Distribution of extracellular potassium and electrophysiologic changes during two-stage coronary ligation in the isolated, perfused canine heart.

Abstract

We studied the relation between [K+]o and the electrophysiologic changes during a "Harris two-stage ligation," which is an occlusion of a coronary artery, preceded by a 30-minute period of 50% reduction of flow through the artery. This two-stage ligation has been reported to be antiarrhythmic. Local direct current electrograms and [K+]o signals from up to 48 intramural sites were simultaneously recorded in isolated, perfused dog hearts. A second period of one-stage ligation was compared with a consecutive two-stage ligation because reproducibility in [K+]o and electrophysiologic changes are established only after the first period of ischemia. In control experiments, no difference was found between the second and third period of one-stage ligation in the electrophysiologic changes and in increases in [K+]o. After complete occlusion during two-stage ligation, activation block in the ischemic tissue occurred about 6 minutes earlier than during one-stage ligation, but the average potassium concentration at which block occurred was identical. This [K+]o during total ischemia was achieved earlier during two-stage ligation than during one-stage ligation. No indication was found for a large decrease of intracellular potassium content during the period of low flow perfusion. Early activation block may explain the previously reported reduced incidence of ventricular fibrillation during two-stage ligation.

• Authors: R Coronel, J W Fiolet, J G Wilms-Schopman, T Opthof, A F Schaapherder, M J Janse
• Journal: Circulation (Circulation) Vol. 80 Issue 1 Pg. 165-77 (Jul 1989) ISSN: 0009-7322 [Print] United States
• PMID: 2736748 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Potassium

Topics

• Animals
• Constriction, Pathologic
• Coronary Circulation
• Coronary Disease (physiopathology)
• Coronary Vessels
• Dogs
• Electrophysiology
• Extracellular Space (metabolism)
• Heart (physiology)
• In Vitro Techniques
• Ligation
• Myocardium (metabolism)
• Osmolar Concentration
• Perfusion
• Potassium (metabolism)
• Tissue Distribution