PMID: 8305986Dec 1, 1993Paper

Effect of rate on changes in conduction velocity and extracellular potassium concentration during acute ischemia in the in situ pig heart

Journal of Cardiovascular Electrophysiology
J R HarperL S Gettes

Abstract

The purpose of our study was to determine if the slowing of longitudinal intraventricular conduction in the in situ porcine heart during acute regional no-flow ischemia was rate dependent. Further, we investigated whether any rate dependence could be correlated to a rate-dependent component of the ischemia-induced rise in extracellular potassium concentration, [K+]e. We studied in situ hearts in nine anesthetized open chest pigs in which acute no-flow ischemia was induced by occlusion of the left anterior descending coronary artery. To determine the effects of steady-state rate on the slowing of conduction and rise in [K+]e during ischemia, we varied the rate of stimulation during sequential occlusions from 90 to 150 beats/min. Longitudinal conduction velocity was determined by unipolar electrodes embedded in a plaque that was sutured to the epicardial surface in the center of the ischemic zone. Myocardial [K+]e was determined simultaneously by potassium-sensitive electrodes placed at or within 1 to 2 mm of the epicardium in close proximity to the activation recording electrodes. Conduction velocity decreased more rapidly at the more rapid rates of stimulation although the reduction in conduction velocity occurring prior to the...Continue Reading

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Citations

Aug 16, 2001·The Anatomical Record·N HuE B Clark
Apr 3, 2012·American Journal of Physiology. Heart and Circulatory Physiology·Elizabeth M CherryRobert F Gilmour
May 7, 2016·International Heart Journal·Ichiro Watanabe, Leonard S Gettes
May 18, 2001·American Journal of Physiology. Heart and Circulatory Physiology·J Wu, D P Zipes

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