AJP - Heart and Circulatory Physiology, Vol 257, Issue 1 113-H119, Copyright © 1989 by American Physiological Society

ARTICLES

Characteristics of regional myocardial stunning after exercise in dogs with chronic coronary stenosis

E. Thaulow, B. D. Guth, G. Heusch, E. Gilpin, R. Schulz, K. Kroeger and J. Ross Jr
Seaweed Canyon Laboratory, Department of Medicine, University of California, San Diego, La Jolla 92093.

Persistent impairment of regional contraction of the left ventricle after restoration of blood flow following transient coronary occlusion has been termed "stunning," and reversible regional dysfunction has also been observed during recovery from exercise-induced regional ischemia. To determine whether limitation of subendocardial blood flow after exercise is a determinant of such dysfunction in the presence of chronic coronary stenosis, nine conscious chronically instrumented dogs having an Ameroid constrictor were studied before, during, and after treadmill runs that induced regional ischemia. During exercise, systolic wall thickening (%WTh, sonomicrometers) in the ischemic region decreased from a normal level of 22.1 +/- 9.1% at rest to 8.8 +/- 5.2% (+/- SD, P less than 0.01), whereas subendocardial blood flow (microspheres) in the ischemic region decreased from 0.75 +/- 0.25 to 0.45 +/- 0.27 ml.min-1.g-1 (P less than 0.05). %WTh in the ischemic region gradually improved after exercise but remained depressed (75% of control) at 30 min after the run (P less than 0.05). Postexercise dysfunction was not related to simultaneous regional hypoperfusion, since at 5 and 10 min after running there was a tendency toward subendocardial hyperemia (control 0.75 vs. 1.33 and 1.30 ml.min-1.g-1, NS) with a return to control by 30 min. Thus persistent regional dysfunction after exercise-induced regional ischemia in the conscious dog is not due to sustained subendocardial ischemia in the presence of chronic coronary stenosis and represents an example of myocardial stunning.

This article has been cited by other articles:

				P. G. Camici and D. P. Dutka Repetitive stunning, hibernation, and heart failure: contribution of PET to establishing a link Am J Physiol Heart Circ Physiol, March 1, 2001; 280(3): H929 - H936. [Full Text] [PDF]

				O. Parent De Curzon, B. Ghaleh, R. Tissier, J.-F. Giudicelli, L. Hittinger, and A. Berdeaux Myocardial stunning in exercise-induced ischemia in dogs: lack of late preconditioning Am J Physiol Heart Circ Physiol, January 1, 2001; 280(1): H302 - H310. [Abstract] [Full Text] [PDF]

				G. Ambrosio, S. Betocchi, L. Pace, M. A. Losi, P. Perrone-Filardi, A. Soricelli, F. Piscione, J. Taube, F. Squame, M. Salvatore, et al. Prolonged Impairment of Regional Contractile Function After Resolution of Exercise-Induced Angina: Evidence of Myocardial Stunning in Patients With Coronary Artery Disease Circulation, November 15, 1996; 94(10): 2455 - 2464. [Abstract] [Full Text]

				E. Barnes, D. P. Dutka, M. Khan, P. G. Camici, and R. J. Hall Effect of repeated episodes of reversible myocardial ischemia on myocardial blood flow and function in humans Am J Physiol Heart Circ Physiol, May 1, 2002; 282(5): H1603 - H1608. [Abstract] [Full Text] [PDF]