Modeling ventricular repolarization: effects of transmural and apex-to-base heterogeneities in action potential durations
Articolo
Data di Pubblicazione:
2008
Citazione:
Modeling ventricular repolarization: effects of transmural and apex-to-base
heterogeneities in action potential durations / P. Colli Franzone, L. F. Pavarino, S. Scacchi, B. Taccardi. - In: MATHEMATICAL BIOSCIENCES. - ISSN 0025-5564. - 214:1(2008), pp. 140-152. [10.1016/j.mbs.2008.06.006]
Abstract:
Heterogeneities in the densities of membrane ionic currents of myocytes cause regional variations in action potential duration (APD) at various intramural depths and along the apico-basal and circumferential directions in the left ventricle. This work extends our previous study of cartesian slabs to ventricular walls shaped as an ellipsoidal volume and including both transmural and apex-to-base APD heterogeneities. Our 3D simulation study investigates the combined effect on repolarization sequences and APD distributions of: (a) the intrinsic APD heterogeneity across the wall and along the apex-to-base direction, and (b) the electrotonic currents that modulate the APDs when myocytes are embedded in a ventricular wall with fiber rotation and orthotropic anisotropy. Our findings show that: (i) the transmural and apex-to-base heterogeneities have only a weak influence on the repolarization patterns on myocardial layers parallel to the epicardium; (ii) the patterns of APD distribution on the epicardial surface are mostly affected by the apex-to-base heterogeneities and do not reveal the APD transmural heterogeneity; (iii) the transmural heterogeneity is clearly discernible in both repolarization and APD patterns only on transmural sections; (iv) the apex-to-base heterogeneity is clearly discernible only in APD patterns on layers parallel to the epicardium. Thus, in our orthotropic ellipsoidal wall, the complex 3D electrotonic modulation of APDs does not fully mix the effects of the transmural and apex-to-base heterogeneity. The intrinsic spatial heterogeneity of the APDs is unmasked in the modulated APD patterns only in the appropriate transmural or intramural sections. These findings are independent of the stimulus location (epicardial, endocardial) and of Purkinje involvement.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Action potential duration; Cardiac Monodomain and Bidomain models; Myocardial heterogeneity; Parallel numerical simulations; Reaction-diffusion equations; Repolarization sequence
Elenco autori:
P. Colli Franzone, L.F. Pavarino, S. Scacchi, B. Taccardi
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