title: Exit block in sustained atrial tachycardia in two children.
abstract: The electrocardiographic findings in two children with sustained atrial tachycardia and exit block are reported. The exit block was dependent on the atrial pacemaker rate, being present only at rapid rates of discharge. In one case propranolol enhanced the exit block, and on an appropriate dose the heart rate was maintained within a well tolerated range.
mesh_terms: D005117:Cardiac Complexes, Premature / Q000503:physiopathology; D002675:Child, Preschool; D004562:Electrocardiography; D006325:Heart Atria / Q000503:physiopathology*; D006327:Heart Block / Q000150:complications / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D008297:Male; D013610:Tachycardia / Q000150:complications / Q000503:physiopathology*