Epicardial fat, left ventricular strain, and T1-relaxation times in obese individuals with a normal ejection fraction

Abstract

Background Cardiac magnetic resonance (CMR) may detect early signs of cardiomyopathy. Purpose The purpose of this CMR study was to evaluate epicardial fat volume (EFV), T1-relaxation times (T1), and left ventricular (LV) strain in non-obese (<30 kg/m 2 ) and obese (>30 kg/m 2 ) individuals with no other cardiovascular risk factor and with a normal LV ejection fraction (LVEF) to detect early changes of obesity cardiomyopathy. Material and Methods Seventy-five individuals (38 men) without additional cardiovascular risk factors were examined at 1.5 T. EFV was assessed by a 3D-Dixon sequence. A 3(3)3(3)5 MOLLI scheme was used to assess T1 (ms). Myocardial strain (%) was evaluated by longitudinal (LS) and circumferential strain (CS) analysis. Results Obese individuals (n = 34; age = 55.6 ± 13.8 years; BMI = 33.4 ± 2.9 kg/m 2 ) had higher EFVs (70.2 ± 27.9 vs. 56.1 ± 25.2 mL/m 2 ; P < 0.05) and T1 values (991.0 ± 38.6 vs. 974.6 ± 32.0; P = 0.061) as well as worse LS and CS values (LS = −21.0 ± 4.8 vs. −23.2 ± 3.7; CS = −23.8 ± 5.7 vs. −27.7 ± 4.2; P < 0.05, for all) compared to non-obese individuals (n = 41; age = 57.2 ± 15.5 years; BMI = 25.1 ± 2.3 kg/m 2 ). Individuals with severe obesity (BMI > 35 kg/m 2 ) had a significantly higher T1 compared to non-obese (1010.5 ± 39.9 vs. 974.6 ± 32.0 ms; P < 0.05). There were no significant differences regarding age or gender. Conclusion Obesity is associated with an increased EFV and a disturbed LV contractility despite a normal LVEF. Myocardial fibrosis as well as metabolic and inflammatory mechanisms of increased epicardial fat may play role. Multi-parametric CMR may be a valuable tool for the detection of such early signs of an obesity cardiomyopathy.