The exercise tolerance dependence on epicardial fat thickness, right ventricular hypertrophy and right ventricular global function in patients with metabolic syndrome

Abstract

Abstract Background The importance of the evaluation of right compartments of the heart is beyond doubts. Right ventricle (RV) plays one of the leading roles in assessing the prognosis of the patients, especially in the context of metabolic syndrome (MS), insulin resistance and visceral obesity. Several trials highlight the epicardial fat thickness (EFT) as a novel marker of visceral obesity and the proximity to the RV does not exclude its direct effect on ventricular function. More of that, EFT represents a metabolically active organ with a wide range of bioeffects that could potentiate cardiometabolic risk profile in patients with MS and visceral obesity. Purpose The objective of the present study was to evaluate the impact of visceral obesity, RV hypertrophy and RV diastolic and global function on exercise capacity (i.e., exercise duration (ED), metabolic equivalents (METs)) in patients with MS and persevered left ventricular function. Methods We included 97 subjects with MS (mean age 54±8.7 years) and 97 controls without MS (mean age 53±9.6 years, P=0.13). MS was defined by ≥3 criteria of International Diabetes Federation and American Heart Association/National Heart, Lung, and Blood Institute. Using 2D echocardiography we assessed RV diastolic function: the ratio of early and late diastolic tricuspid flow velocities (Et/At), the ratio of early diastolic tricuspid flow velocity and early diastolic tricuspid annular velocity (Et/e't), Et deceleration time (DT); Tei index of RV by pulsed tissue Doppler; RV free wall thickness; epicardial fat thickness (EFT). All the participants underwent exercise ECG stress test (cycle ergometry) and the exercise capacity was determined by ED and METs. Results Et/At, Et/e't, EtDT and Tei index were significantly deteriorated in MS group (all P<0.05). Also, RV free wall thickness and EFT showed significant correlations with parameters of RV diastolic function in patients with MS, respectively: Et/At (r=−0.432, P<0.05; r=−0.523, P<0.01), Et/e't (r=0.334, P<0.01; r=0.291, P<0.01), EtDT (r=0.411, P<0.05; r=0.593, P<0.001). RV Tei index positively correlated with RV free wall thickness (r=0.628, P<0.001) and EFT (r=0.623, P<0.001). In bivariate analysis we found that METs were negatively associated to Et/e't (r=−0.208, P=0.033), EtDT (r=−0.295, P<0.01), RV Tei index (r=−0.515, P<0.001), RV free wall thickness (r=−0.504, P<0.001), EFT (r=−0.646, P<0.05) in MS group. Also, ED showed important negative correlation with the same parameters (all P<0.05). Systolic function of RV did not show statistically significant correlations with METs or ED. Multivariate regression analysis showed that RV free wall thickness, RV Tei index and EFT were independently associated with METs in patients with MS (P<0.05). Conclusions Our findings support that epicardial fat thickness, right ventricular Tei index and right ventricular hypertrophy impact exercise tolerance in patients with metabolic syndrome. Funding Acknowledgement Type of funding sources: None.