Effect of resistive barrier location on the relationship between T-wave alternans and cellular repolarization alternans: a 1-D modeling study.
Structural inhomogeneities in cardiac tissue have been associated with increased cellular repolarization alternans in animal experiments and increased T-wave alternans (TWA) in clinical studies. However, the effect of structural inhomogeneities on the relationship between cellular alternans and TWA has not been thoroughly investigated. We created 1-dimensional multicellular fiber models with and without a resistive barrier in various fiber regions and paced each model to induce cellular alternans. The models demonstrate that a resistive barrier in one fiber region substantially alters cellular repolarization alternans throughout the fiber. A midmyocardial or subepicardial barrier increase both TWA amplitude and maximum cellular alternans magnitude, relative to a fiber without a barrier. In addition, a direct relationship exists between TWA amplitude and maximum cellular alternans magnitude, which was highly dependent on barrier location. These results suggest that the position of a structural inhomogeneity within the myocardium may have substantial effects on dynamic repolarization instability and arrhythmogenicity.
Department of Biomedical Engineering, Duke University, Durham, NC 27708-0281, USA. ashish.doshi@duke.edu
Ashish N
AN
Doshi
Salim F
SF
Idriss
D000200:Action Potentials; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D004562:Electrocardiography / Q000379:methods*; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans; D008955:Models, Cardiovascular; D032383:Myocytes, Cardiac; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology*