Bi-ventricular contractile reserve offers an incremental prognostic value for patients with dilated cardiomyopathy

Abstract

AIMS: Right ventricular (RV) as well as left ventricular (LV) function has been recognized as an important prognostic factor for heart failure patients. Our objective was thus to investigate the prognostic significance of combined assessment of bi-ventricular functional reserve for patients with dilated cardiomyopathy (DCM). METHODS AND RESULTS: We studied 104 DCM patients with ejection fractions (EF) of 32 ± 9%, and speckle-tracking echocardiography was used to assess both RV and LV contractile reserve under dobutamine stress (20 µg/kg/min). RV contractile function was measured as peak global longitudinal strain (GLS) from the RV free wall (RV-free), and LV function as global circumferential strain (GCS) and GLS, respectively. Event-free survival was then tracked for 17 months. Twenty-one patients (20%) developed cardiovascular events. A multivariate Cox proportional-hazards analysis revealed that the baseline EF, E/A, and the relative change in EF (ΔEF), in GCS (ΔGCS), and in RV-free (ΔRV-free) during dobutamine stress were the independent predictors of cardiovascular events (P < 0.001, <0.05, <0.01, <0.05, and <0.01, respectively). A Cox model based on baseline clinical and echocardiographic variables (χ(2) = 23.6) was improved by the addition of LV contractile reserve parameters (plus ΔGCS and ΔEF) (χ(2) = 49.1; P < 0.001) and further improved by adding RV contractile reserve (plus ΔRV-free) (χ(2) = 60.3, P < 0.001). CONCLUSION: Assessment of RV contractile reserve during dobutamine stress offers a significantly better prognostic value for patients with DCM. Bi-ventricular contractile reserve may be required for a favourable outcome, so that estimation of RV contractile reserve should be considered part of a comprehensive functional assessment of these patients.