Abstract 18707: The Baseline Image Intensity Ratio, a Surrogate for Pre-existing Left Atrial Fibrosis, is Associated With Recurrence of Atrial Fibrillation Following Pulmonary Vein Isolation
Introduction: Catheter ablation of AF is beneficial for many patients, but it is associated with a high AF recurrence rate that previously has been correlated with left atrial (LA) fibrosis on late gadolinium enhanced (LGE) MRI. We sought to test the association of LA fibrosis with recurrent post-ablation AF, using the image intensity ratio (IIR), a novel and standardized measure for quantification and inter-patient comparisons of LA fibrosis.
Methods: Fifty consecutive AF patients (59.2±9.0 years, 74% men, 44% persistent AF) were enrolled and underwent LGE-MRI prior to initial AF ablation procedure. The local IIR was defined as the LA myocardial signal intensity of each sector in axial plane divided by the mean LA blood pool image intensity. The cohort was divided into four groups using mean IIR thresholds of 0.95. The mean follow-up was 9.0±4.6 months, and recurrences were documented with routine follow-up and symptom-prompted electrocardiography as well as phone calls.
Results: Of 50 total patients, 11 (22%) experienced AF recurrence (4/28 paroxysmal AF (14.3%), and 7/ 22 persistent AF (31.8%)). The baseline IIR was higher in paroxysmal AF patients that experienced recurrence (1.0±0.18 vs. 0.81±0.08, p=0.001), but was similar in persistent AF patients with or without recurrence (0.84±0.12 vs. 0.88±0.14, p=NS). The Figure illustrates Kaplan-Meier survival analyses based upon baseline IIR derived patient groups.
Conclusions: Baseline left atrial fibrosis is strongly associated with AF recurrence in patients with paroxysmal AF, but is unassociated with outcomes in patients with persistent AF.
- © 2013 by American Heart Association, Inc.