title: Regional left atrial interstitial remodeling in patients with chronic atrial fibrillation undergoing mitral-valve surgery.
abstract: Ablation of the left atrial free wall around the pulmonary vein ostia (LAFW) may be effective in the treatment of chronic atrial fibrillation associated with mitral disease (CAF-MVD). Using light and conventional electron microscopy analyses, we wanted to evaluate, in CAF-MVD, the interstitial remodeling in the LAFW as well as in a more remote region, such as the left atrial appendage (LAA). LAFW and LAA samples were obtained from 33 CAF-MVD patients during combined mitral surgery and radiofrequency ablation and from 16 autoptic controls. Interstitial fibrosis (IF) and perivascular fibrosis (PF), capillary densities and the maximal oxygen diffusion distance were morphometrically determined. In CAF-MVD patients, the LAFW, compared with the LAA, showed a higher percentage of IF (7.16+/-3.23% versus 2.51+/-1.40%, respectively), a lower myocardial capillary density per mm(2) (830+/-106 versus 989+/-173) and an increased oxygen maximal diffusion distance (19.70+/-1.27 microm versus 18.13+/-1.58 microm). All these values were also significantly different than controls. No differences were found in evaluating PF. At variance with the LAA, in CAF-MVD patients, the LAFW around the pulmonary vein ostia is a region characterized by a marked interstitial remodeling such that it may be morphologically indicated as an appropriate target for ablation treatment aimed at sinus rhythm restoration.
authors.affiliation: Department of Pathology and Laboratory Medicine, Pathology Section, University of Parma, Via Gramsci 14, 43100 Parma, Italy. dcorrad8@unipr.it
authors.forename: Domenico
authors.initials: D
authors.lastname: Corradi
authors.forename: Sergio
authors.initials: S
authors.lastname: Callegari
authors.forename: Stefano
authors.initials: S
authors.lastname: Benussi
authors.forename: Simona
authors.initials: S
authors.lastname: Nascimbene
authors.forename: Paolo
authors.initials: P
authors.lastname: Pastori
authors.forename: Simone
authors.initials: S
authors.lastname: Calvi
authors.forename: Roberta
authors.initials: R
authors.lastname: Maestri
authors.forename: Ettore
authors.initials: E
authors.lastname: Astorri
authors.forename: Carlo
authors.initials: C
authors.lastname: Pappone
authors.forename: Ottavio
authors.initials: O
authors.lastname: Alfieri
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020517:Atrial Appendage / Q000503:physiopathology*; D001281:Atrial Fibrillation / Q000503:physiopathology* / Q000601:surgery; D002908:Chronic Disease; D005260:Female; D006349:Heart Valve Diseases / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000601:surgery*; D009206:Myocardium / Q000648:ultrastructure