The acute hemodynamic response to pirbuterol at rest and exercise in patients with heart failure with observations on long-term response.

Rest and exercise hemodynamics with the beta agonist pirbuterol and a placebo preparation were studied in seven patients with severe chronic congestive heart failure. At rest, pirbuterol increased cardiac index (1.8 +/- 0.3 to 2.3 +/- 0.4 L/min/M2, p less than 0.01) and decreased systemic vascular resistance (1899 +/- 405 to 1419 +/- 257 dynes-sec-cm-5, p less than 0.01) without a significant change in heart rate, right atrial, pulmonary arterial, pulmonary arterial wedge, or systemic arterial pressures. Although there were slight increases in cardiac index at peak exercise with pirbuterol, neither total exercise time nor peak oxygen consumption were improved with this agent. No significant hemodynamic changes occurred with placebo at rest, nor was there improvement in exercise performance following placebo. Of three patients studied at six weeks, two showed total loss of hemodynamic effect of pirbuterol compared to the acute response. In conclusion, although acute rest hemodynamics improve with pirbuterol, the lack of improved acute exercise performance and the decrease in hemodynamic responsivity at six weeks appear to limit its usefulness in the treatment of heart failure.