| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Departments of Medicine and Physiology, University of South Alabama, College of Medicine, Mobile, Alabama 36688
We evaluated the ability of ischemic
preconditioning to restore function to salvaged myocardium in rabbits.
Although ischemic preconditioning reduces infarct size, few
investigators studying recovery of function after coronary occlusions
lasting 
30 min have reported any mechanical benefit in preconditioned
hearts. However, because myocardial function was seldom evaluated
beyond 5 h after reperfusion stunning may have masked the benefit.
Accordingly, rabbits were chronically instrumented with a pneumatic
occluder around a branch of the left coronary artery, a pair of 1-mm
ultrasonic crystals in the myocardial territory destined to become
ischemic, and electrocardiogram (ECG) leads. One week after surgery the ECG and segment length tracing were recorded at rest, during 30-min occlusion and 1 h of reflow, and again at 24, 48, and 72 h. In ischemically preconditioned rabbits, 5-min coronary occlusion and
10-min reperfusion preceded the long occlusion. The beginning and end
of systole were determined by recording the first and second heart
sounds with a hand-held precordial microphone. Postmortem infarct size
was measured with triphenyltetrazolium chloride. During the 30-min
coronary occlusion all segments became nearly akinetic or bulged during
systole. After 60 min of reflow there was little return of function in
either group. Between 24 and 72 h there was minimal recovery in the
control group (segment shortening equals 13.3 ± 4.1% of baseline),
whereas function was much better in preconditioned hearts (44.2 ± 7.4% of baseline, P < 0.02).
Infarct size as a percentage of risk zone was much smaller in
preconditioned hearts (10.2 ± 1.4 vs. 29.7 ± 1.8%, P < 0.001). Thus there is a gradual
recovery of systolic function of reperfused myocardium after a coronary
occlusion. Although early mechanical recovery is significantly better
after preconditioning, it is much less than would be predicted by the
reduction of infarct size.
myocardial infarction; regional myocardial function; segment shortening; stunning
This article has been cited by other articles:
|
|
 |
|
  K. Aouam, R. Tissier, P. Bruneval, C. Mandet, A. Berdeaux, and B. Ghaleh Preconditioning of salvaged myocardium in conscious rabbits with postinfarction dysfunction Am J Physiol Heart Circ Physiol, June 1, 2005; 288(6): H2763 - H2769. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Coles Jr., D. C. Sigg, and P. A. Iaizzo Role of kappa -opioid receptor activation in pharmacological preconditioning of swine Am J Physiol Heart Circ Physiol, June 1, 2003; 284(6): H2091 - H2099. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Xi, D. Tekin, E. Gursoy, F. Salloum, J. E. Levasseur, and R. C. Kukreja Evidence that NOS2 acts as a trigger and mediator of late preconditioning induced by acute systemic hypoxia Am J Physiol Heart Circ Physiol, July 1, 2002; 283(1): H5 - H12. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. C. Sigg, J. A. Coles Jr., P. R. Oeltgen, and P. A. Iaizzo Role of delta -opioid receptor agonists on infarct size reduction in swine Am J Physiol Heart Circ Physiol, June 1, 2002; 282(6): H1953 - H1960. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Takano, X.-L. Tang, E. Kodani, and R. Bolli Late preconditioning enhances recovery of myocardial function after infarction in conscious rabbits Am J Physiol Heart Circ Physiol, November 1, 2000; 279(5): H2372 - H2381. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
