Effect of isoflurane on epinephrine-induced arrhythmias in ischemic-reperfused dog hearts.
Although isoflurane protects the myocardium and facilitates functional recovery after ischemia and reperfusion, its mechanism of action is still unclear. We hypothesized that isoflurane maintains intracellular Ca2+ homeostasis, thus attenuating epinephrine-induced arrhythmogenicity in in vivo models of myocardial ischemia and reperfusion. Adult mongrel dogs, anesthetized with urethane and chloralose, underwent 15 minutes of left anterior descending coronary artery occlusion followed by reperfusion. In addition to a sham group (without occlusion, n = 5) and a control group (with occlusion, n = 7), a third group (n = 5) received 1.5% isoflurane before ischemia was induced; a fourth (n = 7), isoflurane after reperfusion; and a fifth (n = 5), isoflurane and verapamil (100 micrograms/kg) after reperfusion. Isoflurane administered before ischemia increased the arrhythmogenic dose of epinephrine (ADE), but had no effect on ADE when administered after reperfusion. The addition of verapamil further increased the ADE. These results indicate that isoflurane has a cardioprotective effect during ischemia and reperfusion by, at least in part, the reduction of Ca2+ influx.
Department of Anesthesiology, Sapporo Medical University School of Medicine, Japan.
N
N
Kanaya
M
M
Nakayama
I
I
Kobayashi
S
S
Fujita
A
A
Namiki
D018685:Anesthetics, Inhalation / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000517:prevention & control*; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use*; D004285:Dogs; D004837:Epinephrine; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006706:Homeostasis / Q000187:drug effects; D007530:Isoflurane / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D015427:Reperfusion Injury / Q000188:drug therapy*; D014662:Vasoconstrictor Agents; D014700:Verapamil / Q000008:administration & dosage / Q000627:therapeutic use*
D018685:Anesthetics, Inhalation; D002121:Calcium Channel Blockers; D014662:Vasoconstrictor Agents; D014700:Verapamil; D007530:Isoflurane; D002118:Calcium; D004837:Epinephrine