Evaluation of a method for quantification of restitution dispersion from the surface ECG

Spatial dispersion of action potential duration (APD) restitution (APDR) due to electrophysiological heterogeneities in the heart, has been suggested to act as a potent arrhythmogenic substrate. In this work, we evaluate a method aimed at quantifying APDR slope dispersion (Δα) from the surface electrocardiogram (ECG). A 2D human ventricular in silico tissue preparation is used, from which APDR slope dispersion (Δα^SIM) at tissue level is computed, and compared with simulated estimates calculated from pseudo-ECGs (Δ̂α^pECG). We show that Δ̂α^pECG values in our simulations are in all cases within the range of clinical values measured from tilt-test recordings. Then, we use the validated tissue model to relate the Δ̂α^pECG estimate to measurements of Δα^SIM, and we prove that the mean error is below 5%. We conclude that the proposed Δ̂α^pECG index provides valuable estimates of APDR dispersion with the advantage of being able to be measured non-invasively from the ECG.