The shortest path to cardiac activation

Contains fulltext : 74933.pdf (Publisher’s version ) (Open Access) This thesis describes the application of the shortest path algorithm in the simulation of cardiac activation. This method is both used in the forward simulation of an electrocardiogram (ECG) as well as in the non-invasive imaging of cardiac activation and recovery. Due to the immense number of cardiac cells a source model is required to simulate the electrical cardiac generator. The source model used in this thesis is the equivalent double layer source model. One of the major advantages of this model is the close relation with electrophysiological characteristics of the cardiac cells. This enables the introduction of electrophysiological knowledge in the require initial estimate on behalf of the non-invasive imaging method. Knowledge on the propagation of activation within the myocardial tissue was introduced to generate realistic activation patterns, both for the atria and the ventricles. The inverse procedure described in this thesis proves to be robust, both in respect to the number of leads used and to the waveform parameterization used in the source model. The robustness is mainly attributed to the high quality of the initial activation estimate based on the dedicated implementation of the shortest path algorithm, the fastest route algorithm. This results in an initial estimate that is close to the actual activation and recovery times, which minimize the risk that the subsequently applied inverse procedure ends up in an unrealistic local minimum in the parameter space. The clinical application of this inverse procedure is now coming within reach. Selecting the optimal lead system might enable the inverse procedure to be executed by using a limited number of leads (15-30). For specific cases and research applications, like shown for the Brugada patient, the proposed non-invasive imaging method seems to have reached maturity. RU Radboud Universiteit Nijmegen, 05 februari 2010 Promotor : Oosterom, A. van Co-promotor : Oostendorp, T.F. 119 p.