Differences in non-invasive imaging of atrial and ventricular recovery

Non-invasive imaging of cardiac activation and recovery based on the equivalent double layer source model is a non-linear and ill-posed problem. The problem involved is cast in the form of a non-linear parameter estimation, requiring an initial estimate and regularized minimization. While focusing on the estimation of the timing of repolarization, we compared the effect of applying the regularization to either the timing of recovery or to the activation recovery interval (ARI). The results suggest that regularizing the ARI is to be preferred in the estimation of the timing of recovery of the atria as well as of the ventricles.