title: Amiodarone-induced intra-His block.
abstract: Two patients, one with and one without preexisting conduction system abnormalities, were treated with amiodarone for refractory ventricular arrhythmias. Electrophysiologic testing before and during amiodarone therapy revealed amiodarone-induced HV interval prolongation and second degree intra-His Wenckebach block with no change in QRS configuration during atrial pacing at relatively long cycle lengths. The mechanism responsible for this phenomenon is unclear. These cases illustrate that amiodarone can induce distal conduction system block even in the absence of clinical conduction system disease in a pattern that mimics atrioventricular nodal block.
mesh_terms: D000368:Aged; D000638:Amiodarone / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000503:physiopathology; D001283:Atrioventricular Node / Q000187:drug effects / Q000503:physiopathology; D001572:Benzofurans / Q000009:adverse effects*; D002036:Bundle of His / Q000187:drug effects* / Q000503:physiopathology; D004562:Electrocardiography; D006327:Heart Block / Q000139:chemically induced* / Q000503:physiopathology; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D008297:Male
chemical_list: D001572:Benzofurans; D000638:Amiodarone