title: Long-term outcome of twin atrioventricular node and supraventricular tachycardia in patients with right isomerism of the atrial appendage.
abstract: BACKGROUND
  Twin AV nodes and resulting supraventricular tachycardia (SVT) have been described in right atrial isomerism (RAI).
  
  
  OBJECTIVE
  We sought to analyze the long-term outcome of patients with RAI with a focus on rhythm disturbances.
  
  
  METHODS
  Retrospective study of 257 patients (152 male and 105 female, 1,171 patient-years) with RAI diagnosed between 1980 and 2005.
  
  
  RESULTS
  SVT in 68 patients (26%) occurred at various ages from the prenatal period to 15 years and was only significantly associated with balanced ventricles (P = .009). Cardioversion was achieved in by verapamil in 6 of 6 cases (100%), adenosine in 18 of 21 cases (88%) and propranolol in 10 of 12 cases (83%). Electrocardiographic evidence of twin AV nodes, as shown by 2 discrete non-pre-excited QRS complexes, was found in 28 of 44 (64%) patients with more than 2 electrocardiograms, and was more frequent in those with balanced ventricles rather than a dominant ventricle and would increase risk of SVT. Recurrence of SVT was documented in 27 (40%) patients 1 day to 4.5 years after the first episode. However, the occurrence or recurrence of SVT was not associated with increased all-cause or surgical mortality or sudden death. Successful catheter ablation of ventriculoatrial pathways with junctional ectopic tachycardia at radiofrequency energy delivery was obtained in 5 of 6 patients.
  
  
  CONCLUSIONS
  This study showed that twin AV nodes in RAI patients could be disclosed by serial electrocardiograms and that SVT, most likely a twin node tachycardia, was common and tended to recur but could be managed by ablation or medication.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan. wumh@ntu.edu.tw
authors.forename: Mei-Hwan
authors.initials: MH
authors.lastname: Wu
authors.forename: Jou-Kou
authors.initials: JK
authors.lastname: Wang
authors.forename: Jiunn-Lee
authors.initials: JL
authors.lastname: Lin
authors.forename: Ming-Tai
authors.initials: MT
authors.lastname: Lin
authors.forename: Sheun-Nan
authors.initials: SN
authors.lastname: Chiu
authors.forename: Chun-An
authors.initials: CA
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D020517:Atrial Appendage / Q000002:abnormalities / Q000503:physiopathology*; D001283:Atrioventricular Node / Q000002:abnormalities / Q000503:physiopathology*; D017115:Catheter Ablation; D002648:Child; D002675:Child, Preschool; D004554:Electric Countershock; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000002:abnormalities / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D013617:Tachycardia, Supraventricular / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome