Myocardial Contraction Fraction is Superior to Ejection Fraction in Predicting Functional Capacity in Patients with Heart Failure with Reduced Ejection Fraction

OBJECTIVES: In this study, we aimed to evaluate the relationship between three-dimensional echocardiography (3DE)-determined myocardial contraction fraction (MCF) and functional capacity in heart failure with reduced ejection fraction (HFrEF) patients. The MCF is a volumetric index of myocardial function, defined as stroke volume ratio to myocardial volume (MV). Functional capacity was evaluated by a 6-min walk test (6MWT), and health-related quality of life (HRQOL) was assessed by the Minnesota Living with Heart Failure Questionnaire (MLHFQ). In view of cardiac remodeling, we hypothesized that MCF would be superior to left ventricular ejection fraction (LVEF) in predicting functional capacity in HFrEF patients. METHODS: The study was conducted on thirty HFrEF patients with an LVEF of no more than 40% with NYHA functional class I–III. Each patient performed, on the same day, the MLHFQ, 6MWT (to calculate the 6-min walk distance “6MWD”), and an ECG gated echocardiographic study including 3DE-determined MCF. MV was calculated as 3DE determined LV mass divided by the specific gravity of the myocardium. RESULTS: Our results showed that MCF is inversely correlated with the Minnesota score (r 0.6, p < 0.001) and positively correlated with 6MWD (r 0.65, p < 0.001). However, no significant relationship existed between LVEF and MLHFQ score or 6MWD. In a multivariate model, MCF was shown to be an independent echocardiographic predictor (besides pulmonary artery systolic pressure) of 6MWD; however, LVEF failed to offer such potential. CONCLUSION: Among various echocardiographic parameters, MCF can be considered a volumetric index superior to LVEF in predicting functional capacity in HFrEF patients.