title: Percutaneous ligation of the left atrial appendage results in atrial electrical substrate modification.
abstract: Debulking of electrically active atrial tissue may reduce the mass of fibrillating tissue during atrial fibrillation, eliminate triggers, and promote maintenance of normal sinus rhythm (NSR). We investigated whether left atrial appendage (LAA) ligation results in modification of atrial electrical substrate. Healthy male mongrel dogs (N = 20) underwent percutaneous epicardial LAA ligation. The ligation system grabber recorded LAA local electrograms (EGM) continuously before, during, and after closure. Successful ligation with a preloaded looped suture was confirmed intraprocedurally by LAA Doppler flow cessation on transesophageal echocardiography (TEE) and loss of LAA electrical activity, and after procedure by direct necropsic visualization. P-wave duration on surface electrocardiograms was measured immediately before and after LAA closure. Percent P-wave duration reduction was correlated with preclosure LAA internal dimensions measured by TEE and external dimensions measured on necropsy specimens to investigate associations of LAA geometry with the extent of electrical substrate modification. LAA ligation was successful in all dogs and accompanied by loss of LAA EGM. P-wave duration reduced immediately on ligation (mean 75 ms preligation to 63 ms postligation; mean difference ± standard error, 12 ± 1 ms; P < 0.0001). Percent P-wave reduction was associated with larger LAA longitudinal cross-sectional area (R(2) = 0.263, P = 0.04) and smaller external circumference (R(2) = 0.687, P = 0.04). All dogs were in sinus rhythm. Percutaneous LAA ligation results in its acute electrical isolation and atrial electrical substrate modification, the degree of which is associated with LAA geometry. These electrical changes raise the possibility that LAA ligation may promote NSR by removing LAA substrate and triggers.
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minn.
authors.forename: Faisal F
authors.initials: FF
authors.lastname: Syed
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minn.
authors.forename: Venu
authors.initials: V
authors.lastname: Rangu
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minn.
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Bruce
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minn.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Johnson
authors.affiliation: Mayo Clinic Health Solutions, Mayo Clinic, Rochester, Minn.
authors.forename: Andrew
authors.initials: A
authors.lastname: Danielsen
authors.affiliation: Mayo Clinic Health Solutions, Mayo Clinic, Rochester, Minn.
authors.forename: Emily J
authors.initials: EJ
authors.lastname: Gilles
authors.affiliation: Mayo Clinic Health Solutions, Mayo Clinic, Rochester, Minn.
authors.forename: Dorothy J
authors.initials: DJ
authors.lastname: Ladewig
authors.affiliation: Mayo Clinic Health Solutions, Mayo Clinic, Rochester, Minn.
authors.forename: Susan B
authors.initials: SB
authors.lastname: Mikell
authors.affiliation: Access Point Technologies, Rogers, Minn.
authors.forename: Steven
authors.initials: S
authors.lastname: Berhow
authors.affiliation: Access Point Technologies, Rogers, Minn.
authors.forename: Douglas
authors.initials: D
authors.lastname: Wahnschaffe
authors.affiliation: Department of Surgical Research, Mayo Clinic, Rochester, Minn.
authors.forename: Scott H
authors.initials: SH
authors.lastname: Suddendorf
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minn; Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, Minn.
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Asirvatham
authors.affiliation: Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minn. Electronic address: friedman.paul@mayo.edu.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
mesh_terms: D000818:Animals; D020517:Atrial Appendage / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D004285:Dogs; D004562:Electrocardiography; D055724:Electrophysiological Phenomena; D008026:Ligation; D008297:Male; D014463:Ultrasonography