Association between right ventricular two-dimensional strain and exercise capacity in patients with either idiopathic or ischemic dilated cardiomyopathy

OBJECTIVES: To detect right ventricular myocardial function in dilated cardiomyopathy (DCM) using two-dimensional strain echocardiography (2DSE) and to evaluate the relationship between right ventricular dysfunction and response to cardiopulmonary exercise test (CPET). METHODS: Seventy-five DCM patients (44 idiopathic and 31 ischemic) without clinical signs of right ventricular failure underwent standard echo, 2DSE analysis of right ventricle and bicycle CPET. RESULTS: The two groups were comparable for clinical and standard two-dimensional echocardiographic and Doppler variables, except for right ventricular diameters that were mildly increased in patients with idiopathic DCM. Right ventricular global longitudinal strain (RV GLS) and regional peak myocardial right ventricular strain were significantly impaired in patients with idiopathic DCM compared with ischemic DCM (both P<0.001). A significant correlation was detectable among RV GLS and VO2 peak percentage (r= -0.65, P<0.0001), VE/VCO2 slope (r=0.35, P<0.01), maximum work rate percentage (r= -0.55, P<0.001) and peak circulatory power (r=0.53, P<0.001). These correlations with RV GLS remained significant even in multivariate analysis. CONCLUSION: 2DSE represents a promising noninvasive technique to assess right ventricular myocardial function in patients with DCM. Reduced right ventricular myocardial deformation is related to decreased ability to perform aerobic exercise and work rate, and to impaired ventilatory response.