Using His bundle recordings and ventricular stimulation retrograde conduction was studied in 57 cases of complete AV block. VA conduction was observed in 13 patients. Of the 13, 12 had AV block distal to H, and during cardiac pacing 5 of them showed a retrograde His bundle potential. In all cases the AV node-His pathway was implicated in the transmission of the retrograde impulse. There was no ...

The three major coronary arteries of 10 normal human hearts were injected with differentially colored gelatin mass for histologic determination of the blood supply to the His bundle and proximal bundle branches. The His bundle was dually supplied by the A-V node artery and the first septal branch of the left anterior descending artery in nine hearts, but entirely by the A-V node artery in one. ...

Paroxysmal tachycardia with widened QRS complexes was recorded in a 21-year-old man. In sinus rhythm there was no evidence of pre-excitation. His bundle studies revealed an abnormally short HV interval of 30 ms. Premature atrial stimuli produced an increased PR interval. At short coupling intervals the His bundle activity became incorporated within the QRS complex. Concurrently, a left bundle-b...

A 33-year-old female was referred for an electrophysiologic study because of recurrent episodes of palpitations. Catheters were placed in the high right atrium (HRA), the His bundle (HIS), and the right ventricular apex (RVA). Baseline cycle length in sinus rhythm and atrial-His (AH) and His-ventricular (HV) intervals were 790, 90, and 45 ms, respectively. Spontaneous onset of a wide complex ta...