Exercise testing oversights underlie missed and delayed diagnosis of catecholaminergic polymorphic ventricular tachycardia in young sudden cardiac arrest survivors

Abstract

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is characterized by adrenergically induced ventricular tachycardia, syncope, and sudden cardiac arrest (SCA). In the absence of structural disease, exercise-provoked premature ventricular contractions in bigeminy or couplets and nonsustained ventricular tachycardia are highly predictive of CPVT. The purpose of this study was to determine the number of missed or delayed CPVT diagnoses attributable to exercise testing oversights in a cohort of young SCA survivors. A retrospective review of 101 young SCA survivors (younger than 35 years at the time of SCA) with otherwise structurally normal hearts was used to identify those with a missed or delayed CPVT diagnosis because of overlooked evidence or lack of an exercise stress test (EST) or catecholamine provocation test (CPT) post-SCA. Of the 101 young SCA survivors, 41 (41%) had exertion/emotion-associated SCA (EEA-SCA). After primary post-SCA investigations, a probable root cause was established in 20 of 41 EEA-SCA survivors (49%; CPVT in 8) and in 30 of 60 non-EEA-SCA survivors (50%; CPVT in 2) (P = 1). Only 14 of 21 unexplained EEA-SCA survivors (67%) had an EST/CPT performed before their referral evaluation. Secondary review of these prior ESTs/CPTs provided evidence of CPVT in 3 of 14 (21%). Of the 7 remaining unexplained cases of EAA-SCA who had never undergone an EST/CPT, 2 (29%) underwent their first EST at our institution that led to CPVT diagnosis. Of the 15 SCA survivors diagnosed ultimately with CPVT, one-third had a delay in diagnosis because an EST was either never performed or performed but misinterpreted. EST/CPT must become the standard of care after SCA in the young, especially if the SCA occurred during either exertion or emotion.