Author + information
- Received June 19, 1984
- Revision received October 17, 1984
- Accepted November 6, 1984
- Published online April 1, 1985.
- Richard W. Smalling, MD, PhD, FACC*,1,2,
- Katharine Kelley, MS1,
- Richard L. Kirkeeide, PhD1 and
- David J. Fisher, MD, FACC1
- ↵*Address for reprints: Richard W. Smalling, MD, Assistant Professor of Medicine, University of Texas Medical School at Houston, Division of Cardiology, P.O. Box 20708, Houston, Texas 77225.
It has been suggested that vasodilation distal to a stenosis may cause a profound decrease in perfusion pressure and adversely affect regional left ventricular function. This phenomenon could explain the clinical concept of reversal of regional dysfunction by coronary revascularization. To evaluate the hypothesis that regional myocardial function parallels regional coronary blood pressure in the absence of changes in coronary flow, dogs chronically instrumented with left circumflex coronary artery flow probes, cuff occluders, pressure catheters and segmental function sonomicrometers were studied. By decreasing regional coronary vascular resistance with selective intracoronary dipyridamole and controlling blood flow with a proximal coronary cuff occluder, the mean left circumflex artery pressure was reduced from 83 ± 3 to 38 ± 2 mm Hg while circumflex coronary blood flow was maintained constant. Regional contractile function as measured by circumflex sonomicrometers was unchanged at constant circumflex subendocardial blood flow as measured by radioactive microspheres.
These findings suggest that regional contractile function is dependent on subendocardial blood flow and is independent of coronary perfusion pressure.
- Received June 19, 1984.
- Revision received October 17, 1984.
- Accepted November 6, 1984.
- American College of Cardiology Foundation