Oxygen consumption of the normal and failing heart during left heart bypass.

In order to determine whether myocardial oxygen consumption (MOC) is decreased during left heart bypass (LHB), two groups of 6 dogs each were subjected to 2 hours of heparinless LHB. Group 2 differed from Group 1 in that cardiogenic shock was induced by temporary coronary artery occlusion prior to LHB. In Group 1 animals (normal dogs), MOC decreased significantly during the surgical preparation but did not change appreciably during subsequent LHB.