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

BACKGROUND: To examine the relationship between left ventricular (LV) function evaluated at echocardiography and exercise performance in idiopathic dilated cardiomyopathy (IDCM) patients. METHODS AND RESULTS: 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. CONCLUSION: In IDCM patients, cardiopulmonary exercise performance variables were strongly related to E/E' and S'.