title: Electrocardiographic and electrophysiologic characteristics of anteroseptal, midseptal, and para-Hisian accessory pathways. Implication for radiofrequency catheter ablation.
abstract: OBJECTIVE
  To investigate the ECG characteristics, the electrophysiologic properties, and an effective radiofrequency catheter ablation technique in patients with septal accessory pathways.
  
  
  METHODS
  Forty-six consecutive subjects with septal accessory pathways located in the anteroseptal, midseptal, and para-Hisian areas.
  
  
  METHODS
  ECGs obtained during sinus rhythm and orthodromic tachycardia, conduction properties obtained from electrophysiologic study, and results of two different ablation techniques were analyzed.
  
  
  RESULTS
  (1) Twenty-four (52.2%) had manifest preexcitation and 15 (32.6%) had multiple accessory pathways; (2) midseptal pathways could be differentiated from anteroseptal and para-Hisian pathways by a negative delta wave in lead III and a biphasic delta wave in lead aVF during sinus rhythm, and a negative retrograde P wave in two inferior leads during orthodromic tachycardia; (2) midseptal pathways had better antegrade conduction properties and a significantly higher incidence (61.5%) of inducible atrial fibrillation; (4) radiofrequency catheter ablation using lower energy (20+/-6 W) had a comparable effect to ablation using higher energy (36+/-5 W), but without impairment of atrioventricular (AV) node conduction or development of AV block; and (5) during the follow-up period of 26+/-14 months (range, 5 to 54 months), three (6.5%) patients had recurrence.
  
  
  CONCLUSIONS
  Midseptal accessory pathways had ECG and electrophysiologic characteristics that were distinctive from those of anteroseptal and para-Hisian pathways. Catheter ablation of these septal pathways using low radiofrequency energy was safe and effective.
authors.affiliation: Division of Cardiology, Department of Medicine, National Yang-Ming University, School of Medicine, Taipei, Taiwan, Republic of China.
authors.forename: C T
authors.initials: CT
authors.lastname: Tai
authors.forename: S A
authors.initials: SA
authors.lastname: Chen
authors.forename: C E
authors.initials: CE
authors.lastname: Chiang
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: M S
authors.initials: MS
authors.lastname: Chang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017115:Catheter Ablation; D004562:Electrocardiography; D004594:Electrophysiology; D005260:Female; D006329:Heart Conduction System / Q000002:abnormalities* / Q000502:physiology / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged