Anode make and break excitation mechanisms and strength-interval curves: Bidomain simulations in 3D rotational anisotropy

The shape of anodal strength-interval curves and make and break excitation mechanisms are investigated in a 2D anisotropic Bidomain model, with different membrane models and action potential durations, and in a 3D rotational anisotropic Bidomain model, with axisymmetric or orthotropic conductivity properties. The results have shown that the LRd model with a long intrinsic APD exhibits a systolic dip threshold lower than the diastolic threshold, in agreement with previous experimental data. The spatial and temporal analysis of the excitation patterns indicates a novel anode make excitation mechanism with delayed propagation within the transition from break to make mechanisms.