The feasibility of detecting His-bundle activity from the body surface.

Electrocardiograms were recorded from human patients using a bipolar chest lead together with simultaneous His-bundle electrograms. These were then subjected to the technique of signal averaging in an attempt to extract His-bundle activity from the surface record. This was successful in three out of 10 cases subjected to the truly non-invasive surface technique. Methods are discussed by which the technique could be improved.