title: Inducible atrioventricular nodal reentrant echo behind organic 2:1 infra-hisian block during sinus rhythm.
abstract: A 77-year-old male patient with an intermittent 2:1 infra-Hisian block during sinus rhythm was presented with dizziness and near-syncope. During electrophysiological (EP) study, dual atrioventricular (AV) nodal pathways and retrograde fast pathway were easily induced by atrial and ventricular programmed stimulation, respectively. A typical slow-fast AV nodal reentrant echo beat also could be demonstrated by single atrial extrastimulation. Atrioventricular nodal reentrant tachycardia (AVNRT) can occasionally exhibit 2:1 AV block. Conversely, AV nodal reentry property had been rarely reported behind 2:1 infra-Hisian block. The EP presentation from this case may support the notion that tissues below the His are not part of the reentrant circuit of AVNRT.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Kaohsiung Medical University Chung-Ho Memorial Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, Republic of China.
authors.forename: Chih-Sheng
authors.initials: CS
authors.lastname: Chu
authors.forename: Kun-Tai
authors.initials: KT
authors.lastname: Lee
authors.forename: Wen-Ter
authors.initials: WT
authors.lastname: Lai
mesh_terms: D000368:Aged; D004562:Electrocardiography; D006327:Heart Block / Q000175:diagnosis* / Q000209:etiology*; D006801:Humans; D008297:Male; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000175:diagnosis*