| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
1 Medicine, Research Center, University of Montreal, Montreal Heart Institute, Montreal, Quebec, Canada
2 Medicine, Research Center, University of Montreal, Montreal Heart Institute, Montreal, Quebec, Canada; Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
3 Electrical Engineering, University of Calgary, Calgary, Alberta, Canada
* To whom correspondence should be addressed. E-mail: stanley.nattel{at}icm-mhi.org.
Tissue size has been considered an important determinant of atrial fibrillation (AF), but recent work has questioned the critical size hypothesis. Here, we use a previously-developed mathematical model of two-dimensional canine atrium with realistic action potential, ionic and conduction properties to address substrate size effects on maintenance of fibrillatory activity. Cholinergic AF was simulated at different acetylcholine concentrations and distributions, with substrate area varied 11.1-fold. Automated phase-singularity detection was used to facilitate analysis of arrhythmic activity. The duration of activity induced by a single extrastimulus increased with increasing substrate dimensions. Two general mechanisms underlying activity were observed and were differentially affected by substrate size. For large mean acetylcholine-concentrations, single primary rotors anchored in low acetylcholine-concentration zones maintained activity and substrate dimensions were not critical. At lower mean-acetylcholine concentrations, extensive spiral-wave meander prevented the emergence of single stable rotors. Prolonged activity was favored when substrate size permitted a sufficiently large number of simultaneous longer-lasting rotors that extinction of all was unlikely. Thus, either single dominant-rotor or multiple reentrant spiral-generator mechanisms could maintain fibrillatory activity in this model, and were differentially dependent on substrate size. These results speak to recent debates about the role in AF of single driver rotors versus multiple reentrant circuit mechanisms, by suggesting that either may maintain fibrillatory atrial activity depending on atrial size and electrophysiological properties.
This article has been cited by other articles:
|
|
 |
|
  K. Nishida, G. Michael, D. Dobrev, and S. Nattel Animal models for atrial fibrillation: clinical insights and scientific opportunities Europace, October 29, 2009; (2009) eup328v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Nattel, B. Burstein, and D. Dobrev Atrial Remodeling and Atrial Fibrillation: Mechanisms and Implications Circ Arrhythm Electrophysiol, April 1, 2008; 1(1): 62 - 73. [Full Text] [PDF]
|
|
|
|
 |
|
 G. Laurent, G. Moe, X. Hu, H. Leong-Poi, K. A. Connelly, P. P.-S. So, A. Ramadeen, L. Doumanovskaia, A. Konig, J. Trogadis, et al. Experimental studies of atrial fibrillation: a comparison of two pacing models Am J Physiol Heart Circ Physiol, March 1, 2008; 294(3): H1206 - H1215. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Ono, H. Hayashi, A. Kawase, S.-F. Lin, H. Li, J. N. Weiss, P.-S. Chen, and H. S. Karagueuzian Spontaneous atrial fibrillation initiated by triggered activity near the pulmonary veins in aged rats subjected to glycolytic inhibition Am J Physiol Heart Circ Physiol, January 1, 2007; 292(1): H639 - H648. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. P. Nash, C. P. Bradley, P. M. Sutton, R. H. Clayton, P. Kallis, M. P. Hayward, D. J. Paterson, and P. Taggart Whole heart action potential duration restitution properties in cardiac patients: a combined clinical and modelling study Exp Physiol, March 1, 2006; 91(2): 339 - 354. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. R. Efimov and V. V. Fedorov Chessboard of atrial fibrillation: reentry or focus? Single or multiple source(s)? Neurogenic or myogenic? Am J Physiol Heart Circ Physiol, September 1, 2005; 289(3): H977 - H979. [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH |
| Visit Other APS Journals Online |
