title: Catheter-induced A-V nodal block occurring during electrophysiologic study.
abstract: We describe a patient who underwent electrophysiologic study for evaluation of recurrent syncope. No abnormalities were found but high-grade A-V block proximal to the His bundle depolarization developed abruptly as the coronary sinus electrode catheter was being withdrawn. The A-V block disappeared gradually over a 12-hour period, progressing to type I second-degree A-V block, and then to first-degree A-V block (due to prolonged A-V nodal conduction), prior to resuming normal conduction. We postulate that A-V block was induced by direct contact between the electrode catheter and the A-V node or very proximal His bundle. Catheter-induced A-V block at this site has been described only rarely, possibly because of the relatively protected location and the configuration of the A-V node.
mesh_terms: D000328:Adult; D001283:Atrioventricular Node; D002036:Bundle of His; D006328:Cardiac Catheterization / Q000009:adverse effects; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D004594:Electrophysiology; D005260:Female; D006327:Heart Block / Q000209:etiology*; D006801:Humans; D013575:Syncope / Q000175:diagnosis