Abstract 9290: Clinical, Electrocardiographic, and Genetic Characteristics of Patients with Idiopathic Ventricular Fibrillation Associated with Early Repolarization
Background: Early repolarization or J-wave has generally been considered benign for decades. However, we and others recently reported that early repolarization is associated with idiopathic ventricular fibrillation (VF). This study aimed to investigate its clinical and genetic characteristics and to identify risk factors for arrhythmia events.
Methods and results: This study included 38 patients (32 men; age, 42±17 years) with idiopathic VF associated with early repolarization. All of the patients had arrhythmia events. The events occurred during sleeping (n=12) or at rest (n=9) in more than half of the patients. An electrical storm defined as ≥3 episodes of VF during 24 hours was observed in 8 patients (21%). A family history of sudden cardiac death was reported in 7 patients (18%). In 12-lead electrocardiograms, early repolarization was present in the inferior leads in 9 patients, in the lateral/precordial leads in 12 patients, and in both of the inferior and lateral/precordial leads in the remaining 17 patients. Conduction disease, mostly prolongation of PR interval, was present in 13 patients (34%). The heart rate was slower, and the PR interval and QRS duration were longer in patients with idiopathic VF compared to 190 age- and sex-matched healthy controls. VF was inducible by programmed electrical stimulation in 15 of 27 patients (55%). We identified loss-of-function mutations in SCN5A in 3 unrelated patients, and interestingly, His-ventricular interval was prolonged in all of them. During a follow-up of 6.0±5.7 years, VF recurred in 9 patients. Multivariate analyses revealed that a family history of sudden cardiac death and a history of electrical storm were associated with increased risk of arrhythmia recurrences. The age of arrhythmia onset, gender, lead location of early repolarization, activity at the initial event, conduction disease, or inducibility of VF were not associated with the risk of recurrences.
Conclusions: This study showed the clinical and genetic characteristics of idiopathic VF associated with early repolarization, suggesting the underlying mechanism for arrhythmia susceptibility. Our data may be useful for risk stratification for arrhythmia events.
- © 2011 by American Heart Association, Inc.