Effects of inotropic drugs on mechanical function and oxygen balance in postischemic canine myocardium: comparison of dobutamine, epinephrine, amrinone, and calcium chloride.
Brief ischemic episodes that induce myocardial and coronary endothelial dysfunction may alter the responses to inotropic drugs. To determine the effects of inotropic drugs in stunned myocardium, the coronary blood flow (CBF), myocardial oxygen consumption (MVO2), and regional mechanical function in response to intracoronary dobutamine, epinephrine, amrinone, and calcium chloride (CaCl2) were measured before (normal) and 30 min after a 15-min-period occlusion of the left anterior descending artery (stunned) in an open-chest canine model. Percent segment shortening (%SS) and post-systolic shortening (%PSS) were determined. Myocardial extraction of oxygen (EO2) and lactate (E(lac)) was calculated. The inotropic drugs increased %SS, CBF, and MVO2 in normal myocardium. Epinephrine and amrinone decreased, while dobutamine and CaCl2 did not affect EO2. The ischemia and reperfusion itself significantly reduced %SS and E(lac), and increased %PSS. In stunned myocardium, the responses to inotropic drugs were not significantly altered, except that they progressively reduced %PSS and epinephrine did not affect EO2. These findings indicate that a brief episode of ischemia does not affect the mechanical and metabolic coronary flow responses to inotropic drugs, although it abolishes direct vasodilator responses to epinephrine.
Yoo
Kyung Yeon
KY
Department of Anesthesiology, Chonnam National University Medical School, Gwangju, Korea. kyyoo@chonnam.chonnam.ac.kr
Kim
Hyeun
H
Jeong
Cheol Won
CW
Park
Heon Chang
HC
Bae
Hong Beom
HB
Lee
JongUn
J
D000676:Amrinone / Q000008:administration & dosage; D000818:Animals; D002122:Calcium Chloride / Q000008:administration & dosage; D002316:Cardiotonic Agents / Q000008:administration & dosage*; D004280:Dobutamine / Q000008:administration & dosage; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000008:administration & dosage; D005260:Female; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D017682:Myocardial Stunning / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology*; D010084:Oxidation-Reduction / Q000187:drug effects; D010101:Oxygen Consumption / Q000187:drug effects*; D015427:Reperfusion Injury / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology*; D016896:Treatment Outcome
D002316:Cardiotonic Agents; D004280:Dobutamine; D000676:Amrinone; D002122:Calcium Chloride; D004837:Epinephrine