Methods for initialization of activation based inverse electrocardiography using graphs derived from heart surface geometry

The activation-based inverse problem of electrocardiography is non-linear in the desired activation times. Current solutions rely on iterative algorithms. There is considerable interest in improved initialization approaches due to the importance of the initialization used. Recent efforts include the critical point algorithm of Huiskamp and Green-site and the fastest route algorithm of van Dam, Oostendorp, and van Oosterom. In this work we analyze the relationship between these two methods. We also suggest an alternative to the shortest path approach to represent the set of likely activation patterns that may have computational advantages. We also explore modifications to these two methods exploiting their relationship and using the new activation patterns. We use epicardially stimulated data and geometries, recorded at the Cardiovascular Research and Training Institute in Utah, and geometries and forward matrix supplied with the ECGSim software, to compare results.