Abstract 16497: Atrial Fibrosis Assessed Using Delayed-Enhancement MRI Predicts Sinus Node Dysfunction Requiring Pacemaker Implant
Background: Sinus node dysfunction (SND) commonly manifests with atrial arrhythmias alternating with sinus pauses and sinus bradycardia. The underlying process is thought to be fibrosis surrounding the sinus node. We used Delayed-Enhancement MRI (DE-MRI) to assess the value of atrial fibrosis in predicting significant sinus node dysfunction requiring pacemaker implant.
Methods: 343 patients with atrial fibrillation (AF) presenting for catheter ablation underwent DE-MRI. Left atrial (LA) fibrosis was quantified in all patients and right atrial (RA) fibrosis in 100 patients. All patients underwent catheter ablation with pulmonary vein isolation with posterior wall and septal debulking. Patients were followed prospectively for 329±245 days. Ambulatory monitoring was instituted every 3 months. Symptomatic pauses and bradycardia were treated with pacemaker implantation per published guidelines.
Results: The average patient age was 65±12 years. The average wall fibrosis was 16.7±11.1% in the LA, and 5.3±6.4% in the RA. RA fibrosis was correlated with LA fibrosis (r2=0.18, p<0.01). Pts were divided into 4 stages of LA fibrosis (Utah I: <5%, Utah II: 5–20%, Utah III: 20–35%, Utah IV: >35%). 23 patients (6.8%) required pacemaker implant during follow up. Univariate analysis identified age quartile (OR 1.6) and LA fibrosis stage (OR 2.5) as significant predictors for pacemaker implantation. In multivariate analysis, only atrial fibrosis predicted pacemaker implant (OR 2.3, AUC 0.72).
Conclusions: In patients with AF presenting for catheter ablation, DE-MRI quantification of atrial fibrosis predicts future development of significant SND requiring pacemaker implantation.
- © 2010 by American Heart Association, Inc.