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Intracoronary Infusion of Catecholamines Causes Focal Arrhythmias in Pigs
Author(s) -
DOPPALAPUDI HARISH,
JIN QI,
DOSDALL DEREK J.,
QIN HAO,
WALCOTT GREGORY P.,
KILLINGSWORTH CHERYL R.,
SMITH WILLIAM M.,
IDEKER RAYMOND E.,
HUANG JIAN
Publication year - 2008
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2008.01199.x
Subject(s) - medicine , refractory period , cardiology , ventricular tachycardia , catheter , ventricular fibrillation , saline , anesthesia , ischemia , tachycardia , surgery
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.