Diffuse Ventricular Fibrosis Measured by T1 Mapping on Cardiac MRI Predicts Success of Catheter Ablation for Atrial Fibrillation
Background—There is a complex interplay between the atria and ventricles in AF. Cardiac magnetic resonance (CMR) imaging provides detailed tissue characterisation, identifying focal ventricular fibrosis with late gadolinium enhancement (ventricular LGE) and diffuse fibrosis with post-contrast enhanced T1 mapping. The aim of the present study was to investigate the relationship between post-contrast ventricular T1 relaxation time on CMR and freedom from atrial fibrillation (AF) following pulmonary vein isolation (PVI).
Methods and Results—103 patients undergoing catheter ablation for symptomatic AF (66% paroxysmal AF; age 58±10 years; LA area 27±7cm2) underwent preprocedure CMR to determine post-contrast ventricular T1 time. Follow up included clinical review and 7 Day Holter monitors at 6 monthly intervals. All patients underwent successful PVI. At a mean follow up of 15±7 months, the single procedure success was 74%. Post-contrast ventricular T1 time was significantly shorter in patients with recurrent AF (366±73ms) vs patients without AF recurrence (428±90ms; p=0.002). Univariate predictors of AF recurrence included post-contrast ventricular T1 time, AF type (paroxysmal vs. persistent), AF duration, and BMI. Following multivariate analysis ventricular T1 time (p=0.03) and AF duration (p=0.03) were the only independent predictors. Freedom from AF was present in 84% of patients with a post-contrast ventricular T1 time >380ms vs. 56% in patients with a post-contrast ventricular T1 time<380ms (p=0.002).
Conclusions—A shorter post-contrast ventricular T1 relaxation time on CMR is associated with reduced freedom from AF post catheter ablation. Diffuse ventricular fibrosis as demonstrated by CMR may in part explain recurrent AF following AF ablation.
- Received January 20, 2014.
- Revision received July 14, 2014.
- Accepted July 22, 2014.