A Case of Complete A-V Block due to Intra-His Block

ABSTRACT

His bundle recordings enable us to diagnose conduction disturbances not discernable in the standard leads, and to localize conduction block in the subdivisions of the conduction system. Cases of intra-His bundle block were first reported in 1970 by Narula and Samet. Thereafter many additional reports and studies were made. We report a case of 3degrees A-V block due to conduction block at the His bundle level. A 71-year-old woman was admitted because of dizziness. Surface ECG showed 3degrees A-V block. His bundle electrogram revealed typical split His potential. A-H intervals were 80 msec and H'-V intervals 50~70 msec. And there found no relation between AH and H'A. Atrial pacing resulted only prolongation of A-H to 90 msec but dissociation between h and H' was consistent. We implanted a permanent endocardial pacemaker in her chest.