title: Thoracic vein ablation terminates chronic atrial fibrillation in dogs.
abstract: The thoracic vein hypothesis of chronic atrial fibrillation (AF) posits that rapid, repetitive activations from muscle sleeves within thoracic veins underlie the mechanism of sustained AF. If this is so, thoracic vein ablation should terminate sustained AF and prevent its reinduction. Six female mongrel dogs underwent chronic pulmonary vein (PV) pacing at 20 Hz to induce sustained (>48 h) AF. Bipolar electrodes were used to record from the atria and thoracic veins, including the vein of Marshall, four PVs, and the superior vena cava. Radio frequency (RF) application was applied around the PVs and superior vena cava and along the vein of Marshall until electrical activity was eliminated. Computerized mapping (1,792 electrodes, 1 mm resolution) was also performed. Sustained AF was induced in 30.6 +/- 6.5 days, and ablation was done 17.3 +/- 8.5 days afterward. Before ablation, the PVs had shorter activation cycle lengths than the atria, and rapid, repetitive activations were observed in the PVs. All dogs converted to sinus rhythm during (n = 4 dogs) or within 90 min of completion of RF ablation. Rapid atrial pacing afterward induced only nonsustained (<60 s) AF in all dogs. Average AF cycle lengths after reinduction were significantly (P = 0.01) longer (183 +/- 31.5 ms) than baseline (106 +/- 16.2 ms). There were no activation cycle length gradients after RF application. We conclude that thoracic vein ablation converts canine sustained AF into sinus rhythm and prevents the reinduction of sustained AF. These findings suggest that thoracic veins are important in the maintenance of AF in dogs.
authors.affiliation: Division of Cardiology, Rm. 5342, Cedars-Sinai Medical Center, 8700 Beverly Blvd., Los Angeles, CA 90048-1865, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Park
authors.forename: Chung-Chuan
authors.initials: CC
authors.lastname: Chou
authors.forename: Paul C
authors.initials: PC
authors.lastname: Drury
authors.forename: Yuji
authors.initials: Y
authors.lastname: Okuyama
authors.forename: Anish
authors.initials: A
authors.lastname: Peter
authors.forename: Akira
authors.initials: A
authors.lastname: Hamabe
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Miyauchi
authors.forename: Robert M
authors.initials: RM
authors.lastname: Kass
authors.forename: Hrayr S
authors.initials: HS
authors.lastname: Karagueuzian
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: Shien-Fong
authors.initials: SF
authors.lastname: Lin
authors.forename: Peng-Sheng
authors.initials: PS
authors.lastname: Chen
mesh_terms: D000818:Animals; D001281:Atrial Fibrillation / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery*; D017115:Catheter Ablation; D002908:Chronic Disease; D004285:Dogs; D004558:Electric Stimulation; D004566:Electrodes; D005260:Female; D009206:Myocardium / Q000473:pathology; D010138:Pacemaker, Artificial; D011667:Pulmonary Veins / Q000502:physiology / Q000601:surgery*; D014683:Vena Cava, Superior / Q000502:physiology