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- Title
Intracoronary Infusion of Catecholamines Causes Focal Arrhythmias in Pigs.
- Authors
DOPPALAPUDI, HARISH; JIN, QI; DOSDALL, DEREK J.; QIN, HAO; WALCOTT, GREGORY P.; KILLINGSWORTH, CHERYL R.; SMITH, WILLIAM M.; IDEKER, RAYMOND E.; HUANG, JIAN
- Abstract
Background: Acute ischemia causes myriad changes including increased catecholamines. We tested the hypothesis that elevated catecholamines alone are arrhythmogenic. Methods and Results: A 504 electrode sock was placed over both ventricles in six open-chest pigs. During control infusion of saline through a catheter in the left anterior descending coronary artery (LAD), no sustained arrhythmias occurred, and the refractory period estimated by the activation recovery interval (ARI) was 175 ± 14 ms in the LAD bed below the catheter. After infusion of isoproterenol at 0.1 μg/kg/min through the catheter, the ARI in this bed was significantly reduced to 109 ± 10 ms. A sharp gradient of refractoriness of 43 ± 10 ms was at the border of the perfused bed. Sustained monomorphic ventricular tachycardia occurred after drug infusion in the perfused bed or near its boundary in all animals with a cycle length of 329 ± 26 ms and a focal origin. The maximum slope of the ARI restitution curve at the focal origins of the tachyarrhythmias was always <1 (0.62 ± 0.15). Similar results with a focal arrhythmia origin occurred in two additional pigs in which intramural mapping was performed with 36 plunge needle electrodes in the left ventricular perfused bed. Conclusion: Regional elevation of a catecholamine, which is one of the alterations produced by acute ischemia, can by itself cause tachyarrhythmias. These arrhythmias are closely associated with a shortened refractory period and a large gradient of the spatial distribution of refractoriness but not with a steep restitution curve.
- Subjects
ISCHEMIA; CATECHOLAMINES; CORONARY arteries; ARRHYTHMIA; TACHYCARDIA; LABORATORY swine
- Publication
Journal of Cardiovascular Electrophysiology, 2008, Vol 19, Issue 9, p963
- ISSN
1045-3873
- Publication type
Article
- DOI
10.1111/j.1540-8167.2008.01199.x