AJP - Heart and Circulatory Physiology, Vol 270, Issue 4 1279-H1286, Copyright © 1996 by American Physiological Society
Effect of dobutamine of ventriculoarterial coupling in acute regional myocardial ischemia in dogs
H. Seki, K. Katayama, H. Sakai, T. Yonezawa, H. Kunichika, Y. Saeki, T. Hiro and M. Matsuzaki
Second Department of Internal Medicine, Yamaguchi University School of Medicine, Japan.
We assessed the effect of dobutamine on left ventricoarterial coupling
during acute regional ischemia. Using a conductance catheter, we analyzed
the end-systolic pressure-volume relation (ESPVR) in anesthetized dogs. We
calculated the slope of ESPVR (Ees), the slope of the end-systolic
pressure-stroke volume relation (Ea), (Ea/Ees) and the ratio (work
efficiency) of external work to pressure-volume area at base-line during
ischemia induced by occlusion of the left anterior descending coronary
artery and during low-dose (1-3 micrograms.min-1.kg-1) and high-dose (4-10
micrograms.min-1.kg-1)dobutamine infusions with ischemia. ESPVR shifted to
the right without a change in Ees during ischemia. Dobutamine caused
dose-dependent increases in Ees but did not affect the intercept of ESPVR.
During ischemia, Ea/Ees increased and work efficiency decreased. Low-dose
dobutamine was associated with a return in control for Ea/Ees and work
efficiency. High-dose dobutamine increased Ees and Ea but produced no
further increase in Ea/Ees or work efficiency. Low-dose dobutamine would
appear to be the preferable regimen to achieve the optimal
ventriculoarterial coupling in acute regional ischemia associated with
mismatched ventriculoarterial coupling and depressed left ventricular work
efficiency.
