AJP - Heart and Circulatory Physiology, Vol 240, Issue 2 293-H299, Copyright © 1981 by American Physiological Society
Regional left ventricular wall thickness early and late after coronary occlusion in the conscious dog
S. Sasayama, K. P. Gallagher, W. S. Kemper, D. Franklin and J. Ross Jr
Regional wall thickness and endocardial segment lengths in normal and
ischemic zones of the left ventricle were measured simultaneously with
ultrasonic-dimension gauges before and after chronic circumflex artery
occlusion in conscious dogs. After 3 wk, end-diastolic segment lengths
(EDL) in normal zones increase 10% (P less than 0.01), shortening increased
22% (P less than 0.05), and end-diastolic wall thickness (EDWT) was reduced
by 12.8% (P less than 0.01). In ischemic zones at 3 wk, EDL was reduced by
15.4% (P less than 0.01), and subendocardial shortening recovered slightly
to 15% of control; EDWT increased 11% at 3 days postocclusion and
thereafter remained near control values (change not significant), but
systolic wall thickening improved substantially, reaching 38% of control at
3 wk. Thus, tissue loss and slight return of function occurred in the
ischemic subendocardium, whereas overall wall function (as reflected by
regional wall thickening) improved considerably over time. These findings
suggest that recovery of function in the outer layers of the wall after
myocardial infarction modifies the close correlation between regional
subendocardial segment and wall thickening dynamics observed acutely.
