BENEFICIAL CUMULATIVE ROLE OF BOTH NITROGLYCERIN AND DOBUTAMINE ON RIGHT-VENTRICULAR SYSTOLIC FUNCTION IN CONGESTIVE-HEART-FAILURE PATIENTSAWAITING HEART-TRANSPLANTATION

End-stage idiopathic dilated cardiomyopathy or ischemic heart disease usually present with very low cardiac output and severe ventricular dy sfunction which may require pharmacological support before heart trans plantation. 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 hemodyn amic parameters to nitroglycerin and dobutamine usually used to treat severe left ventricular dysfunction, we studied 17 congestive heart fa ilure 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 techniqu e using a dedicated catheter with a fast catheter-computer response, p ermitting instantaneous measurements of right ventricular ejection fra ction, was used. Right ventricular hemodynamic parameters were recorde d at baseline, after an intravenous bolus injection of 3 mg nitroglyce rin and after an intravenous infusion of dobutamine administered after nitroglycerin until normalization of cardiac index or a maximal dose of 15 mu g/kg/min. Pulmonary artery mean pressure significantly decrea sed 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 n ot affected by nitroglycerin (1.7 +/- 0.4 l/min/m(2) at baseline vs. 2 .0 +/- 0.3 l/min/m(2) after nitroglycerin, ns), but dramatically incre ased after dobutamine (3.0 +/- 1.0 l/min/m(2) after dobutamine, P < 0. 0001). Concomitantly to the changes of these two parameters, right ven tricular ejection fraction progressively increased (14 +/- 8% at basel ine vs. 20 +/- 10% after nitroglycerin (P < 0.0006) vs. 28 +/- 13% aft er dobutamine (P < 0.0001)), Progressive increase of right ventricular ejection fraction after administration of nitroglycerin followed by a dministration of dobutamine suggests the beneficial cumulative role of both medications on right ventricular systolic function in severe con gestive heart failure.