The liberal use of ICD in patients with life-threatening ventricular arrhythmias has led to questioning the real benefit in different categories of patients and raised the issue of selecting the appropriate candidate and the appropriate mode (single vs dual chamber ICD) particularly in patients with HF. The first ICD was implanted at the Critical Care Center in 1994, since that time over 65 devices have been implanted.This study was designed to follow-up our implanted ICDs and to determine the effect on clinical course and ultimate outcome in terms of frequency of inappropriate therapies, frequency of hospitalization and mortality in pts with dilated cardiomyopathy.In this work we assessed the long-term outcome in a group of 45 pts (40 M, 5 F, mean age 47.4+11.7, range 21-81) who had ICDs implanted over the last 10 years divided into 3 groups. Group A with (normal heart) (n = 10, 8 M, 2 F, mean age 38+13.8 years, range 21-54), group B with (dilated cardiomyopathy) DCM (n = 9, 8 M, 1 F, mean age 36.2+11.7 years, range 22-58), group C with ischemic cardiomyopathy (ICM) (n = 26, 24 M, 2 F, mean age 54.9+11.5 years, range 38-81). Patients were followed-up for a mean period of 3.5+2.3 years (range 0.5+10 years).Data in this study were collected from the filing system in the follow-up clinic, including history, clinical evaluation, echocardiography, assessed before implantation and indication for ICD implantation. Follow up of pts was done by ECG, patient interrogation of frequent hospitalizations (> 3 times) and ICD interrogation for appropriateness of shocks and success rate of therapies. Results: Compared to normal group frequency of hospitalization in DCM group and ICM group increased from 0% to 11.1% to 26.9% respectively. Mortality was higher in ICM group (34.6%) compared to DCM group (22.2%) and normal group (20%). Contrarily, inappropriate discharges was comparable in the 3 groups (30% in normal group vs 22.2% in DCM group vs 23% in ICM group).Conclusion: Our data point to the role of underlying cardiac pathology in determining the clinical course and ultimate outcome of ICD, with normal pts at one end of the spectrum and ICM pts at the other end of the spectrum. The role of ICD is obviously to change sudden cardiac death to non-sudden cardiac death.