Mechano-electrical feedback explains T-wave morphology and optimizes cardiac pump function: insight from a multi-scale model.

摘要: 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 latter phenomenon, called T-wave memory, is mediated by mechanical stimulus. By means mathematical model, we investigated hypothesis slow acting mechano-electrical feedback (MEF) explains memory. our electromechanical behavior left ventricle (LV) was simulated using series mechanically electrically coupled segments. Each segment comprised ionic membrane currents, calcium handling, excitation-contraction coupling. MEF incorporated locally adjusting conductivity L-type current (g(CaL)) to local external work. set-up, g(CaL) could vary up 25%, 50%, 100% or unlimited amount around its default value. Four consecutive simulations were performed: SR (with MEF), acute VP, sustained VP acutely restored SR. led concordance in T-waves restoring Simulated ECGs with maximum 25-50% adaptation closely resembled those memory experiments in vivo also provided best compromise between optimal systolic diastolic function. conclusion, these simulation results indicate LV can explain a) relatively small differences shortening work SR, b) dispersion repolarization time, c) d) The physiological distribution electrophysiological properties, reflected T-wave, may serve optimize cardiac pump