Changes in myocardial impedance spectrum during acute ischemia in the in-situ pig heart.

Authors: Bragos, R. Riu, P.J. Warren, M. Tresanchez, M. Carreņo, A. Cinca, J.

Journal:Conference Proceedings ...

Conf. title:18 th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. Conf date: 31st Oct.- 3th Nov. 1996 Conf. Loc.: Amsterdam, The Netherlands.

Abstract: In-Vivo monitoring of myocardial impedance during ischemia is useful to study the pathophysiological changes occuring after coronary occlusion and to assess tissue damage. Ischemic myocardium impedance spectrum (1kHz- 1 MHz) was measured during 140 min of left anterior descending (LAD) coronary artery occlusion in the open chest chloralose anesthesized pig model. The impedance spectrum shows a double relaxation mechanism. The first relaxation has a central frequency around 300 kHz wereas the second is around 10 kHz and appears after approx 30 min of ischemia becoming dominant thereafter. The complex plane plot shows a radius increase of both relaxation arcs. This behaviour could explain the reported time course of the myocardium electrical impedance at 1kHz.