Haemodynamic profile of acebutolol in acute myocardial infarction

This paper evaluates the haemodynamics of intravenous Acebutolol (SECTRAL) (0.5 mgm/Kgm) in the acute phase of myocardial infarction uncomplicated by hypertension, cardiac failure or conduction abnormalities. Nineteen observations were made on 15 consecutive patients. Haemodynamic parameters were recorded just before, and at 15 and 30 min after injections, using Swan-Ganz Catheter-Thermister and Edslab Cardiac Output Computer (9520) in the Intensive Care Unit. All patients survived; none had extension of infarction. The Heart Rate dropped by 9 +/- 1% (+/- SEM) (from 90.2 +/- 4.0 to 81.6 +/- 3.1 per min, P less than 0.001) but systolic and mean Blood Pressures were not significantly altered. Pulmonary Capillary Pressure was elevated by 2.5 +/- 6% (from 11.6 +/- 0.8 to 14.4 +/- 0.9 mmHg P less than 0.001) but cardiac failure hardly ever developed clinically. The mean Pulmonary Arterial Pressure rose by 10 +/- 2% (P less than 0.005) while the Right Atrial mean increased from 6.0 +/- 1.0 to 8.3 +/- 1.3 mm Hg (P less than 0.005). Although the Cardiac Index was depressed by 11 +/- 2% (from 3.0 +/- 0.1 to 2.7 +/- 0.1 L/min/M2; P less than 0.001), the Stroke Index remained virtually unaffected. Myocardial oxygen consumption per min as reflected by Heart Rate x BP product declined by 12 +/- 2% (P less than 0.001), while the Stroke Work Index was lowered by 9 +/- 3% (P less than 0.005). The haemodynamic profile indicates that intravenous Acebutolol in uncomplicated infarcts is well tolerated, and that it could be employed with advantage to manipulate determinants of myocardial oxygen consumption through reduction of Heart Rate Pressure product and Stroke Work Index.