title: Electrocardiographic identification of mid-septal accessory pathways in close proximity to the atrioventricular conduction system.
abstract: In order to identify ECG characteristics of overt mid-septal accessory pathways (APs) predictive of close proximity to the AV conduction system we analyzed data from patients who underwent successful RF catheter ablation of a mid-septal AP. Mean patient age was 31 +/- 16 years, and 13 were male. The 40 degrees right anterior oblique view was used to divide the mid-septal area into 3 zones: 1 (anterior portion); 2 (intermediate); and 3 (posterior portion). The 12-lead ECG was analyzed with regard to delta wave polarity and R/S transition in the precordial leads. The findings from patients ablated at zone 3 were compared to those at zones 1 and 2. All patients had a positive delta wave in the leads I, II, aVL, and negative delta wave in the leads III and aVR. The R/S transition occurred in lead V2 in 80% of patients. The delta wave in lead aVF was the only ECG characteristic that correlated with the AP ablation zone. Six of 8 patients ablated at zone 3 had a negative delta wave in lead aVF while 6 out of 7 patients ablated at zone 1 or 2 had a positive or isoelectric delta wave in lead aVF (P = 0.03). A positive or isoelectric delta wave in lead aVF identifies mid-septal AP in close proximity to the AV conduction system.
authors.affiliation: Heart Institute, São Paulo, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Lorga Filho
authors.forename: E
authors.initials: E
authors.lastname: Sosa
authors.forename: M
authors.initials: M
authors.lastname: Scanavacca
authors.forename: A
authors.initials: A
authors.lastname: d'Avila
authors.forename: R
authors.initials: R
authors.lastname: Kuniyoshi
authors.forename: J
authors.initials: J
authors.lastname: de Horta
authors.forename: G
authors.initials: G
authors.lastname: Fenelon
authors.forename: P
authors.initials: P
authors.lastname: Brugada
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001283:Atrioventricular Node / Q000473:pathology*; D017115:Catheter Ablation; D002648:Child; D004562:Electrocardiography / Q000145:classification / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006329:Heart Conduction System / Q000473:pathology* / Q000601:surgery; D006346:Heart Septum / Q000294:innervation*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012086:Reoperation; D013617:Tachycardia, Supraventricular / Q000473:pathology / Q000601:surgery