Association of Myocardial Energetic Efficiency with Circumferential and Longitudinal Left Ventricular Myocardial Function in Subjects with Increased Body Mass Index (the FATCOR Study)

Lower myocardial mechanic-energetic efficiency (MEEi), expressed as stroke volume/heart rate ratio (SV/HR) in mL/s/g of the left ventricular (LV) mass, is associated with the incidence of heart failure in subjects with cardiometabolic disorders. We explored the association of MEEi with LV systolic circumferential and longitudinal myocardial function in 480 subjects with increased body mass index (BMI) without known cardiovascular disease (mean age 47 ± 9 years, 61% women, 63% obese, 74% with hypertension) participating in the fat-associated cardiovascular dysfunction (FATCOR) study. Insulin resistance was assessed by the homeostasis model assessment insulin-resistance index (HOMA-IR). SV was calculated by Doppler echocardiography. The LV systolic circumferential myocardial function was evaluated by midwall fractional shortening (MFS) and longitudinal function by global longitudinal strain (GLS). Patients were grouped into MEEi quartiles. The lowest MEEi quartile (<0.41 mL/s per g) was considered low MEEi. The association of MEEi with MFS and GLS were tested in multivariable linear regression analyses. Patients with low MEEi were more frequently men, with obesity and hypertension, dyslipidemia and higher HOMA-IR index (all p for trend <0.05). In multivariable analyses, lower MEEi was associated with lower LV myocardial function by MFS and GLS independent of higher LV mass and clinical variables, including older age, male sex, presence of hypertension and a higher triglycerides level (all p < 0.05). In conclusion, in subjects with increased BMI without known cardiovascular disease participating in the FATCOR study, reduced MEEi was associated with lower LV myocardial function both in the circumferential and longitudinal direction, independent of cardiometabolic factors.