Left ventricular function and exercise performance in idiopathic dilated cardiomyopathy: role of tissue Doppler imaging

To examine the relationship between left ventricular (LV) function evaluated at echocardiography and exercise performance in idiopathic dilated cardiomyopathy (IDCM) patients.We enrolled 76 consecutive IDCM patients in sinus rhythm, undergoing cardiopulmonary exercise testing and echocardiography [49 ± 13 years old; LV ejection fraction 31 ± 7%, LV end-diastolic volume 96 ± 31 ml/m; peak oxygen consumption (peak VO2/kg) 18 ± 5.6 ml/kg/min]. Linear regression analysis revealed that peak systolic velocity (S') (r = 0.46; P < 0.001) and E/E' (r = -0.43; P < 0.001), two tissue Doppler imaging derived parameters, were related to peak VO2/kg, whereas ejection fraction and mitral inflow variables were not. Considering the 69 patients (90%) without diastolic restrictive pattern (a well known index of severe diastolic dysfunction), multivariate regression analysis showed that age, E/E' and S' were the only independent variables related to peak VO2/kg. Similarly, age and E/E' were confirmed as independent parameters for the prediction of ventilation/carbon dioxide production slope in the whole population.In IDCM patients, cardiopulmonary exercise performance variables were strongly related to E/E' and S'.