Incidence, Predictors and Clinical Impact of Ventricular Electrical Storm in Arrhythmogenic Cardiomyopathy Patients with an Implantable Cardioverter–Defibrillator: A Single-Center Report with Medium-Term Follow-Up

BACKGROUND: Implantable cardioverter-defibrillator (ICD) is the most effective strategy for prevention of ventricular tachyarrhythmia in patients with arrhythmogenic cardiomyopathy (ACM). However, some patients receive ventricular electrical storm (VES), characterized by multiple episodes of sustained ventricular tachyarrhythmia. The purpose of this study was to determine the incidence, predictors and prognostic implications of VES in ACM patients with an ICD. METHODS: A total of 88 patients with definite ACM who received an ICD and followed up continuously were included in this study. VES was defined as the occurrence of ≥3 separate episodes of sustained ventricular arrhythmias within a 24-hour period. RESULTS: During a median follow-up time of 4.0 years (range 1.6-6.9), VES occurred in 19/88 patients (21.6%). The interval between the ICD implantation and the first VES ranged from 1 month to 128 months. The median number of ventricular tachyarrhythmia events per VES was 7.5 (range 3-32). Multivariate analysis showed that VES was associated with a high body mass index (BMI) [adjusted hazard ratio (HR) 1.21, 95% confidence interval (CI) 1.00-1.45, P=0.048)] and extensive T-wave inversion (TWI) (HR 23.39, 95% CI 1.74-314.58, P=0.017). Kaplan-Meier method showed that patients with VES did not have a worse cardiac mortality compared to those without such an event. CONCLUSION: There is a relatively high incidence of VES in ACM patients. The presence of high BMI and extensive TWI were strong predictors of VES occurrence in ACM patients with ICD. VES does not independently confer increased cardiac mortality.