The Journal of Thoracic and Cardiovascular Surgery, Vol 73, 431-435, Copyright © 1977 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
The effects of isoproterenol and dopamine on regional myocardial blood flow after stenosis of circumflex coronary artery
JH McClenathan, RA Guyton, RH Breyer, GE Newman and LL Michaelis
The effects of isoproterenol and dopamine on regional myocardial blood flow
were studied in 10 open-chest dogs after acute stenosis of the proximal
circumflex coronary artery. Blood flow was determined by the radioactive
microsphere technique. Isoproterenol led to a homogenous increase in blood
flow in the normal myocardium. In the myocardium with compromised coronary
blood flow, isoproterenol led to a relative subendocardial ischemia. This
occurred despite increased aortic flow and peak left ventricular dp/dt.
Dopamine also increased aortic flow and peak left ventricular dp/dt, but it
did not cause regional myocardial ischemia. The findings suggest that
dopamine is the preferable inotropic agent in managing low cardiac output
in patients with significant coronary artery disease.