Role of increased cholinergic activity in reperfusion induced ventricular arrhythmias

Summary: The effect of increased cholinergic activity on reperfusion induced ventricular arrhythmias was studied in alpha chloralose anaesthetised dogs by administering neostigmine during a 25 min occlusion of the anterior left descending coronary artery. The dogs were divided into five groups, each of 10 animals: the control group received only saline solution; group 1 neostigmine 0.03 mg·kg^-1 iv at 20 min of coronary occlusion (that is, 5 min before reperfusion); group 2 atropine 0.4 mg·kg^-1 iv at 10 min of coronary occlusion and neostigmine 0.03 mg·kg^-1 iv at 20 min; and group 3 neostigmine 0.03 mg·kg^-1 iv at 20 min of coronary occlusion and at the same time underwent atrial pacing at the same rate as that of the sinus node just before neostigmine administration. In group 4 heart rate was slowed (junctional rhythm) by destroying the sinus node at 20 min of coronary occlusion. The results obtained showed that ventricular tachycardia and fibrillation, which occur at the beginning of reperfusion, were significantly less frequent in group 1 (p