Acute myocardial ischemia is the main cause of ventricular tachycardia and ventricular fibrillation. Reentrant activity is the most common mechanism of these ventricular arrhythmias, and is often initiated from the border zone between the ischemic and normal tissue. Theoretical studies have suggested that spiral-wave activity may be one form of reentrant arrhythmia. Our study explores the possible relation between spiral-wave activity and ischemia-induced ventricular arrhythmias. We numerically simulate reentrant activity in a two-dimensional sheet of ventricular myocardium which contains an ischemic area. We construct this ischemic area by increasing the extracellular potassium concentration in that area. When pacing the sheet with a sequence of stimuli delivered at a sufficiently high frequency, different types of spiral waves are initiated either within the ischemic area itself or in the normal area close to the ischemic boundary, depending on the potassium concentration in the ischemic area. The formation of the spiral wave is influenced by several factors such as the frequency of stimulation, the geometry of the ischemic area, and the exact level of the extracellular potassium concentration in the ischemic area. Future work should model the ischemic area more realistically with a spatially-extended border zone.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.27436 |
| Date | January 1997 |
| Creators | Xu, Aoxiang, 1969- |
| Contributors | Guerara, M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001548751, proquestno: MQ29811, Theses scanned by UMI/ProQuest. |
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