Morphologic remodeling of pulmonary veins and left atrium after catheter ablation of atrial fibrillation: insight from long-term follow-up of three-dimensional magnetic resonance imaging.
BACKGROUND
Understanding the structural remodeling and reverse remodeling of the left atrium (LA) and pulmonary vein (PV) after radiofrequency ablation of atrial fibrillation (AF) may provide important insights into the mechanism and management of AF. This study used magnetic resonance angiographic (MRA) images to investigate changes in PV and LA morphologies before and more than 1 year after ablation.


RESULTS
Forty-five patients (36 men and 9 women, mean age 60 +/- 13 years) who underwent MRA before and more than 12 months (mean 21 +/- 11) after ablation of paroxysmal AF were included in the study. The patients were divided into two groups: group I included 35 patients without AF recurrence, and group II included 10 patients with late (>1 month postablation) recurrence of AF. The sizes of the LA and nonablated PV were compared before and after ablation. In group I, significant reduction of ostial area of both superior PVs was noted (left superior PV: from 2.85 +/- 0.67 to 2.59 +/- 0.73 cm2; right superior PV: from 2.89 +/- 0.85 to 2.60 +/- 0.73 cm2, both P <0.001). Geometric alteration toward a round shape was noted in the ostia of superior PVs during follow-up (eccentricity of right superior PV and left superior PV decreased from 0.31 +/- 0.10 to 0.22 +/- 0.13 and from 0.27 +/- 0.11 to 0.19 +/- 0.13, respectively, both P <0.01). However, LA volume showed only borderline reduction (from 61.52 +/- 19.06 to 56.64 +/- 17.13 mL, P=0.05). In group II, significant dilation of the LA (from 61.14 +/- 17.54 to 78.73 +/- 25.27 mL, P=0.004) and right superior PV (from 3.41 +/- 1.12 to 4.08 +/- 1.31 cm2, P=0.016) was noted during follow-up. Ostial area and eccentricity of the left superior, left inferior, and right inferior PVs and LA were similar before and after ablation.


CONCLUSIONS
Structural remodeling of the superior PVs and LA can be reversible after successful ablation without AF recurrence; however, late recurrence of AF is associated with progressive LA dilation.
Tsao
Hsuan-Ming
HM
Division of Cardiology, Department of Medicine, National Yang-Mind University, School of Medicine, and Taipei Veterans Hospital, Taiwan.
Wu
Mei-Han
MH
Huang
Bien-Hsien
BH
Lee
Shih-Huang
SH
Lee
Kun-Tai
KT
Tai
Ching-Tai
CT
Lin
Yung-Kuo
YK
Hsieh
Ming-Hsiung
MH
Kuo
Jen-Yuan
JY
Lei
Meng-Huan
MH
Chen
Shih-Ann
SA
D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000601:surgery*; D017115:Catheter Ablation / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006325:Heart Atria / Q000473:pathology*; D006801:Humans; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011667:Pulmonary Veins / Q000473:pathology*; D012008:Recurrence; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D013223:Statistics as Topic; D016896:Treatment Outcome