Abstract 14960: Left Ventricular Native T1 Time and the Risk of Arial fibrillation Recurrence After Pulmonary Vein Isolation in Patients With Paroxysmal Atrial Fibrillation

Abstract

Introduction: Native T1 mapping has emerged as a noninvasive non-contrast magnetic resonance imaging (MRI) method to assess for diffuse myocardial fibrosis. However, LV native T1 time in atrial fibrillation (AF) patients and its clinical relevance are unclear. Hypothesis: We hypothesized that native T1 time is elevated in AF patients and elevated native T1 time is associated with higher rate of AF recurrence after pulmonary vein isolation (PVI). Methods: Fifty paroxysmal AF patients referred for PVI (60±8 years, 37 male) and 13 healthy control subjects (57±8 years, 10 male) were studied. All patients were in sinus rhythm during the MRI scan. Native T1 mapping images were acquired using a Modified Look-Locker imaging (MOLLI) sequence in 3 short-axis planes (basal, mid and apical slices) using an electrocardiogram triggered single-shot acquisition with a balanced steady-state free precession readout. Results: LV ejection fraction was similar between groups (AF: 61±6%; controls: 60±5%, p=0.31). No LV myocardial scar was observed in any patient on LGE. Myocardial native T1 time was greater in AF patients (1099±52 vs 1047±26 msec, p=0.001). During a mean follow-up period of 233 days, 7 of 50 (14%) patients experienced recurrence of AF. Kaplan Meier curve demonstrated significant difference in AF recurrence between patients with elevated LV native T1 time and patients with non-elevated LV native T1 time (p=0.032 by Log-rank test, elevated native LV T1 time was defined as >2SD of controls: 1099msec). Cox proportional hazard analysis identified native T1 time as an independent predictor of recurrence of AF (HR: 1.21, 95% CI: 1.05-1.40, p=0.009). Conclusions: There are differences in the native LV myocardial T1 time between AF patients with preserved LV function referred for PVI and normal controls. Native T1 time is an independent predictor of recurrence of AF after PVI in patients with paroxysmal AF.