title: Electrocardiographic manifestations of concealed junctional ectopic impulses.
abstract: Thirteen episodes of concealed junctional ectopic impulses (JEI) in ten patients are described. In nine patients the JEI manifested as isolated automatic impulses and in one as a parasystolic junctional tachycardia. In addition to the previously described unexpected prolongation of the P-R, Type I and Type II A-V block, the following phenomena were recorded: 1) marked, greater than 400 msec, and persistent prolongation of the P-R interval, 2) striking changes in the duration of the P-R with an occasional sequence of R-P and P-r intervals simulating "supernormal" A-V conduction, 3) unexpected variation of the junctional escape interval explained by junctional parasystole with entrance block, 4) postponed compensatory pause, 5) concealed junctional discharge with reciprocation.
mesh_terms: D004562:Electrocardiography; D006327:Heart Block / Q000503:physiopathology; D006329:Heart Conduction System / Q000503:physiopathology*; D006801:Humans