Abstract 14970: Cardiac T1 Mapping for Assessment of Biventricular Structural Remodeling in a Canine Model of Atrial Fibrillation
Background: Left atrial structural remodeling is a key feature in atrial fibrillation (AF) pathophysiology. The relationship between AF and ventricular structural remodeling is less known. We sought to investigate biventricular structural remodeling in an established canine model with chronic AF (> 20 months).
Methods: 14 mongrel dogs were implanted with a pacemaker (PM) to induce chronic AF via rapid atrial pacing (RAP). Animals were imaged with a 3T MRI system (Siemens; Verio) at baseline and 2-20 months (2-3 month steps) after AF was induced. MRI protocol included cardiac cine MRI and arrhythmia-insensitive rapid cardiac T1 mapping (15 min after administration of 0.15 mmol/kg of Gd-BOPTA) methods. The disease progression was analyzed by associations (linear mixed effect) between cardiac T1 and RAP duration and between cardiac functional measurements and RAP duration.
Results: Figure 1 shows representative cardiac T1 maps and cine MR images in three short-axis planes of a dog at 464 days after the onset of RAP. As summarized in Table 1, only left ventricular (LV) and right ventricular (RV) ejection fraction (EF), RV end-systolic volume, and LV and RV T1 times were significantly correlated with RAP (or disease) duration (p <0.05).
Conclusions: While both EF and T1 measurements correlated with ventricular remodeling, cardiac T1 measurement has the potential advantage of identifying reversible remodeling over EF measurement. This potential advantage needs to be validated in a study aimed at evaluating the predictive value of EF and T1 measurements with respect to functional ventricular improvement following AF treatment such as RF ablation.
- © 2013 by American Heart Association, Inc.