Arrhythmogenic effects of carbon monoxide in experimental acute myocardial ischemia: lack of slowed conduction and ventricular tachycardia.
To investigate the possibility that carbon monoxide (CO) at high clinically encountered levels may have arrhythmogenic effect in initial minutes of acute myocardial ischemia, 14 dogs underwent thoracotomy and recording of bipolar epicardial electrograms during brief (6-minute) left anterior descending coronary artery (LAD) occlusions. Eight of the 14 dogs were studied both before and after CO pretreatment in which carboxyhemoglobin levels of 6.8% to 14.6% (mean 10.4 +/- 2.8%) were achieved. Epicardial electrograms showed no change in degree of ischemic myocardial conduction slowing after CO, and there was no significant difference between CO and no-CO LAD occlusions in incidence of spontaneous ventricular tachycardia. Since the degree of myocardial conduction slowing is thought to be importantly related to susceptibility to ventricular arrhythmias in acute ischemia, this study suggests that CO may not be arrhythmogenic during early minutes of acute myocardial ischemia.
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000503:physiopathology*; D002248:Carbon Monoxide / Q000633:toxicity*; D002263:Carboxyhemoglobin / Q000032:analysis; D004285:Dogs; D004562:Electrocardiography; D006329:Heart Conduction System / Q000187:drug effects*; D006352:Heart Ventricles / Q000187:drug effects; D009203:Myocardial Infarction / Q000503:physiopathology*
D002248:Carbon Monoxide; D002263:Carboxyhemoglobin