THE IMPACT OF MYOCARDIAL SCAR BY CARDIAC MAGNETIC RESONANCE IN PATIENTS WITH NONISCHEMIC DILATED CARDIOMYOPATHY REFERRED FOR AN IMPLANTABLE CARDIOVERTER DEFIBRILLATOR FOR PRIMARY PREVENTION OF SUDDEN CARDIAC DEATH

Background: Patients with non-ischemic dilated cardiomyopathy NIDC are at risk of arrhythmias and sudden cardiac death (SCD). The likely arrhythmia substrate is myocardial ibrosis. We tested the hypothesis that the presence and extent of ibrosis characterized by late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) may help risk stratify patients with NIDC referred for an implantable cardioverter deibrillator (ICD) therapy for primary prevention of SCD. Methods: One hundred and nine patients ((61% male, mean age of 50±14 years, mean left ventricular ejection fraction of 25±9%) with a class 1 indication for ICD insertion for primary prevention of SCD at two institutions underwent an LGE-CMR study and were prospectively followed. Events of interest were deined as a combination of death and appropriate ICD therapy. Results: Myocardial ibrosis by LGE-CMR was identiied in 59 patients (54%). During the median follow-up period of 34 months there were 30 events (10 deaths and 20 appropriate ICD therapies). Univariate analysis showed that the presence and the extent of LGE demonstrated the strongest unadjusted association with cardiac events (LGE, hazard ratio (HR): 5.8, chi-squared 12.7, P 5.6% had an overall event rate of 23% per year. Conclusions: LGE is a powerful marker of risk in patients with NIDC who meet criteria for ICD insertion.