AJP - Heart and Circulatory Physiology, Vol 251, Issue 5 949-H956, Copyright © 1986 by American Physiological Society
Myocardial blood flow in left ventricular hypertrophy developing in young and adult dogs
R. J. Bache, D. Alyono, E. Sublett and X. Z. Dai
This study was performed to test the hypothesis that growth of coronary
vasculature would be facilitated if myocardial hypertrophy occurred during
the period of normal body growth rather than in mature adult animals. Left
ventricular hypertrophy was produced by banding the ascending aorta in
eight young dogs 7 wk of age and in nine adult dogs. Adult dogs were
studied 2 mo after aortic banding, whereas young dogs were allowed to grow
to adulthood before study. Left ventricular weight-to-body weight ratios
were increased to 6.88 +/- 0.36 g/kg in the young dogs and 6.64 +/- 0.47 in
adult dogs; both were significantly greater than seven normal control
animals (4.32 +/- 0.05; each P less than 0.01). Myocardial blood flow per
gram measured with microspheres during quiet resting conditions was
significantly higher in young dogs with left ventricular hypertrophy than
in normal dogs. Myocardial blood flow rates during maximum coronary
vasodilation with adenosine (4 mumol X kg-1 X min-1 iv) were similar in all
three groups. However, since mean coronary perfusion pressure was higher in
the dogs with aortic banding, minimum coronary vascular resistance per gram
of myocardium was significantly higher in both young (21.1 +/- 3.1 mmHg X
ml-1 X min X g) and adult dogs with left ventricular hypertrophy (21.8 +/-
2.2) than in the normal dogs (16.8 +/- 3.1; each P less than 0.01). Mean
coronary vascular resistance for the total left ventricle was similar in
all three groups of animals, suggesting that growth of coronary vasculature
did not occur as the myocardium underwent hypertrophy.(ABSTRACT TRUNCATED
AT 250 WORDS)
