title: Radiofrequency catheter ablation for intra-atrial reentrant tachycardia after surgery of atrial septal defect: use of isopotential mapping (QMS system) to demonstrate bidirectional complete block.
abstract: A 51 year-old Japanese man who had undergone surgical correction of an atrial septal defect at the age of 18 years old was referred to our institute for evaluation of his atrial arrhythmia. The conventional electrophysiological study was combined with a new technique utilizing an isopotential and isochronal mapping system (QMS) to visualize the electrical signals recorded with a 64-electrode basket catheter. Using this system, an intra-atrial reentrant tachycardia (IART) was demonstrated. The isopotential map recorded with the QMS (QMS-isoP) rapidly revealed a clockwise global reentrant circuit in the mid free wall of the right atrium and a narrowest activation isthmus between the lower end of the atriotomy scar and the inferior vena cava (IVC). After confirming entrainment with concealed fusion at the lower end of the atriotomy scar, radiofrequency energy was delivered linearly from this site to the IVC by slowly dragging the catheter. The elimination of the IART was defined by the QMS-isoP which demonstrated bidirectional block during pacing from both sides of the ablated linear lesion. The conventional technique of entrainment with concealed fusion combined with the QMS-isoP may result in a highly sophisticated method for identifying global reentrant circuits and for defining bidirectional block after eliminating the IART.
authors.affiliation: Department of Clinical Laboratory Medicine, Matsusaka City Hospital, Tonomachi 1550, Matsusaka, Mie 515-8544, Japan. fumiya@sirius.ocn.ne.jp
authors.forename: Fumiya
authors.initials: F
authors.lastname: Uchida
authors.forename: Atsunobu
authors.initials: A
authors.lastname: Kasai
authors.forename: Eitaro
authors.initials: E
authors.lastname: Fujii
authors.forename: Koji
authors.initials: K
authors.lastname: Matsuoka
authors.forename: Setsuya
authors.initials: S
authors.lastname: Okubo
authors.forename: Shinobu
authors.initials: S
authors.lastname: Teramura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakano
mesh_terms: D018780:Body Surface Potential Mapping; D017115:Catheter Ablation / Q000379:methods*; D004594:Electrophysiology; D005500:Follow-Up Studies; D006327:Heart Block / Q000175:diagnosis / Q000209:etiology / Q000601:surgery*; D006344:Heart Septal Defects, Atrial / Q000150:complications* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012720:Severity of Illness Index; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery*; D016896:Treatment Outcome