We investigated the prognostic role of myocardial fibrosis by delayed enhancement (DE) cardiovascular magnetic resonance (CMR) in nonischemic dilated cardiomyopathy (NICM) patients with no or mild symptoms of heart failure (HF).
A prospective cohort of 125 NICM patients (82 males, age 59±14years, mean±SD) with echocardiographic evidence of left ventricular (LV) systolic dysfunction (mean ejection-fraction 33±10%), without (stage B) or with history of mild HF symptoms (stage C, NYHA classes I-II) was enrolled. The end-point was a composite of cardiac death and HF hospitalization.
Fifty (40%) patients showed myocardial DE, representing 12±7% of LV mass. During a median follow-up of 14.2months, 16 (32%) patients with DE experienced a composite event versus only 6 (8%) patients without DE (Kaplan-Meier survival curve, p=0.001). After correction for age, CMR-derived LV and right ventricular volumes, echocardiographic measurements of LV diastolic function and Doppler-estimated systolic pulmonary artery pressure, the presence of DE remained a strong and independent predictor of cardiac death or HF hospitalization (hazard ratio: 5.32, 95% confidence intervals 1.60 to 17.63, p=0.006).
In NICM patients with no or mild HF symptoms, the presence of myocardial DE is a strong predictor of worse clinical outcome even after correction for other established prognostic determinants. Contrast-enhanced CMR may be useful in prognostic stratification from the early stages of NICM.