The use of simultaneous multichannel endocardial and surface electrocardiograms for verification of exit site localization using body surface mapping

Exit sites of monomorphic ventricular tachycardia and focal sites of ventricular extrasystoles can be localized using an endocardial catheter in conjunction with a multichannel surface ECG, in order to find a suitable site for ablation. For this procedure, as well as for the diagnosis of these types of arrhythmia it is desirable to know the relation between surface ECG and site of origin accurately. This knowledge can be provided by endocardial pacing on well-known sites and recording the resulting ECG, but this method is hampered by the low resolution of catheter localization techniques, breathing of the patient, and cardiac motion. By pacing on an endocardial basket catheter, that has 64 electrodes, and simultaneously recording of the endocardial and body-surface leads, we may obtain useful data to establish the relation between pacing site, endocardial activation spreading, and surface ECG. These data can be used to create and verify localization methods for ectopic and paced beats. In this paper, we investigate the stability of basket-paced beats and localization results.