Cardiorespiratory fitness and right ventricular mechanics in uncomplicated diabetic patients: Is there any relationship?

Abstract

This study investigated the association between cardiorespiratory fitness and right ventricular (RV) strain in uncomplicated diabetic patients. This cross-sectional study involved 70 controls and 61 uncomplicated patients with type 2 diabetes, who underwent laboratory analysis, comprehensive echocardiographic study and cardiopulmonary exercise testing. RV endocardial and mid-myocardial longitudinal strains were significantly reduced in diabetic subjects (- 27.5 ± 4.2% vs. - 25.3 ± 4.3%, p = 0.004 for endocardial strain; - 25.6 ± 3.5% vs. - 24.1 ± 3.2%, p = 0.012 for mid-myocardial strain). The same was revealed for endocardial and mid-myocardial of RV free wall. There was no difference in RV epicardial strain. VO2 was significantly lower in the diabetic group (27.8 ± 4.5ml/kg/min vs. 21.5 ± 4.2ml/kg/min, p < 0.001), whereas ventilation/carbon dioxide slope was significantly higher in diabetic subjects (25.4 ± 2.9 vs. 28.6 ± 3.3). Heart rate recovery was significantly lower in diabetic patients. HbA1c and global RV endocardial longitudinal strain were independently associated with peak VO2 and oxygen pulse in the whole study population. Diabetes impacts RV mechanics, but endocardial and mid-myocardial layers are more affected than epicardial layer. RV endocardial strain and HbA1c were independently associated with cardiorespiratory fitness in the whole study population. Our findings show that impairment in RV strain and cardiorespiratory fitness may be useful indicators in early type 2 diabetes, prior to the development of further complications.