RIGHT VENTRICULAR FUNCTION COUPLING TO THE PULMONARY CIRCULATION PREDICTS EXERCISE TOLERANCE IN PATIENTS WITH HEART FAILURE AND REDUCED EJECTION FRACTION: INSIGHT FROM THE EVALUATION OF RESYNCHRONIZATION THERAPY FOR HEART FAILURE (EARTH) TRIAL

Purpose Exercise tolerance has important prognostic value in patients with heart failure and reduced ejection fraction (HFrEF). The relationship between right ventricular function and its coupling to pulmonary circulation (RV-PA) and cardiopulmonary exercise tests (CPET) is not fully understood. We aimed to evaluate the value of RV echocardiographic parameters, including RV-PA, to predict exercise tolerance in HFrEF patients. Methods We performed a sub-analysis of EARTH, which enrolled HFrEF patients undergoing defibrillator implantation. At baseline, an echocardiogram and various CPET [peak VO2; minute ventilation/carbon dioxide production slope (VE/VCO2); 6-minute walk distance (6MWD) and submaximal exercise duration (SED)] were performed. The primary outcome was the correlation of RV-PA (using TAPSE/sPAP, tricuspid annular plane systolic excursion on pulmonary artery systolic pressure ratio (T/P)) with peak VO2. Secondary outcomes include correlation between various RV parameters such as size [diameter at inlet and end-diastolic area in apical 4-chamber], RV function [TAPSE; right ventricular fractional area change (RV-FAC); RV myocardial performance index (RV-MPI)], sPAP and tricuspid regurgitation grade (TRG); and CPET variables. Univariate and multivariate linear regression models were used on patients for which both TAPSE and sPAP were available. Results 205 patients were enrolled in EARTH, with 100 having data on both TAPSE and sPAP (Men: 70.0%; NYHA class II: 55.0%; mean LVEF 26.5±7.8%). T/P was the only parameter found to be predictive of peak VO2 (β=6.8, p Conclusion In HFrEF patients, RV-PA coupling (using TAPSE/sPAP) is a powerful predictor of maximal and submaximal exercise capacity and has a greater predictive value than the usual parameters including age, sex and LVEF.