INCIDENCE AND CLINICAL-SIGNIFICANCE OF MULTIPLE CONSECUTIVE, APPROPRIATE, HIGH-ENERGY DISCHARGES IN PATIENTS WITH IMPLANTED CARDIOVERTER-DEFIBRILLATORS

Background Some patients with an automatic implantable cardioverter-de fibrillator (ICD) suffer multiple appropriate, consecutive, high-energ y discharges (MCDs) during follow-up. Such events might represent resi stant ventricular arrhythmias and might have prognostic significance. Methods and Results Eighty consecutive patients with an ICD were follo wed up for up to 82 months (mean, 21 +/- 19 months). Thirty-eight pati ents had survived an out-of-hospital cardiac arrest and 42 had recurre nt ventricular tachycardia. During follow-up, 16 patients had MCD (gro up A), 26 patients had episodes of single appropriate discharges (grou p B), and 38 patients had no appropriate discharges (group C). Group A patients had worse functional status (P=.001), lower left ventricular ejection fractions (LVEFs) (P=.001), and lower survival rates (log ra nk, P=.003) than the remaining two groups of patients. Cox analysis sh owed LVEF (P=.001) to be an independent predictor of MCD. Independent predictors of death or heart transplant were MCD (P=.001), female sex (P=.001), age(P=.001), history of cardiac arrest (P=.003), and functio nal status (P=.003). The only independent predictor of total mortality was female sex (P=.002). Independent predictors of cardiac death were MCD (P=.007) and female sex (P=.018). Independent predictors of arrhy thmic death were age (P=.001), female sex (P=.02), and MCD (P=.023). C onclusions In patients with an ICD, the development of MCD is an indep endent predictor of cardiac and arrhythmic mortality. If this finding is confirmed in larger studies, it may help to identify patients in wh om other therapeutic alternatives, ie, heart transplantation, should b e considered during follow-up after ICD implantation.