Right Ventricular Myocardial Function in Patients with Either Idiopathic or Ischemic Dilated Cardiomyopathy Without Clinical Sign of Right Heart Failure: Effects of Cardiac Resynchronization Therapy

Objective: In dilated cardiomyopathy (DCM), right ventricular (RV) dysfunction has been reported and attributed both to altered loading conditions and to RV involvement in the myopathic process. The aim of the study was to detect RV myocardial function in DCM using two‐dimensional (2D) strain echocardiography and to assess the effects of cardiac resynchronization therapy (CRT) on RV myocardial strain during a 6‐month follow‐up. Methods and Results: A total of 110 patients (mean age: 55.4 ± 11.2 years) with either idiopathic (n = 60) or ischemic (n = 50) DCM, without overt clinical signs of RV failure, underwent standard echo and 2D strain analysis of RV longitudinal strain in RV septal and lateral walls. The two groups were comparable for clinical variables (New York Heart Association class III in 81.8%). Left ventricular volumes, ejection fraction, stroke volume, and mitral valve effective regurgitant orifice were similar between the two groups. No significant differences were evidenced in Doppler mitral and tricuspid inflow measurements. RV diameters were mildly increased in patients with idiopathic DCM, while RV tricuspid annulus systolic excursion and Tei‐index were comparable between the two groups. RV global longitudinal strain and regional peak myocardial strain were significantly impaired in patients with idiopathic DCM compared with those having ischemic DCM (all P < 0.001). Using left ventricular end‐systolic volume as marker for response to CRT, 70 patients (63.3%) were long‐term responders. Ischemic DCM patient responders to CRT showed a significant improvement in RV peak systolic strain. Conversely, in patients with idiopathic DCM and in ischemic patients nonresponders to CRT, no improvement in RV function was evidenced. By multivariable analysis, in the overall population, ischemic etiology of DCM (P < 0.0001), positive response to CRT (P < 0.001), and longitudinal intraventricular dyssynchrony (P <0.01) emerged as the only independent determinants of RV global longitudinal strain after CRT. Conclusions: Two‐dimensional strain represents a promising noninvasive technique to assess RV myocardial function in patients with DCM. RV myocardial deformation at baseline and after CRT are more impaired in idiopathic compared with ischemic DCM patients. Future longitudinal studies are warranted to understand the natural history of RV myocardial function, the extent of reversibility of RV dysfunction with CRT, and the possible prognostic impact of such indexes in patients with congestive heart failure.