Native T1 mapping identifies subclinical left ventricular myocardial t1 abnormality in patients with atrial fibrillation referred for pulmonary vein isolation
© Kato et al; licensee BioMed Central Ltd. 2015
Published: 3 February 2015
Native T1 mapping has emerged as a noninvasive magnetic resonance imaging (MRI) method to assess the diffuse myocardial fibrosis without an exogenous contrast agents. To date, no data are available regarding native left ventricular (LV) T1 relaxation time in AF patients referred for pulmonary vein isolation (PVI). The purpose of this study was to compare native myocardial T1 value between AF patients undergoing PVI and control subjects.
Thirty one AF patients referred for PVI (58±8 yrs; 23 m) and 17 control subjects (50±15 yrs; 13 m) were retrospectively identified. All patients were in sinus rhythm during the CMR scan. No AF patient had a history of myocardial infarction but 7 of 31 (23%) AF patients had history of hypertension. Non-contrast T1 mapping images were acquired using a Modified Look-Locker imaging sequence (MOLLI) in 3 short-axis planes (basal, mid and apical slices) using an ECG-triggered single-shot acquisition with a balanced SSFP readout (TR 3.1; TE 1.5; FA 35°; FOV 360×337 mm2; acquisition matrix 188×135; voxel size 1.9 × 2.5 mm2; slice thickness 8 mm). Late gadolinium enhanced (LGE) MRI was acquired to evaluate for myocardial scar.
LV ejection fraction was similar between groups (AF: 60±7%, controls: 58±7%, p=0.27). No LGE myocardial scar was observed in any AF patient or control subject. Myocardial native T1 was significantly elevated in AF patients (1106±48 msec vs 1059±33 msec, p=0.001). Multivariate linear regression analysis selected presence of AF as an independent and significant predictor of elevated native T1 after adjustment for age and gender (OR: 25.8, 95%CI: 2.9 - 228.3, p=0.003).
Our study suggests that there are subclinical differences (vs. normal controls) in native myocardial T1 between AF patients referred for PVI. These data suggests that T1 mapping may be useful for early detection of subclinical LV myocardial abnormalities in the AF population.
This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.