Changes in ischemic blood flow distribution and dynamic severity of a coronary stenosis induced by beta blockade in the canine heart. Circulation 1981 Oct;64(4):708-15
Date
10/01/1981Pubmed ID
6115724DOI
10.1161/01.cir.64.4.708Scopus ID
2-s2.0-0019520743 (requires institutional sign-in at Scopus site) 51 CitationsAbstract
The effects of equipotent beta 1-receptor-blocking doses of propranolol, metoprolol and sotalol on distal coronary pressure, stenosis resistance and regional myocardial blood flow (endo/epi) were studied in anesthetized dogs with a severe noncircumferential stenosis of the left circumflex coronary artery. No significant differences between the three beta blockers were observed for overall hemodynamics and regional myocardial blood flow. After drug treatment, subendocardial blood flow (0.47 +/- 0.05 to 0.78 +/- 0.05 ml/min/g) and endo/epi (0.67 +/-0.04 to 1.18 +/- 0.04) increased significantly (p less than 0.05) in the ischemic region. These changes were associated with a marked increase in distal coronary perfusion pressure and a decrease in heart rate. Resistance across the stenosis decreased significantly (p less than 0.05) after beta-receptor blockade (3.2 +/- 0.3 to 1.4 +/- 0.2 units). Atrial pacing to control heart rate only partially attenuated these changes. These results suggest that a favorable redistribution of ischemic blood flow after beta blockade is the result of an increase in distal diastolic pressure-time index and an autoregulation-induced increase in distal bed vascular resistance due to a decrease in myocardial oxygen demand associated with beta blockade. The latter effect also resulted in a decrease in the dynamic severity of a proximal coronary stenosis.
Author List
Buck JD, Hardman HF, Warltier DC, Gross GJMESH terms used to index this publication - Major topics in bold
Adrenergic beta-AntagonistsAnimals
Blood Pressure
Constriction, Pathologic
Coronary Circulation
Coronary Disease
Dogs
Female
Hemodynamics
Male
Metoprolol
Propranolol
Sotalol
Vascular Resistance
