The arrival time and position of the activation front on the right ventricular epicardium are important information for diagnosing the site and degree of, right bundle branch block in detail. However, the smoothing of the current field within the torso results in the attenuation of the high spatial frequency components of the epicardial potential field transmitted to the body surface. Consequently, the appearance time of epicardial breakthrough obtained by inspection of body surface maps always shows a time lag of a few milliseconds. In this study, a new method has been developed to reduce this time lag. Using this new method, the appearance time of the epicardial breakthrough was obtained from the body surface by means of a 2-dimensional laplacian filter for enhancement of high spatial frequency components of the body surface potential field.
Body surface isopotential maps incorporating the characteristic patterns reflecting the epicardial breakthrough were recorded on 17 normal healthy persons using a 9×9 electrode array with an inter-electrode distance of 1. 25 cm. The results obtained by the new method and the body surface map inspection method were compared. Subsequently, simultaneous recordings of the body and epicardial surface isopotential maps were performed on 3 dogs using a 9×9 electrode array with an inter-electrode distance of 1. 5 cm for the body surface mapping and 43 electrodes for the epicardial mapping. In order to evaluate the accuracy of the new method, the values obtained were compared with the appearance times of the activation front breakthrough on the epicardial surface.
In conclusion, the appearance time Of breakthrough determined by the new filter method from the body surface was much earlier than that by the usual inspection method in human cases. The time delay with the new filter method was not significantly different from the appearance time of activation front breakthrough on the epicardial surface in dogs.
