Impact of the Transmural Dimension of Infarction Scar on the Dynamics of Spiral Waves in Realistic Models of the Human Heart's Left Ventricle

Three-dimensional spiral waves (vortices or scroll waves (SWs)) of electrical excitation in the myocardium can induce cardiac arrhythmia. The time-dependent dynamics of an SW determines scenario and type of arrhythmia development. It is known that the structural and functional heterogeneity of myocardial tissue is one of the major factors affecting SW drift, especially if the heterogeneity increases significantly due to tissue remodeling after myocardial infarction (MI). In this work, we investigated SW dynamics in anatomically realistic models of the left ventricle (LV) of the human heart, depending on LV geometry and on the transmural dimension of the MI scar in the LV wall. We built two population models of LV geometry based on echocardiographic LV images: a model of normal LV geometry and a model of pathological LV geometry. In the absence of the MI scar, the SWs were stable independently of the model geometry. In the LV models with MI scars, the dynamics of SWs depended on the LV geometry and transmurality of MI scar. In all cases, the SW drifted toward MI zone. New waves then appeared, which led to three effects: the annihilation of spiral waves, LV fibrillation, the anchoring of spiral waves around the scar area.