Computational modeling of human fetal normal sinus rhythm and arrhythmia

Non-invasive measures of the fetal ECG provide quantitative information on pacemaking rate, propagation times and velocities during normal sinus rhythm. One dimensional partial differential equation models of propagation that reproduce fetal normal sinus rhythm in hearts from 16-40 weeks gestational age were constructed Lengths were obtained from magnetic resonance imaging data, intercellular coupling informed by ECG timings, and cell excitation described by modified models for adult human cardiac cells. Spatially uniform progressive reduction of the L-type calcium conductance slowed the rate, and led to atrioventricular conduction blocks. Self terminating and persistent re-entry with a period of 240 - 300ms could be produced within a 1-D ring ventricular tissue model. The preliminary 1-D family of models quantitatively reproduces the observed timings of fECG intervals from 16-40 WGA, and predicts the characteristics of development of fetal A V block, and self terminating ventricular tachycardia.