Myocardial alterations and clinical implications associated with recovery of cardiac function in dilated cardiomyopathy with obesity

Abstract

Background: Obesity is associated with an increased risk of heart failure (HF) but the relationship between changes in cardiac function and the specific pathological features of dilated cardiomyopathy (DCM) with obesity, remains unknown.

Methods: Endomyocardial biopsies from the left ventricle (LV) were obtained from 50 patients with DCM, at the first-onset of decompensated HF. Thirty patients were obese (obese-group: body mass index >30 kg/m(2)) and 20 were non-obese (lean-group). Clinical data were acquired at the admission, after one month and one year.

Results: The obese-group had higher systolic blood pressure (142.8 ± 33.9 vs 113.6 ± 18.7 mm Hg; p<0.001) and serum troponin-T level (0.049 ± 0.07 vs 0.020 ± 0.03 ng/mL; p=0.022) than the lean-group. LV ejection fraction (LVEF) was not significantly different between groups, but after one year the obese-group had an improved LVEF (57.0 ± 11.4 vs 44.3 ± 17.1; p=0.003). Light microscopy revealed that the obese-group had larger cardiomyocytes (17.2 ± 1.7 vs 16.4 ± 1.4 μm; p=0.033) and less myofilament lysis (37 vs 75%; p=0.008) with a higher density of lipid droplets (1.93 ± 0.8 vs 0.94 ± 0.7 /μm(2); p<0.001). Multivariate regression analysis revealed that independent predictors of LVEF improvement after 12 months were diuretics use, nuclear diameter, and absence of myofilament lysis (p=0.024, 0.012 and 0.028, respectively).

Conclusions: Cardiac function in most patients with DCM with obesity is reversible and myocardial structural changes are trivial even at the ultrastructural level.

Keywords: Dilated cardiomyopathy; Endomyocardial biopsy; Long-term observation; Obesity; Recovery of cardiac function; Ultrastructural myocardial changes.