Serial production of controlled periods of temporary heart block used to unmask and assess latent ventricular automaticity during experimental acute myocardial ischemia
Journal of the American College of Cardiology
L V RosenshtraukhT N James
This study examined the onset, time course of development and response to overdrive stimulation of ventricular tachycardia in 10 dogs that underwent a Harris two-stage ligation of the left anterior descending coronary artery. Transient (12 +/- 3 minutes) complete atrioventricular (AV) block was produced 2, 3, 4, 5, 8, 12, 16, 20 and 24 hours after onset of infarction through selective injection of physostigmine salicylate into the AV node artery. Seven of the 10 dogs had early transient arrhythmic episodes that occurred within 20 to 40 minutes after coronary occlusion but none of the dogs had any spontaneous ventricular tachycardia in the ensuing 2 hours. Two hours after left anterior descending coronary artery ligation, complete AV block unmasked in every dog a slow (37 +/- 9 beats/min) AV junctional rhythm readily suppressed by overdrive. Three hours after coronary ligation, AV block revealed a monomorphic ventricular tachycardia (106 +/- 10 beats/min) in 3 of the 10 dogs. Four and five hours after coronary ligation, five and eight dogs, respectively, had ventricular tachycardia during AV block and in three the tachycardia was polymorphic. The two remaining dogs did not develop ventricular tachycardia during the 24 hours of o...Continue Reading
Arrhythmias are abnormalities in heart rhythms, which can be either too fast or too slow. They can result from abnormalities of the initiation of an impulse or impulse conduction or a combination of both. Here is the latest research on arrhythmias.