Dilated Cardiomyopathy With Mid-Range Ejection Fraction at Diagnosis: Characterization and Natural History

11noBackground Limited data are available on mid-range ejection fraction (mrEF) patients with dilated cardiomyopathy. We sought to define the characteristics, evolution, and long-term prognosis of dilated cardiomyopathy patients with mrEF at diagnosis. Methods and Results We analyzed all dilated cardiomyopathy patients consecutively evaluated in the Trieste Heart Muscle Disease Registry from 1988 to 2013. mrEF and reduced ejection fraction (rEF) were defined as baseline left ventricular (LV) ejection fraction values between 40% and 49% and <40%, respectively. All-cause mortality or heart transplantation, sudden cardiac death, or major ventricular arrhythmias were considered as outcome measures. Worsening LV ejection fraction (reduction to <40%) during follow-up was also considered to identify possible predictors of adverse remodeling. Among 812 enrolled patients, 175 (22%) presented with mrEF at presentation. At baseline, as compared with the rEF group, mrEF patients had lower rates of moderate-severe mitral regurgitation and restrictive LV filling pattern. During a median follow-up period of 120 (60-204) months, the mrEF group presented a lower rate of death/heart transplantation (9% versus 36%, P<0.001) and sudden cardiac death or major ventricular arrhythmias (4.5% versus 15%, P