Effect of physiological changes in Heart Rate Turbulence using a lumped parameter model

Heart Rate Turbulence (HRT) is a strong risk stratification criterion in patients with cardiac disorders. Several physiological factors affect HRT, e.g., previous heart rate, circadian rhythm. However, the relationship between these factors and HRT still needs to be further clarified. We propose to use a modified version of a detailed lumped parameter model to study the relationship between different physiological factors and the HRT, as quantified by the usual Turbulence Slope (TS) and Turbulence Onset (TO) parameters. We modified a detailed model of cardiac regulation previously developed by Ursino and Magosso, in order to generate the hemodynamic effect of ectopic beats and the subsequent HRT response. The modified version of the model allows to vary three different physiological factors, namely, prematurity, maximum contraction and systole duration of the ectopic beat. Changes in these physiological factors modify the resulting HRT pattern. These results should be taken into account when quantifying HRT by TS and TO parameters, just as the ulterior risk stratification procedure using them.