The prognostic significance of the echocardiographic evaluation of left ventricular myocardial deformation indices at peak cardiopulmonary exercise in patients with severe dilated cardiomyopathy

Abstract

Abstract Background Cardiopulmonary exercise testing (CPET) integrally estimates exercise capacity (peak VO2) and cardiovascular (CV) prognosis (VE/VCO2 slope) in patients with dilated cardiomyopathy (DCM). Myocardial deformation indices (MDI), measured by speckle tracking imaging (STI), allow reliable measurements of left ventricular (LV) function. Little is known about the exercise-induced changes of the multidimensional mechanical properties of the heart and their impact in patient's survival. We aimed to investigate the predictive role regarding 3-year survival of LV MDI (at rest and peak exercise) as well as the main CPET parameters (peak VO2, VE/VCO2 slope) in DCM patients with reduced ejection fraction (EF) using as primary combined end-point the heart transplantation and all cause death. Patients and methods We evaluated LV function using STI at rest and at peak exercise during the same CPET session in 53 DCM patients (54±12 years, 76% males, ejection fraction 33±9%).We measured global longitudinal strain (GLS), longitudinal strain rate at systole (LSRS) and diastole (LSRD) at baseline and at peak CPET along with CPET parameters. After a period of 38±15 months, all DCM patients were evaluated by a telephone interview. Results From the whole population, totally 7 patients (13%) reached the primary end-point (Group A) as 2 patients were submitted to heart transplantation and 5 patients died (60±13 years, 86% males, EF = 28±9%) while 46 patients remained alive at 3-year follow-up (Group B, 53±12 years, 74% males, EF = 33±9%). We found that Group A patients had similar age, sex and EF but reduced peak VO2 (p=0.04) and increased VE/VCO2 slope (p=0.004), impaired GLS at baseline and peak exercise (p=0.02 and p=0.04, respectively) as well as LSRS at peak exercise (p=0.05) compared to Group B patients. Conclusions The evaluation of GLS (rest and peak exercise) and LSRS (peak exercise) as systolic indices of LV myocardial deformation adds valuable information regarding CV prognosis in patients with severe idiopathic DCM. A combined baseline work-up protocol consisted of MDI evaluation at rest and exercise plus the CPET indices may characterize the true severity of heart failure in a DCM population. Funding Acknowledgement Type of funding sources: None.