The Mechanism of Reflection Type Reentry: A Simulation Study.
BACKGROUND
Reflection is a special type of reentry in which an electrical wave front travels in a forward direction through tissue that is then re-excited by a wave front that propagates backward. This type of reentry has been studied computationally in 1-dimensional fibers and verified experimentally. Different hypotheses explaining reflected reentry have been proposed based on the structure and heterogeneity of the tissue properties, but the mechanism remains uncertain.


RESULTS
We used the bidomain model to represent cardiac tissue and the Luo-Rudy model to describe the active membrane properties. We consider an ischemic region in a volume of ventricular myocardium. Our results show that a slow depolarization in the ischemic border zone caused by electrotonic coupling to depolarized tissue in the normal region creates a delay between proximal and distal regions that produces enough electrotonic current in the distal region to re-excite the proximal region.


CONCLUSIONS
Our simulation shows that an early afterdepolarization (EAD) is not the source of the reflection. It depends on the pacing interval and stimulus strength necessary to maintain enough time delay between proximal and distal regions.
Department of Physics, Oakland University, Rochester, Michigan.
Sunil M
SM
Kandel
Department of Physics, Oakland University, Rochester, Michigan.
Bradley J
BJ
Roth
D002462:Cell Membrane; D003198:Computer Simulation; D004558:Electric Stimulation; D006321:Heart / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008564:Membrane Potentials; D008955:Models, Cardiovascular; D017202:Myocardial Ischemia / Q000150:complications / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D011188:Potassium / Q000378:metabolism; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000473:pathology / Q000503:physiopathology*
D011188:Potassium
Luo-Rudy model; bidomain model; electrotonic current; reentry; reflection