EFFECTS OF DOBUTAMINE AND ENOXIMONE ON TRANSMITRAL AND PULMONARY VENOUS FLOW CHARACTERISTICS IN PATIENTS WITH LEFT-VENTRICULAR DYSFUNCTION AFTER CORONARY-ARTERY BYPASS-GRAFTING

Objectives: To assess the effects of dobutamine and enoximone on trans mitral (TMF) and pulmonary venous flow (PVF) characteristics. Design: Prospective and randomized. Setting: A university hospital intensive c are unit. Participants: Thirty patients with moderate left ventricular dysfunction after coronary artery bypass grafting (CABG). Interventio ns: Patients received either dobutamine, 10 mu g/kg/min, or enoximone, 20 mu g/kg/min, for the treatment of a low cardiac index (CI) (<2.2 L /min/m(2)). Measurements and Main Results: Both drugs significantly (p < 0.05) increased CI from 1.91 +/- 0.17 (dobutamine) and 1.97 +/- 0.1 7 (enoximone) at baseline to 2.86 +/- 0.70 and 2.84 +/- 0.39 L/min/m(2 ), respectively. Compared with the enoximone (enox)-treated group, the administration of dobutamine (dob) resulted in significantly (p < 0.0 5) greater increases in mean arterial pressure (dob: 18 +/- 9% v enox: -2 +/- 7%), heart rate (dob: 24 +/- 13% v enox: 3 +/- 5%) and pulmona ry artery pressure (dob: 5 +/- 10% v enox: -4 +/- 9%). In contrast, th e increase in stroke volume index was significantly less in the dobuta mine-treated group (dob: 22 +/- 27% v enox: 41 +/- 21%). The TMF indic es, peak E, and peak A wave increased significantly (p < 0.05) after b oth dobutamine (baseline: 37.3 +/- 6.7 and 41.1 +/- 9.3; max dose: 42. 4 +/- 4.3 and 49.0 +/- 10.2 cm/s) and enoximone (baseline: 36.2 +/- 7. 5 and 44.2 +/- 10.9; max dose: 40.5 +/- 5.0 and 49.4 +/- 12.1 cm/s) wi thout significantly altering the E/A ratio. Only dobutamine significan tly (p < 0.05) decreased isovolumic relaxation time from 109 +/- 24 to 94 +/- 21 ms. There was no significant change in isovolumic relaxatio n time between the dobutamine (-12% +/- 17%)- and the enoximone (-4% /- 21%)-treated group. PVF recordings demonstrated a significant incre ase in time velocity integrals of the S wave with both dobutamine (12. 2 +/- 3.1 v 13.7 +/- 3.2 cm) and enoximone (11.0 +/- 3.0 v 12.2 +/- 3. 2 cm). No changes in the systolic fraction of the PVF were noted. Conc lusions: There were no major differences in parameters reflecting dias tolic function between the dobutamine and the enoximone-treated groups . Copyright (C) 1996 by W.B. Saunders Company