Title :
Changes in myocardial impedance spectrum during acute ischemia in the in-situ pig heart
Author :
Bragós, R. ; Riu, P.J. ; Warren, M. ; Tresànchez, M. ; Carreño, A. ; Cinca, J.
Author_Institution :
Dept. d´´Eng. Electron., Univ. Politecnica de Catalunya, Barcelona, Spain
fDate :
31 Oct-3 Nov 1996
Abstract :
In-vivo monitoring of myocardial impedance during ischemia is useful to study the pathophysiological changes occurring after coronary occlusion and to assess tissue damage. Ischemic myocardium impedance spectrum (1 kHz-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 whereas 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 double step change with time of the myocardium electrical impedance at 1 kHz
Keywords :
bioelectric phenomena; biomedical measurement; cardiology; electric impedance measurement; muscle; 1 kHz to 1 MHz; 140 min; 30 min; acute ischemia; central frequency; coronary occlusion; double relaxation mechanism; double step change; first relaxation; in-situ pig heart; left anterior descending coronary artery occlusion; medical research; myocardial impedance spectrum changes; myocardium electrical impedance; open chest chloralose anesthesized pig model; relaxation arcs; tissue damage assessment; Biological control systems; Cables; Electrodes; Frequency; Heart; Impedance measurement; In vivo; Ischemic pain; Myocardium; Probes;
Conference_Titel :
Engineering in Medicine and Biology Society, 1996. Bridging Disciplines for Biomedicine. Proceedings of the 18th Annual International Conference of the IEEE
Conference_Location :
Amsterdam
Print_ISBN :
0-7803-3811-1
DOI :
10.1109/IEMBS.1996.646336
