Noninvasive imaging of ventricular activation - application to patients with WPW-syndrome

Noninvasive activation time (AT) imaging using electrocardiographic (ECG) mapping data provides information about electrical propagation through the heart with a high spatio-temporal resolution. This study presents an attempt to clinically validate AT imaging in two patients with WPW-syndrome. We acquired 62-channel ECG mapping data during treatment in the catheter laboratory. The individual torso geometry was obtained by magnetic resonance imaging. Based on this data the AT map was estimated for the entire ventricular surface off-line for validation purposes. The AT maps were computed for a pacing protocol in the region of the right ventricular apex and for sinus rhythm beats prior and after successful pathway ablation. For paced beats the first onset activation was always found to be located in the apical region of the right ventricular endocardium. For beats in sinus rhythm prior to pathway ablation the location of the first onset of activation matched with the anatomic position of the ablation catheter during successful ablation. After the treatment this spot of early basal activation disappeared in the computed AT maps. Thus, we conclude that noninvasive AT imaging from ECG mapping data presents a novel clinical tool for assessment of cardiac electrical activation In reference to the associated anatomy.