Pressure-Volume Relationship During Dobutamine Stress Echocardiography Predicts Exercise Tolerance in Patients with Congestive Heart Failure
published online 04 December 2009.
Background
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).
Methods
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.
Results
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/m2, P < .001). Patients with elevated LV filling pressures (E/Ea ≥ 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/m2, 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).
Conclusions
In patients with CHF, impaired noninvasively assessed myocardial contractility is related to impaired systolic and diastolic function, higher BNP levels, and poorer exercise tolerance.
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