Relationship between echocardiographic and functional parameters in patients with heart failure undergoing cardiopulmonary exercise test.

BACKGROUND: HF patients typically show effort intolerance due to a reduction in peak exercise oxygen (peak VO2) consumption, which is related to inability to adapt systolic function to increased demand. Left ventricular ejection fraction (EF) is a surrogate marker of cardiac contractility and a powerful predictor of adverse prognosis in chronic heart failure (HF). The aim of the study was to explore the relationship between EF and other echocardiographic findings with peak VO2 in a population of HF individuals undergoing cardiopulmonary exercise testing (CPX). METHODS: We evaluated 101 patients (61% hypertensives, 74% with documented coronary artery disease) undergoing both resting echocardiography and symptom-limited CPX. RESULTS: Mean age was 58±13 years, 83% were males. Mean EF was 55±12%; 20% of the patients showed EF<40%. Mean test duration was 9.4±2.2 min. Average peak VO2 was 21±6 mL/kg/min. Peak VO2 showed a robust positive correlation with EF (R=0.42, P<0.001). Other independent predictors of peak VO2 were age, male sex, height and tricuspidal anular plane systolic excursion (TAPSE), this latter reflecting right ventricular dysfunction. When subjects were dichotomized according to predicted peak VO2values, those with higher-than-predicted peak VO2 showed significantly lower VE/VCO2 slope, and higher values of both oxygen pulse and VO2/WR slope. CONCLUSIONS: EF and TAPSE are associated with peak VO2 in HF patients independently from age, sex and height. The evaluation of potentially relevant mechanisms affecting exercise capacity in HF patients requires further investigation.