Is electrical storm in ICD patients the sign of a dying heart? Outcome of patients with clusters of ventricular tachyarrhythmias

Background Electrical storm in patients with implanted cardioverter defibri llators (ICDs) is purported to carry an ominous prognosis. Methods and Results We retrospectively compared 40 patients with electrical storm (defined as three or more episodes of ventricular arrhythmia requiri ng ICD therapy in a 24 h period) with those only having isolated appropriat e ICD therapy (n=57) and with patients having no or only inappropriate ICD therapy (n=125). All patients received ICDs for documented sustained VT or VF. There was no significant difference in age, sex, ejection fraction, tot al follow-up time, or underlying heart disease between any of the three gro ups. Patients who had electrical storm received their first appropriate ICD therapy 275 +/- 369 days post-implant (35%;, had storm as their first even t) with storm occurring an average of 599 +/- 710 days post-implant. Patien ts had 1.5 +/- 1.0 storms in total (median=1), with 55 +/- 91 episodes per storm. There were no significant differences in actuarial survival at 5-yea r follow-up between the three groups. Eighty percent of storm patients were alive 5 years post-implant. Conclusion Storm is a common occurrence in ICD patients, can occur at any t ime during the follow-up period, and does not independently confer increase d mortality. (Europace 2000; 2: 263-269) (C) 2000 The European Society of C ardiology.