ABSTRACT
Some patients receive multiple appropriate shocks during a short period of time, arrhythmic electrical storm (malignant ventricular arrhythmias resulting in device intervention > or = 3 times during 24 hours). It is a common implantable cardioverter-defibrillator therapy-related complication. The objectives of this study were to determine the incidence, characteristics, prognostic implications and therapeutic options of electrical storm. This six years prospective study comprised 115 device recipients, who were followed for 510-2,100 days. Electrical storm occurred in 18.3% at 336 days (median) after the implantation, due to diverse causes. The patients with electrical storm had 12 arrhythmic episodes and 9 shocks (median) per electrical storm; 46.6% had more than one storm corresponding to the first recurrence in 60%. There were no deaths. Two additional control groups (with recurrences or not but without storm) were studied. Electrical storm was responsible for more frequent readmissions to the hospital as compared to the controls. The arrhythmic cluster could be terminated by a combined and individualized therapy (amiodarona and beta blockers specially); antitachycardia pacing was better tolerated than shocks. Arrhythmic storm represents a frequent, serious and unpredictable event in patients with implantable cardioverter-defibrillator. It occurrs early or late after the implantation and can be managed by combined therapy. It does not independently increase mortality.