title: Concealed his bundle extrasystoles in congenital heart disease.
abstract: His bundle electrograms were recorded in two children with cardiac conduction disturbances. In the surface electrocardiograms of one patient His bundle extrasystoles mimicked atrial nonconducted bigeminal rhythms; in the other, they simulated second degree atrioventricular (A-V) block and conducted junctional extrasystoles. In both instances the conduction disturbance was a result of concealed conduction of the His bundle extrasystole into the A-V junction. We conclude that the surface electrocardiogram is suggestive but not definitive in diagnosing His bundle extrasystoles and that His bundle recordings are indispensable for correct diagnosis and treatment.
mesh_terms: D002036:Bundle of His; D005117:Cardiac Complexes, Premature / Q000175:diagnosis* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D003914:Dextrocardia / Q000150:complications; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000175:diagnosis; D006329:Heart Conduction System / Q000503:physiopathology; D006330:Heart Defects, Congenital / Q000150:complications*; D006333:Heart Failure / Q000150:complications; D006801:Humans; D013771:Tetralogy of Fallot / Q000150:complications