Haemodynamic effects of intravenously administered prenalterol in patients with severe heart failure

The acute haemodynamic effects of prenalterol 75-225 micrograms/kg i.v. were studied at rest and during exercise in the supine position in 12 patients with chronic congestive heart failure secondary to myocardial infarction (6 pts), chronic valvular disease with valvular replacement (4 pts), ischaemic cardiomyopathy (1 pt) and post myocarditis (1 pt). In 5 of the 6 AMI patients the effect of prenalterol on myocardial oxygen consumption at rest was measured. Pulmonary artery end-diastolic pressure decreased significantly from 17 to 10 mm Hg at rest and from 31 to 21 mm Hg during exercise. Resting heart rate increased from 78 to 90 at rest but was unchanged during exercise. MVO2 in the 5 patients was unchanged or lower in 4 patients and increased in one in whom angina developed after prenalterol. In general, dyspnoea and angina during exercise were less pronounced after prenalterol. The calculated triple product was lower after prenalterol, especially during exercise, indicating lower myocardial oxygen consumption and probably less myocardial ischaemia.