ANTIISCHEMIC EFFECT OF GALLOPAMIL AND ESM OLOL IN INTRAINDIVIDUAL COMPARISON IN PATIENTS WITH CORONARY HEART-DISEASE

To compare the hemodynamic, antiischemic, metabolic, and neurohumoral effects of intravenous esmolol (beta1 blocking agent) and gallopamil ( verapamil-like calcium channel blocker), 14 patients with angiographic ally proven CAD and reproducible ST segment depression were studied at rest and during exercise under control conditions and after an intrav enous bolus injection of esmolol (0.5 mg/kg/1 min, followed by an infu sion with 0.2 mg/kg/min) or gallopamil (0.025 mg/kg/3 min). In contras t to gallopamil, esmolol significantly reduced systolic blood pressure (1 75.7 vs. 160 mm Hg) and heart rate (107.4 vs. 96.9 min-1) during e xercise as well as cardiac output (11.57 vs. 9.38 l/min) and significa ntly enhanced systemic vascular resistance both at rest (1241 vs. 1479 dynes . s . cm-5) and during exercise (805 vs. 947 dynes . s . cm-5). On the other hand, exercise filling pressures and lactate levels (3.6 6 vs. 3.05 mmol/l) were significantly reduced by gallopamil only. Thus , the significant improvement of exercise tolerance by both esmolol an d gallopamil is based on different mechanisms of action: esmolol impro ves myocardial ischemia by appreciably reducing myocardial oxygen cons umption, whereas gallopamil primarily improves oxygen supply and ventr icular performance. Plasma catecholamines, atrial natriuretic factor, and aldosterone levels as well as plasma renin activity were identical ly influenced by esmolol and gallopamil, respectively. A reflex activa tion of the sympathetic system did not occur.