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March 1975

The Cardiac Conduction System: Electrophysiological Studies During Open Heart Surgery

Author Affiliations

From the Department of Medicine, School of Medicine, University of Alabama in Birmingham.

Arch Intern Med. 1975;135(3):411-417. doi:10.1001/archinte.1975.00330030061007

The recording of electrograms directly from the surface of the heart in situ has been a part of many standard experimental procedures for decades. However, it is only recently that electrograms have been recorded specifically from the atrioventricular conduction system of the heart in situ. Burchell et al1 in 1953 accomplished this by using needle electrodes inserted through the epicardium. Similar recordings using needle electrodes were made in 1955 by Scher2 and in 1957 by Durrer and Van Der Tweel.3 Stuckey, Hoffman and associates4-10 then demonstrated that electrograms could be recorded from the atrioventricular conduction system of the heart in situ by local application of electrodes to the endocardial surface. Electrograms recorded from the His bundle and bundle branches were identified by their appearance during the isoelectric portion of the PR interval of a simultaneously recorded ECG lead8 (Fig 1). To obtain endocardial electrograms, they