title: The mechanism of A-V conduction delay in A-V nodal gap.
abstract: Initial block in the His-Purkinje system was demonstrated in 17 of 71 patients during atrial extrastimulus testing. Of the 17 patients who demonstrated initial block in the His-Purkinje system, ten patients had A-V nodal gap (a type 1 gap). Of these ten patients, progressive increase in A-V nodal conduction was responsible for a resumption of A-V conduction in six patients, dual pathways within the A-V node was responsible in three patients, and the presence of an extra nodal pathway of the A-V node was responsible in one patient.
mesh_terms: D001281:Atrial Fibrillation / Q000503:physiopathology; D001283:Atrioventricular Node / Q000503:physiopathology*; D002036:Bundle of His / Q000503:physiopathology; D002037:Bundle-Branch Block / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D006325:Heart Atria / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D011690:Purkinje Fibers / Q000503:physiopathology; D012804:Sick Sinus Syndrome / Q000503:physiopathology; D013614:Tachycardia, Paroxysmal / Q000503:physiopathology