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.
Yasumura
Y
Y
Department of Cardiovascular Dynamics, National Cardiovascular Center Research Institute, Osaka, Japan.
Nozawa
T
T
Futaki
S
S
Tanaka
N
N
Goto
Y
Y
Suga
H
H
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