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

Abstract

Background: 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.

Objective: 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.

Methods: 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.

Results: 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.

Conclusion: 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.

Keywords: CPVT; Idiopathic ventricular fibrillation; Long QT syndrome; SCA; SCD.