title: Effect of amrinone on right ventricular function: predominance of afterload reduction.
abstract: Although the bipyridine agent amrinone is reported to have a positive inotropic effect on the left ventricle, the effect of this drug on right ventricular contractility in the clinical setting is unknown. We studied the effect of short-term intravenous administration of amrinone on right ventricular systolic function in nine patients with severe congestive heart failure and, using radionuclide ventriculography, examined the right ventricular end-systolic pressure-volume relationship to determine whether reduced right ventricular afterload or increased contractility predominantly accounted for the observed improvement in right ventricular systolic function. In each patient the right ventricular end-systolic pressure-volume relationship was derived with use of varying doses of nitroprusside. After nitroprusside was stopped, intravenous amrinone (3 mg/kg) caused decreases from baseline in pulmonary arterial end-systolic pressure in eight of nine patients (23 +/- 11% [overall mean +/- SE], p less than .05), and in pulmonary vascular resistance in all patients (38 +/- 6%, p less than .001). Right ventricular end-systolic volume decreased (23 +/- 8%, p less than .01) and right ventricular ejection fraction increased (31 +/- 10%, p = .01). The amrinone-induced decrease in right ventricular end-systolic volume was compared with that predicted for right ventricular afterload reduction alone based on the effect of amrinone on pulmonary arterial end-systolic pressure and the pressure-volume relationship observed during infusion of nitroprusside.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000328:Adult; D000368:Aged; D000631:Aminopyridines / Q000494:pharmacology / Q000627:therapeutic use*; D000676:Amrinone; D001794:Blood Pressure / Q000187:drug effects; D005260:Female; D006333:Heart Failure / Q000188:drug therapy*; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000187:drug effects; D009599:Nitroprusside / Q000627:therapeutic use; D013318:Stroke Volume / Q000187:drug effects; D014655:Vascular Resistance / Q000187:drug effects
chemical_list: D000631:Aminopyridines; D009599:Nitroprusside; D000676:Amrinone