کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8401499 | 1544484 | 2012 | 13 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mechano-electrical feedback explains T-wave morphology and optimizes cardiac pump function: Insight from a multi-scale model
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موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
بیوفیزیک
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چکیده انگلیسی
In the ECG, T- and R-wave are concordant during normal sinus rhythm (SR), but discordant after a period of ventricular pacing (VP). Experiments showed that the latter phenomenon, called T-wave memory, is mediated by a mechanical stimulus. By means of a mathematical model, we investigated the hypothesis that slow acting mechano-electrical feedback (MEF) explains T-wave memory. In our model, electromechanical behavior of the left ventricle (LV) was simulated using a series of mechanically and electrically coupled segments. Each segment comprised ionic membrane currents, calcium handling, and excitation-contraction coupling. MEF was incorporated by locally adjusting conductivity of L-type calcium current (gCaL) to local external work. In our set-up, gCaL could vary up to 25%, 50%, 100% or unlimited amount around its default value. Four consecutive simulations were performed: normal SR (with MEF), acute VP, sustained VP (with MEF), and acutely restored SR. MEF led to T-wave concordance in normal SR and to discordant T-waves acutely after restoring SR. Simulated ECGs with a maximum of 25-50% adaptation closely resembled those during T-wave memory experiments in vivo and also provided the best compromise between optimal systolic and diastolic function. In conclusion, these simulation results indicate that slow acting MEF in the LV can explain a) the relatively small differences in systolic shortening and mechanical work during SR, b) the small dispersion in repolarization time, c) the concordant T-wave during SR, and d) T-wave memory. The physiological distribution in electrophysiological properties, reflected by the concordant T-wave, may serve to optimize cardiac pump function.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Progress in Biophysics and Molecular Biology - Volume 110, Issues 2â3, OctoberâNovember 2012, Pages 359-371
Journal: Progress in Biophysics and Molecular Biology - Volume 110, Issues 2â3, OctoberâNovember 2012, Pages 359-371
نویسندگان
Evelien Hermeling, Tammo Delhaas, Frits W. Prinzen, Nico H.L. Kuijpers,