Superior Prognostic Value of Right Ventricular Free Wall Compared to Global Longitudinal Strain in Patients With Heart Failure

Abstract

Global right ventricular (RV) longitudinal strain (RVGLS) and free wall RV longitudinal strain (RVFWS) have both been advocated as sensitive tools to evaluate RV function and predict prognosis in patients with heart failure and reduced ejection fraction (HFrEF). However, because the interventricular septum is an integral part of the left ventricle (LV) also, RVGLS might be influenced by LV dysfunction. Thus, we compared the prognostic performance of either RV strain parameter in HFrEF patients, also taking into account the degree of LV systolic dysfunction. In 288 prospectively enrolled outpatients with stable HFrEF, RVGLS and RVFWS were assessed by speckle-tracking and LV systolic function by global longitudinal strain and LV ejection fraction. Patients were followed up for 30.2±23.0months; the primary endpoint was all-cause death/heart failure-related hospitalization. Prognostic performance was assessed by C-statistic and net reclassification improvement. There were 95 events during follow-up. By univariable analysis, both RVGLS (hazard ratio×1 SD, 1.60; 95% CI, 1.29-1.99; P<.0001) and RVFWS (hazard ratio×1 SD, 1.82; 95% CI, 1.45-2.29; P<.0001) were associated with outcome, and both remained significant after correction for EMPHASIS risk score, New York Heart Association class, natriuretic peptides, and therapy. However, after further correction for LV systolic function parameters, only RVFWS remained significantly associated with outcome (P<.01). A basic prediction model was improved by adding RVFWS (net reclassification improvement 0.390; P<.05), but not RVGLS. Although both RVGLS and RVFWS have prognostic value, RVFWS better predicts outcome in HFrEF patients, mainly because it is less influenced by LV longitudinal dysfunction.