Rates and predictors of appropriate implantable cardioverter-defibrillator therapy delivery: Results from the EVADEF cohort study

Background The implantable cardioverter defibrillator (ICD) is the therapy of choice in patients at risk for sudden cardiac death in both primary and secondary prevention indication. There are no recent data concerning the delivery rate and etiology of appropriate ICD therapies in routine medical care. Methods The EVADEF study was a French multicenter, prospective, observational cohort study of ICD patients with a 2-year follow-up. Every 6 months we recorded patients' survival status and evaluated appropriate ICD therapies-antitachycardia pacing or shocks. Causes of ICD activation were also recorded from among ventricular tachycardia (VT), fast VT and ventricular fibrillation (VF). Results From 2001 to 2003, 2296 unselected patients were implanted and followed until 2005. During a mean follow-up of 20.5 months, 274 deaths occurred. In 2009 patients with cardiopathy, 22 patients per 100 person-years had at least one appropriate therapy. Twenty-four and 11 patients per 100 person-years had at least one therapy in secondary and primary prevention, respectively. Age >65 years, left ventricular ejection fraction <30% and secondary prevention were independently associated with appropriate therapy. Besides, 5 patients per 100 person-years had at least I episode of life-threatening arrhythmia (fast VT or VF). Left ventricular ejection fraction <30% and secondary prevention were independently associated with life-threatening arrhythmia. In 287 patients without cardiopathy, the rate of appropriate therapy was twice as less, whereas the rate of life-threatening arrhythmia was similar. Conclusion Over a 24-month follow-up, the rate of appropriate therapy was substantial while few patients had life-threatening arrhythmia. Appropriate therapies and life-threatening arrhythmia were more frequent in patients with secondary prevention indication. (Am Heart J 2009;158:230-7.)