Negative inotropic action of propofol is enhanced in the acute ischemic myocardium of dogs.
OBJECTIVE
We investigated the effects of propofol on contractility and oxygen balance in acute ischemic myocardium and compared them with those of normal myocardium using a coronary microembolization model in dogs.


METHODS
In open-chest dogs, the left anterior descending coronary artery (LAD) was perfused through an extracorporeal bypass from the carotid artery. Regional myocardial contractility and myocardial oxygen balance were evaluated along with segment shortening (%SS), regional myocardial oxygen consumption (MVO2), and lactate extraction ratio (LER) of the area perfused by the LAD. Acute ischemia was produced by repeated injection of microspheres into the LAD-perfused area until %SS decreased by 50% of baseline.


RESULTS
In normal myocardium, intracoronary infusion of propofol at doses of 1.2 and 2.4 mg x kg(-1) x h(-1) caused slight decreases in %SS to 83% +/- 8% and 80% +/- 10%, respectively. In ischemic myocardium, propofol caused greater decreases in %SS (59% +/- 18% and 35% +/- 20%, respectively). The changes in MVO2 after propofol infusion generally paralleled the changes in %SS, but LER was not changed in either ischemic or normal myocardium.


CONCLUSIONS
Propofol causes a greater decrease in the contractility of acute ischemic myocardium as compared with normal myocardium in which myocardial oxygen imbalance is not involved as a mechanism.
Maekawa
Takuji
T
Department of Anesthesiology, Nagasaki University School of Medicine, 1-7-1 Sakamoto, Nagasaki 852-8501, Japan.
Cho
Sungsam
S
Takahashi
Shunji
S
Hara
Tetsuya
T
Tomiyasu
Shiro
S
Makita
Tetsuji
T
Sumikawa
Koji
K
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002560:Cerebrovascular Circulation / Q000187:drug effects; D002698:Chloralose / Q000494:pharmacology; D003864:Depression, Chemical; D004285:Dogs; D009200:Myocardial Contraction / Q000187:drug effects*; D009203:Myocardial Infarction / Q000503:physiopathology*; D010101:Oxygen Consumption / Q000187:drug effects; D015742:Propofol / Q000494:pharmacology*
D002698:Chloralose; D002118:Calcium; D015742:Propofol