HEMODYNAMIC EFFECTS OF PROPRANOLOL (INDERAL®) AND H 56/28 (APTIN®) IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION

Abstract

Abstract The hemodynamic effects of propranolol (Inderal®) and H 56/28 (Aptin®) were compared in a study of 17 patients in the acute stage of myocardial infarction. Eight patients received 5 mg propranolol i. v. (group I) and the remainder 5 mg H 56/28 (group A). Cardiac index (CI), heart rate (HR) and stroke index (SI) were significantly reduced after both drugs. The difference between mean CI and SI reductions in the two groups was not significant ( p > 0.05), while the difference between mean HR reductions was almost significant (0.02 < p > 0.05). Total peripheral resistance index (TPRI), circulation time (CT) and right atrial mean blood pressure (RAMP) increased significantly in both groups. The difference between mean TPRI, CT and RAMP increases in the two groups was not significant for TPRI ( p > 0.05) but almost significant for CT and RAMP (0.01 > p < 0.05). Arterial systolic blood pressure (SBP) fell almost significantly (0.02 < p < 0.05) in group I, while no change occurred in group A. Arterial diastolic and mean blood pressures did not change in either group. It is concluded that propranolol and H 56/28 have about equal effects on most of the measured parameters in patients with strong sympathetic drive. The intrinsic sympathetic stimulating action of H 5628 is not sufficient to compensate for the β ‐adrenergic receptor blocking effect of the drug in this situation. The two drugs should therefore both be considered dangerous in patients in whom augmented sympathetic drive is necessary for the maintenance of adequate cardiac contractility and rate. The tendency to bradycardia, prolonged circulation time and hypotension may be slightly less after H 56/28 than after propranolol injected intravenously in the same doses.