title: Supernormality with cycle length-dependent intra-His alternans: a new cause of group beating.
abstract: This article describes a patient with baseline infranodal conduction disease. Following the administration of intravenous procainamide, the patient developed group beating. Careful electrophysiological evaluation revealed that the group beating was due to alternating intra-His conduction times. Systematic analysis of paced and spontaneous events provides strong evidence that the alternans results from supernormality within the His bundle.
authors.affiliation: Department of Cardiology, Cleveland Clinic Foundation, Ohio, USA.
authors.forename: R G
authors.initials: RG
authors.lastname: Trohman
authors.forename: S L
authors.initials: SL
authors.lastname: Pinski
mesh_terms: D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D001145:Arrhythmias, Cardiac / Q000503:physiopathology*; D002036:Bundle of His / Q000503:physiopathology*; D004562:Electrocardiography; D006327:Heart Block / Q000503:physiopathology; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D011342:Procainamide / Q000008:administration & dosage
chemical_list: D000889:Anti-Arrhythmia Agents; D011342:Procainamide