title: Dual atrioventricular-nodal physiology, elicited by pacing and leading to a reversible cardiomyopathy.
abstract: Atrioventricular nodal re-entry tachycardia is the most common form of regular paroxysmal tachycardia in the adult population. This tachycardia is a re-entrant rhythm that uses the anatomic location of the atrioventricular node and its surrounding perinodal atrial tissue. The simplest concept regarding the atrioventricular nodal physiology that allows re-entry is founded upon the postulated existence of 2 atrioventricular nodal pathways with different conduction velocities and refractory periods. Herein, we present the case of a 64-year-old man who had a history of paroxysmal atrial fibrillation; he had a permanent pacemaker for sick-sinus syndrome. He developed a tachycardia-induced cardiomyopathy with a perpetual dual response to the pacemaker stimulus. The tachycardia displayed characteristic dual atrioventricular-nodal physiology that was suppressed by amiodarone therapy, leading to a reversal of the cardiomyopathy. We discuss the mechanisms that surround such phenomena.
authors.affiliation: Department of Cardiology, Division of Electrophysiology, North Shore University Hospital, Manhasset, New York 11030, USA.
authors.forename: John N
authors.initials: JN
authors.lastname: Catanzaro
authors.forename: John
authors.initials: J
authors.lastname: Makaryus
authors.forename: Jonathan
authors.initials: J
authors.lastname: Vafai
authors.forename: Amgad N
authors.initials: AN
authors.lastname: Makaryus
authors.forename: Ram
authors.initials: R
authors.lastname: Jadonath
authors.forename: Stuart
authors.initials: S
authors.lastname: Beldner
mesh_terms: D000638:Amiodarone / Q000627:therapeutic use; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D001283:Atrioventricular Node / Q000503:physiopathology*; D002304:Cardiac Pacing, Artificial / Q000009:adverse effects*; D009202:Cardiomyopathies / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D006801:Humans; D008297:Male; D008875:Middle Aged; D012804:Sick Sinus Syndrome / Q000150:complications / Q000503:physiopathology / Q000628:therapy*; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000188:drug therapy / Q000209:etiology* / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D000889:Anti-Arrhythmia Agents; D000638:Amiodarone
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