Abstract 14770: Myocardial Scar Predicts Mortality in Patients With Ischemic and Non-ischemic Cardiomyopathy Who Have Undergone Cardiac Resynchronization Therapy (CRT)

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Introduction: Mortality in patients (pts) with cardiomyopathy (CM) remains high despite advances CRT. We sought to determine the effect of myocardial scar, as depicted by cardiac MRI (CMR), on overall mortality in patients with both ischemic (ICM) and non-ischemic cardiomyopathies (NICM) who underwent CRT placement. Methods: We studied 101 pts (48% NICM, age 62 +/- 11, 33% women) who had a CMR pre-CRT. Total scar % was measured and patients were categorized into tertiles: No scar = 0 % scar (43% of pts); moderate scar: >0 but ≤19% scar (25% of pts) and extensive scar: >19% (32% of patients). CRT placement occurred on average 1 year after CMR. Ejection fraction (EF) pre-CRT and more than 6 months post CRT were assessed. Pts were followed up to 14 years for the occurrence of death. Means were compared using T-test and Cox regression survival analysis was used to compare survival among groups. Results: Mean EF pre-CRT was 22.8% (SD=8) and significantly increased post CRT to 31.5% (SD=15); p<0.01. There were 26 deaths over a mean of 5 years (SD +/- 3 years) from time of CRT implant. Patients with ICM had more % scar (mean=24+/-15%) compared to non-ICM (mean=2+/-5%; p<0.01). On univariate survival analysis, EF pre-CRT (HR=0.9, CI=0.87-0.98, p=0.01) and EF post-CRT (HR=0.9,CI=0.93-0.99,p=0.03) were both significantly associated with survival . Death occurred significantly more in patients with ICM (HR=4.8; CI=1.4-16.3; p=0.01) and in those with any % scar compared to no scar (HR = 4.0 CI=1.2-13.5, p=0.02). Compared to those with extensive scar, pts with no scar (HR=0.2; CI=0.1-0.6, p<0.01) and those with moderate scar (HR=0.3; CI=0.1-0.9; p=0.04) had better survival - figure 1. Even after controlling for the etiology of the CM (ICM vs. NICM), total scar % remained predictive of survival (p=0.02). Conclusion: In a population of patients with ICM and NICM who have undergone CRT, patients with more extensive scar had lower survival, even after adjusting for the etiology of the cardiomyopathy.