Maximal dyspnea on exertion during cardiopulmonary exercise testing is related to poor prognosis and echocardiography with tissue Doppler imaging in heart failure

This study tested the hypothesis that increasing levels of maximal dyspnea on exertion (DOE) during cardiopulmonary exercise testing (CPX) is associated with heart failure (HF) disease severity and worsening prognosis. Three hundred seventy-six HF patients underwent CPX where ventilatory efficiency (minute ventilation/carbon dioxide production; VE/VCO2 slope), peak oxygen consumption (VO2), and maximal DOE were determined. A subgroup of 243 patients underwent echocardiography with tissue Doppler imaging to measure the ratio between mitral early (E) to mitral annular (E′) velocity as well as other variables. Maximal DOE was significantly correlated with E/E′ (rs=.49; P<.001). In the multivariate Cox regression, the VE/VCO2 slope was the strongest prognostic marker obtained from CPX (Multivariate chi-square, 48.0; P<.001) while maximal DOE (residual chi-square, 17.4; P<.001) and peak VO2 (residual chi-square, 7.5; P=.006) added predictive value. These results suggest that increasing DOE reflects the degree of disease severity and adds prognostic value to established CPX variables.