Pressure-Volume Relationship During Dobutamine Stress Echocardiography Predicts Exercise Tolerance in Patients with Congestive Heart Failure

Abstract

The pressure-volume relationship (PVR) is a useful method for evaluating left ventricular (LV) myocardial contractility during dobutamine stress echocardiography (DSE). The investigators assessed PVRs, systolic and diastolic function, B-type natriuretic peptide (BNP) levels, and aerobic exercise capacity in patients with congestive heart failure (CHF). A total of 84 patients with CHF (mean age, 68 +/- 9 years) underwent high-dose DSE. PVR was defined as the systolic cuff pressure/end-systolic volume index difference between rest and peak DSE. Of these, 67 patients also underwent cardiopulmonary exercise testing. The patients were divided into 3 equal groups on the basis of PVR: lower, intermediate, and higher. PVRs were significantly lower in more symptomatic patients (New York Heart Association class II vs III) (2.17 +/- 1.99 vs 0.91 +/- 0.72 mm Hg/mL/m(2), P < .001). Patients with elevated LV filling pressures (E/Ea >or= 14) showed significantly lower PVRs compared with patients with normal or slightly abnormal LV filling pressures (1.1 +/- 1.1 vs 2.96 +/- 3.11 mm Hg/mL/m(2), P = .006). Patients with higher PVRs showed lower logarithmically transformed BNP levels (2.0 +/- 0.5, 2.5 +/- 0.3, and 2.6 +/- 0.5 pg/mL; P < .001), higher peak oxygen consumption (17 +/- 4, 13 +/- 3, and 12 +/- 3 mL/kg/min; P < .001), and higher rest-stress percentage changes in ejection fraction (80 +/- 50%, 56 +/- 29%, and 22 +/- 32%; P < .001) compared with patients with intermediate and lower PVRs, respectively. The parameters predictive of exercise tolerance were PVR (odds ratio [OR]; 1.582, 95% confidence interval [CI], 1.136-2.204; P = .007), ejection fraction (OR, 1.172; 95% CI, 1.070-1.283; P = .001), log BNP (OR, 0.080; 95% CI, 0.020-0.325; P < .001), and E/Ea (OR, 0.836; 95% CI, 0.733-0.953; P = .007). In patients with CHF, impaired noninvasively assessed myocardial contractility is related to impaired systolic and diastolic function, higher BNP levels, and poorer exercise tolerance.