Open AccessPropranolol during the evolution and subsequent ten days of myocardial infarction in man: Hemodynamic, initial cardiac energetic, and neurohumoral responses
Author(s) -
Mueller I. S.,
Rao P. S.,
Fletcher J.,
Evans R.,
Hertelendy F.,
Stickley L.,
Walter K.
Publication year - 1979
Publication title -
clinical cardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.263
H-Index - 72
eISSN - 1932-8737
pISSN - 0160-9289
DOI - 10.1002/clc.4960020602
Subject(s) - propranolol , medicine , epinephrine , myocardial infarction , endocrinology , hemodynamics , pulmonary wedge pressure , insulin , ejection fraction , cardiac output , cardiology , glucagon , heart failure , anesthesia
Abstract During the evolution of transmural myocardial infarction an intensive sympathetic hyperactivity was observed. Plasma l ‐norepinephrine and epinephrine contents were strikingly increased, the mean values to 2.047±1.10 (SD) and 0.947±0.48 μg/l, respectively. Propranolol (0.1 mg/kg) was administered intravenously within an average of 8.8 h of transmural myocardial infarction to 55 patients who did not show significant left ventricular failure. The drug was continued orally with an average dose of 567±20 (SD) mg q6h for 10 d. Mean plasma propranolol levels during the first 5 d ranged between 89 and 162 ng/ml. Cardiac index, left ventricular ejection fraction, and, to a lesser degree, blood pressure significantly decreased. Mean pulmonary capillary wedge pressure remained unchanged. Decreases in coronary blood flow and myocardial oxygen consumption were associated with improvement of myocardial lactate metabolism, suggesting reduced myocardial oxygen requirements. Plasma free fatty acid contents significantly decreased. Myocardial glucose extraction and respiratory quotient increased, indicating enhanced carbohydrate utilization. Prior to propranolol administration, plasma glucose and glucagon contents were increased and plasma insulin levels were inappropriately low. Initial glucagon and initial l ‐norepinephrine and epinephrine contents were correlated (r = 0.54 and 0.50, p <0.01). Beta‐adrenergic blockade decreased plasma insulin contents in spite of hyperglycemia and abolished the correlation between glucagon and catecholamines. Propranolol was tolerated well by all patients; none of them developed acute left ventricular failure. The study demonstrates that propranolol can be safely administered during the evolution and early phase of transmural myocardial infarction, if selection criteria for patients are carefully considered. Propranolol, dampening the response to acute ischemic stress, diminishes energy requirements and thus appears to be a promising drug for preservation of ischemic myocardium.