title: Accessory atrioventricular pathway at the antero-medial mitral annulus--electrophysiologic characteristics and radiofrequency catheter ablation: a case report.
abstract: Accessory atrioventricular (AV) pathway located at or near the region of aorta-mitral continuity has rarely been mentioned. This report describes one such case with a concealed accessory AV pathway at the anteromedial mitral annulus adjacent to aorta-mitral continuity. The location of the accessory pathway was confirmed by successful radiofrequency catheter ablation. This patient was a 26-year-old male. His 12-lead surface ECG showed no evidence of ventricular preexcitation during sinus rhythm. The earliest retrograde atrial depolarization recorded from the routine catheters was at the His bundle area during ventricular pacing and orthrodromic AV reentrant tachycardia; paradoxically, the earliest left-sided atrial activation recorded from the coronary sinus catheters was at the distal coronary sinus area. The unique retrograde atrial activation sequence over the left atrium and His bundle area was not true for patients with left lateral or anterolateral accessory pathway. During tachycardia, the local electrogram from the successful ablation site showed local VA fusion in the anteromedial mitral annulus. After delivering one pulse of radiofrequency energy (30W), the accessory AV pathway was successfully eliminated without complication. This report presents a concealed left-sided accessory AV pathway at an unusual location. It is very important to describe special electrophysiologic characteristics and ablation technique in this unusual accessory pathway to improve knowledge in the era of interventional electrophysiology.
authors.affiliation: Division of Cardiology, Department of Medicine, National Yang-Ming University School of Medicine; and Veterans General Hospital-Taipei, Taiwan, R.O.C.
authors.forename: T J
authors.initials: TJ
authors.lastname: Wu
authors.forename: S A
authors.initials: SA
authors.lastname: Chen
authors.forename: C T
authors.initials: CT
authors.lastname: Tai
authors.forename: C E
authors.initials: CE
authors.lastname: Chiang
authors.forename: S H
authors.initials: SH
authors.lastname: Lee
authors.forename: C C
authors.initials: CC
authors.lastname: Cheng
authors.forename: S P
authors.initials: SP
authors.lastname: Wang
authors.forename: B N
authors.initials: BN
authors.lastname: Chiang
authors.forename: M S
authors.initials: MS
authors.lastname: Chang
mesh_terms: D000328:Adult; D001283:Atrioventricular Node / Q000503:physiopathology; D017115:Catheter Ablation; D006801:Humans; D008297:Male; D011226:Pre-Excitation Syndromes / Q000503:physiopathology* / Q000601:surgery