Background: Delayed enhancement (DE) on cardiac magnetic resonance imaging (CMR) is a marker of myocardial fibrosis. The absence of DE in CMR is a predictor of left ventricular (LV) functional improvement in patients with non-ischemic cardiomyopathy (NICM), so in the present study it was investigated whether presence of DE has prognostic significance in patients with NICM at long-term follow-up.
Methods and results: The 79 patients (56.4+/-13.5 years, 48 males) with NICM (LV ejection fraction <35%, no significant coronary artery disease) were monitored for occurrence of cardiac events. CMR was performed to assess DE. Cardiac events were defined as rehospitalization (because of worsening of heart failure), cardiac transplantation or death. There were 37 patients without and 42 patients with DE. The mean follow-up duration was 19+/-10 months. There was 1 event (2.7%, 1 rehospitalization) in the DE (-) group, whereas 13 events (30.9%, 1 death, 1 transplantation, 11 rehospitalizations) occurred in the DE (+) group. The event-free survival was significantly longer in the DE (-) group than in the DE (+) group (38.9+/-1.0 vs 28.4+/-2.7 months, P<0.01). Multivariate regression analysis revealed that presence of DE was the most potent, independent predictor of cardiac events (hazard ratio 8.06, confidence interval 1.03+/-63.41, P<0.05).
Conclusions: The presence of DE in CMR is a significant predictor of future cardiac events in patients with NICM.