title: Cardiac magnetic resonance imaging assessment of regional and global left atrial function before and after catheter ablation for atrial fibrillation.
abstract: BACKGROUND
  Ablation of the left atrium and pulmonary veins antrum (PVAI) can be an effective treatment of atrial fibrillation (AF). However, there is discrepancy in the literature regarding the effect extensive ablation has on left atrial (LA) function. We sought to evaluate the effect that AF ablation procedures has on global and regional wall motion as assessed by cardiovascular magnetic resonance imaging (MRI).
  
  
  METHODS
  Consecutive patients undergoing PVAI had cardiac MRI performed preablation and 3 months post ablation. Patients included paroxysmal (n = 16) and persistent/permanent (n = 13). In addition, 12 volunteers underwent cardiac MRI to provide a control population. LA transport function was assessed by obtaining cyclical change indices, total percent emptying, LA stroke volume indices, and LA active percent emptying. Using chordal segment analysis and radial motion of the left atrium, regional motion was assessed throughout the LA emptying cycle.
  
  
  RESULTS
  All four PVs were isolated for all patients. Imaging revealed a significant reduction in LA volumes in AF patients post-PVAI. In the subset of patients with persistent AF, post-PVAI improvements were seen in global (p < 0.01) and regional LA functions (p = 0.01). In the paroxysmal AF patients, post-PVAI measurements revealed decreases in LA transport function (p = 0.02) as well as diminished regional function in the LA lateral wall (p = 0.02). The paroxysmal AF patients had global and regional LA functions comparable to the normal volunteers prior to ablation; however, these were significantly diminished post ablation.
  
  
  CONCLUSIONS
  Extensive ablation during PVAI causes mild deterioration in LA function. However, in patients with a high burden of AF, it appears that the positive remodeling that occurs with rhythm restoration outweighs any negative effects of ablation.
authors.affiliation: Department of Cardiovascular Medicine, Beaumont Hospital, 3601 West Thirteen Mile Road, Royal Oak, MI, 48073, USA.
authors.forename: David
authors.initials: D
authors.lastname: Nori
authors.forename: Gilbert
authors.initials: G
authors.lastname: Raff
authors.forename: Vikesh
authors.initials: V
authors.lastname: Gupta
authors.forename: Ralph
authors.initials: R
authors.lastname: Gentry
authors.forename: Judith
authors.initials: J
authors.lastname: Boura
authors.forename: David E
authors.initials: DE
authors.lastname: Haines
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D016275:Atrial Function; D017115:Catheter Ablation / Q000009:adverse effects*; D005260:Female; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology*