In an adult canine model of gradual pressure overload, baseline mean systolic wall stress >115 kdyne/cm2 predicted the development of left ventricular dysfunction in 18 of 20 dogs.
BACKGROUND: When a pressure overload is placed on the left ventricle, some patients develop relatively modest hypertrophy whereas others develop extensive hypertrophy. Likewise, the occurrence of contractile dysfunction also is variable. The cause of this heterogeneity is not well understood. METHODS AND RESULTS: We recently developed a model of gradual proximal aortic constriction in the adult canine that mimicked the heterogeneity of the hypertrophic response seen in humans. We hypothesized that differences in outcome were related to differences present before banding. Fifteen animals were studied initially. Ten developed left ventricular dysfunction (dys group). Five dogs maintained normal function (nl group). At baseline, the nl group had a lower mean systolic wall stress (96 +/- 9 kdyne/cm2; dys group, 156 +/- 7 kdyne/cm2; P 115 kdyne/cm2 developed dysfunction whereas 6 of 8 dogs with resting stress < or = 115 kdyne/cm2 maintained normal function. CONCLUSIONS: We conclude that this canine model mimicked the heterogeneous hypertrophic response seen in humans. In the group that eventually developed dysfunction there was less cardiac mass despite 60% higher wall stress at baseline, suggesting a different set point for regulating myocardial growth in the two groups.
Koide et al. (Tue,) conducted a other in Left ventricular dysfunction (n=43). Gradual proximal aortic constriction was evaluated on Development of left ventricular dysfunction. In an adult canine model of gradual pressure overload, baseline mean systolic wall stress >115 kdyne/cm2 predicted the development of left ventricular dysfunction in 18 of 20 dogs.