Dissociation of pressure-rate product from myocardial oxygen consumption in dog.
Although the pressure-rate product (double product; DP) is generally recognized as a good index of myocardial oxygen consumption (VO2), catecholamines are reported to change the VO2-DP relationship. However, the separate influences of chronotropism and inotropism on the VO2-DP relation have not been studied. Therefore, we examined these influences in anesthetized open-chest dogs by cardiac pacing and dobutamine infusion. We observed two different VO2-DP lines under the separate chronotropic and inotropic changes. We interpreted such VO2-DP relations by the concept of the pressure-volume area (PVA). PVA is a measure of total mechanical energy for ventricular contraction and is a specific area in the ventricular pressure-volume (P-V) diagram circumscribed by the end-systolic and end-diastolic P-V relation curves and the systolic segment of the P-V trajectory. The empirical VO2-PVA relation that had been obtained in our previous studies reasonably simulated the dissociation of DP from VO2 under separate changes in chronotropism and inotropism.
Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka, Japan.
Y
Y
Yasumura
T
T
Nozawa
S
S
Futaki
N
N
Tanaka
Y
Y
Goto
H
H
Suga
D000818:Animals; D001699:Biometry; D001794:Blood Pressure; D003326:Coronary Circulation; D004285:Dogs; D006339:Heart Rate; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption
D010100:Oxygen