Predictors of electrical storm recurrences in patients with implantable cardioverter-defibrillators

Abstract

Aims: To determine prevalence and predictors of electrical storm recurrences (ES-Rs) in patients with implantable cardioverter-defibrillators (ICDs) as electrical storms (ESs) represent serious clinical events carrying a high risk of mortality. Methods and results: Single-centre study analysing data of consecutive patients receiving an ICD between 1993 and 2008. Electrical storm was defined as <3 separate ventricular tachyarrhythmic (VT/VF) episodes ≤24 h. Nine hundred and fifty-five patients [mean left ventricular ejection fraction (LVEF) 35.7 ± 15.6] were prospectively followed for 54.2 ± 35.5 months. In 274 of 955 patients (28.7), 2871 VT/VF episodes were observed. One hundred and fifty-three ES episodes occurred in 63 of 955 patients (6.6). Thirty-two of 63 patients (50.8) experienced <2 ES episodes. Twenty-six of 32 patients (81.2) with ES-Rs experienced the second ES episode within 1 year after the initial event. Cox regression analysis identified an LVEF ≤30 (OR 2.2; 95 CI 1.0214.856; P 0.044) and a patients age >65 years (OR 3.5; 95 CI 1.20710.176; P 0.021) to be predictive for ES-Rs. Patients with angiotensin-converting enzyme (ACE) inhibitor therapy were less likely to experience ES-Rs (OR 0.39; 95 CI 0.1870.817; P 0.013). Conclusions: Electrical storm events are not rare in a 'real-world' patient population with ICDs (6.6 in 4.5 years). The risk for ES-Rs, especially within the first year after the initial event, is high. Left ventricular ejection fraction ≤30, age >65 years, and a lack of ACE inhibitor therapy are independent predictors of ES-R. All rights reserved. © The Author 2010.