Drift of Scroll Waves in a Mathematical Model of a Heterogeneous Human Heart Left Ventricle

Rotating spiral waves of electrical excitation underlie many dangerous cardiac arrhythmias. The heterogeneity of myocardium is one of the factors that affects the dynamics of such waves. In this paper, we present results of our simulations for scroll wave dynamics in a heterogeneous model of the human left ventricle with analytical anatomically based representation of the geometry and anisotropy. We used a set of 18 coupled differential equations developed by ten Tusscher and Panfilov (TP06 model) which describes human ventricular cells based on their measured biophysical properties. We found that apicobasal heterogeneity dramatically changes the scroll wave dynamics. In the homogeneous model, the scroll wave annihilates at the base, but the moderate heterogeneity causes the wave to move to the apex and then continuously rotates around it. The rotation speed increased with the degree of the heterogeneity. However, for large heterogeneity, we observed formation of additional wavebreaks and the onset of complex spatio-temporal patterns. Transmural heterogeneity did not change the dynamics and decreased the lifetime of the scroll wave with an increase in heterogeneity. Results of our numerical experiments show that the apex may be a preferable location of the scroll wave, which may be important for development of clinical interventions.

The Pattern of Tpeak-Tend Interval and QTdis, and Pdis in Children with Brucellosis

Objective To investigate the effect of inflammation on the conducting system of the heart in patients diagnosed with brucellosis. Methods A total of 42 patients diagnosed with brucellosis and 39 age and sex-matched healthy children were enrolled into the study. Pre- and post-treatment electrocardiographic parameters in brucellosis and control group were recorded from an electrocardiogram for each patient. Results The results indicated that the parameters including Pmax, Pdis, QTmax, QTdis, QTcdis, Tp-edis interval and Tp-emax/QTmax and Tp-emax/QTcmax ratios, which are known to be key indicators for the prediction of severe atrial or ventricular arrhythmia and sudden cardiac death and also important parameters used as the indicators for the non-invasive evaluation of the transmural heterogeneity were significantly longer in the study group compared with the control group (p < 0.05). Conclusion In this study, it was determined that the brucella disease had more cardiac involvement than thought, and this was more in the subclinical form of cardiac involvement.