVT treated with beta blocker monotherapy.