Abstract 18458: Cardiac Magnetic Resonance T1 Mapping Identifies Diffuse Ventricular Fibrosis in Patients With Atrial Fibrillation Undergoing First and Repeat Catheter Ablation
Background: Left ventricular (LV) T1 mapping by cardiac magnetic resonance (CMR) imaging may quantitatively identify diffuse LV fibrosis in patients with atrial fibrillation (AF). An inverse relationship between T1 relaxation times after gadolinium and degree of LV fibrosis is hypothesized. The primary aim of this study was to compare LV T1 times amongst healthy volunteers, patients undergoing first time catheter ablation for AF, and patients undergoing repeat ablation for recurrent AF.
Methods: CMR imaging at 1.5-Tesla was performed in patients with symptomatic AF before ablation and in healthy volunteers. A modified Look-Locker inversion-recovery (MOLLI) sequence (11 images within 17 heartbeats) was acquired in the vertical long axis plane 12 min after gadolinium chelate (0.20 mmol/kg). T1 measurements were obtained from the inferoposterior LV myocardial wall.
Results: 51 patients (64% males, median age 55 years, inter-quartile range [IQR] 51-65 years) (53% prior to first ablation, 47% prior to repeat ablation) and in 16 healthy volunteers (31% males, median age 26 years, IQR 23-30 years) were evaluated. The median LV T1 relaxation time was lower in patients with AF undergoing first ablation (454ms, IQR 412-474ms) and recurrent ablation (431ms, IQR 412-464ms) compared to healthy volunteers (595ms, IQR 566-606ms, P<0.001) [Figure]. In an ordered logistic regression model, T1 time remained associated (p=0.044) with participant status (control, prior to first ablation, prior to repeat ablation) as the dependent variable, after adjusting for age, gender, BMI, and DM.
Conclusion: Post-gadolinium ventricular T1 mapping identifies diffuse LV fibrosis in AF patients undergoing first and repeat catheter ablation. Lower T1 times were observed in patients who had prior ablation attempts, suggesting greater LV fibrosis in those with recurrent AF. Further studies will be needed to determine changes in T1 time after restoration of sinus rhythm with catheter ablation.
- © 2013 by American Heart Association, Inc.