title: The effect of phentolamine on conduction in the bundle of His.
abstract: A His bundle electrogram was obtained in a 65 year old male with syncopal episodes. A split bundle of His deflection was recorded. After the intravenous administration of phentolamine, a marked shortening of the H-H' interval was observed. This signifies an improvement in conduction at the bundle of His level.
mesh_terms: D000368:Aged; D002036:Bundle of His / Q000187:drug effects*; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008297:Male; D010646:Phentolamine / Q000494:pharmacology*; D013575:Syncope / Q000503:physiopathology*
chemical_list: D010646:Phentolamine