Right ventricular failure after heart transplantation has been well documented as a major determinant of patient outcome. In 50 patients undergoing orthotopic heart transplantation, nine male patients with an average age of 41 years had in the immediate postoperative period a syndrome that consisted of low cardiac index, high right atrial and pulmonary artery pressures, and high pulmonary vascular resistance. The preoperative data showed: right atrial pressure, 9 +/- 6 mm Hg; pulmonary pressure, 38 +/- 10 mm Hg; cardiac index, 1.6 +/- 0.4 L/min/m2; pulmonary vascular resistance, 466 +/- 91 dynes/sec/cm-5; pulmonary wedge pressure, 15 +/- 6 mm Hg; and systemic vascular resistance, 2089 +/- 290 dynes/sec/cm-5. The immediate postoperative data revealed: right atrial pressure, 17 +/- 5; pulmonary artery pressure, 32 +/- 8; cardiac index, 2.2 +/- 0.7; pulmonary vascular resistance, 421 +/- 368; pulmonary wedge pressure, 15 +/- 6; systemic vascular resistance 1318 +/- 263. All of these patients were receiving inotropic and vasodilator drugs with no improvement after volume challenge. Prostacyclin was started, and the dose increased from 0.5 to 5.0 ng/kg/min, until an increase in cardiac index and a reduction in pulmonary resistance were achieved. The final profile was right atrial pressure, 12 +/- 5; pulmonary artery pressure, 24 +/- 6; cardiac index, 3.7 +/- 1.2; pulmonary vascular resistance, 122 +/- 42; pulmonary wedge pressure, 14 +/- 4; systemic vascular resistance, 870 +/- 263. The use of prostacyclin enabled the weaning of other drugs within a 48-hour period with no side effects and no worsening of the hemodynamic conditions after discontinuation of prostacyclin.