Early repolarization pattern is the strongest predictor of arrhythmia recurrence in patients with idiopathic ventricular fibrillation: results from a single centre long-term follow-up over 20 years

Abstract

Aims: Idiopathic ventricular fibrillation (iVF) accounts for up to 14% of VF incidence. Data regarding long-term outcome and clinical risk markers of arrhythmia recurrence are scarce. The objective of our study was to describe a long-term follow-up (FU) of a cohort of iVF survivors in our centre during the past 20 years, and to investigate the influence of clinical parameters, e.g. presence of an early repolarization pattern (ERP), on recurrence rate of arrhythmias.

Methods and results: Thirty-five iVF survivors were identified and retrospectively analysed regarding recurrent implantable cardioverter-defibrillator (ICD) interventions and covariates potentially influencing arrhythmia recurrence. Appropriate ICD interventions occurred in 15 patients (43%) after a median of 6.6 years during a median FU period of 8.8 years. Two patients (13%) received the first appropriate therapy after an assumed average ICD battery longevity of 7 years, while in all other patients, the first therapy occurred within the first ICD period. Appropriate interventions were observed more often and earlier in patients with ERP (HR 3.9; 1.4-11.0; P = 0.01), whereas all other covariates failed to predict subsequent events. A high incidence of inappropriate ICD therapies (67 interventions in 14 patients) could be attributed to the occurrence of atrial fibrillation (66% of all inappropriate therapies).

Conclusion: The recurrence rate of ventricular arrhythmias in iVF survivors is high and recurrence might occur delayed (>7 years after the initial event). ERP seems to be highly predictive with respect to early arrhythmia recurrence. Our results highlight that better pathophysiologic understanding of ERP might facilitate a better risk stratification before and an optimal treatment after an iVF event. The high rate of AF and ERP in iVF survivors might indicate an underlying heart disease or myocardial electrical disorder not apparent at the index event.

Keywords: Early repolarization pattern; Early repolarization syndrome; Idiopathic ventricular fibrillation; Sudden cardiac death.