Beneficial cumulative role of both nitroglycerin and dobutamine on right ventricular systolic function in congestive heart failure patients awaiting heart transplantation.

End-stage idiopathic dilated cardiomyopathy or ischemic heart disease usually present with very low cardiac output and severe ventricular dysfunction which may require pharmacological support before heart transplantation. Right ventricular ejection fraction might be an important factor of functional capacity and survival in congestive heart failure. In order to test the immediate response of right ventricular hemodynamic parameters to nitroglycerin and dobutamine usually used to treat severe left ventricular dysfunction, we studied 17 congestive heart failure patients (15 men, two women; mean age 55 +/- 13 years) with end-stage idiopathic dilated cardiomyopathy (n = 10) or end-stage ischemic heart disease (n = 7), left ventricular ejection fraction < 35% (mean 22 +/- 8%), and sinus rhythm. A well validated thermodilution technique using a dedicated catheter with a fast catheter-computer response, permitting instantaneous measurements of right ventricular ejection fraction, was used. Right ventricular hemodynamic parameters were recorded at baseline, after an intravenous bolus injection of 3 mg nitroglycerin and after an intravenous infusion of dobutamine administered after nitroglycerin until normalization of cardiac index or a maximal dose of 15 micrograms/kg/min. Pulmonary artery mean pressure significantly decreased after nitroglycerin (43 +/- 9 mmHg at baseline vs. 31 +/- 10 mmHg after nitroglycerin, P < 0.0001) and did not subsequently change after dobutamine (32 +/- 10 mmHg after dobutamine, ns). Cardiac index was not affected by nitroglycerin (1.7 +/- 0. l/min/m2 at baseline vs. 2.0 +/- 0.3 l/min/m2 after nitroglycerin, ns), but dramatically increased after dobutamine (3.0 +/- 1.0 l/min/m2 after dobutamine, P < 0.0001). Concomitantly to the changes of these two parameters, right ventricular ejection fraction progressively increased (14 +/- 8% at baseline vs. 20 +/- 10% after nitroglycerin (P < 0.0006) vs. 28 +/- 13% after dobutamine (P < 0.0001)). Progressive increase of right ventricular ejection fraction after administration of nitroglycerin followed by administration of dobutamine suggests the beneficial cumulative role of both medications on right ventricular systolic function in severe congestive heart failure.