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  • Poster presentation
  • Open Access

Left atrial scar burden determined by delayed enhancement cardiac magnetic resonance at post radiofrequency ablation: association with atrial fibrillation recurrence

  • 1, 2,
  • 2,
  • 2,
  • 2,
  • 1,
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  • 2 and
  • 2
Journal of Cardiovascular Magnetic Resonance201214 (Suppl 1) :P204

https://doi.org/10.1186/1532-429X-14-S1-P204

  • Published:

Keywords

  • Cardiac Magnetic Resonance
  • Left Atrial
  • Atrial Fibrillation Patient
  • Atrial Fibrillation Recurrence
  • Left Ventricle Ejection Fraction

Background

Left atrial (LA) radiofrequency (RF) ablation has become routine treatment for atrial fibrillation (AF) but still suffers from AF recurrence requiring a repeat procedure. LA-RF ablation success rates vary between 53% and 85%. Delayed-enhancement Cardiac Magnetic Resonance (DE-CMR) can be used to noninvasively visualize LA hyperenhancement (scar). We have utilized DE-CMR to quantify LA scar extent post LA-RF-ablation and related this measure to AF recurrence.

Methods

Twenty-seven patients (62.0±11.1 years, 20 males) with paroxysmal and chronic AF underwent LA-RF-ablation and subsequent DE-CMR, an average of 260.7±314.7 days post procedure. The DE-CMR procedure was performed utilizing a navigated 3D inversion recovery gradient echo sequence (Siemens 1.5T Avanto or 3.0T Verio) approximately 15 minutes after administration of 0.2 mmol/kg Diethylenetriaminepentaacetic Acid−Gadolinium (DTPA-Gd, Magnevist, Berlex Laboratories, Wayne, NJ). All scans were electrocardiographically (ECG)-gated and acquired during a 150 ms window in mid-diastole with navigator-gating and fat suppression. We have developed an image analysis method and graphical user interface to semi-automatically quantify hyperenhanced regions in the LA wall (scar). LA scar was quantified by a single experienced observer blinded to patient data. LA-scar measurements were normalized by LA size. The intra-class correlation coefficient (ICC) was used to assess intra-observer variability of 4 randomly selected scans which were re-read one week later. Variables were tested for normality with the Shapiro-Wilk test and a p-value<0.05 was considered statistically significant (all tests were 2-sided). All patients provided informed consent.

Results

The DE-CMR scans were performed 260.7±314.7 days after the initial LA-RF- ablation procedure (Figure). AF recurrence was noted to occur in 13 (48%) patients whereas 14 (52%) patients demonstrated no AF recurrence. There was a trend toward a larger LA-volume in the AF-recurrence group (128.49±44.0 ml vs. 96.0±38.5 ml; p=0.06, see Table 1). Left ventricle ejection fractions (LVEF) were smaller in the AF-recurrence group but the difference was not statistically significant (58.93±12.1% vs. 64.85±6.2.1%, p=0.092). Average analysis time per scan was 14.5±7 min and intra-observer variability was excellent (ICC=0.99). LA-scar was normally distributed (p=0.151). Average LA scar extent, quantified in post LA-RF-ablation DE-CMR scans, was significantly larger in recurrence-free AF patients (16.56±5.3 cm2) when compared with individuals with AF-recurrence (11.40±7.6 cm2; p=0.036). The results indicate that there is a significant inverse relationship between LA-scar burden and AF-recurrence.
Table 1

LA-scar quantification in AF patients.

Variable

AF-Recurrence [N=13, mean, std]

AF-Free [N=14, mean, std]

P-value

LA-Volume [mL]

128.49 ± 44.0

96.0 ± 38.5

0.06

LVEF [%]

58.93 ± 12.1

64.85 ± 6.2.1

0.092

LA-scar [cm2]

11.40 ± 7.6

16.56 ± 5.25

0.036

Age [years]

61.67 ± 9.3

62.23 ± 12.8

0.891

Gender [no. males]

10

10

-

LA= left atrium; LA scar (hyperenhanced area) was normalized by LA volume. N= number of patients; Std=standard deviation; RF= radio frequency; LVEF: left ventricle ejection fraction; AF: atrial fibrillation.

Conclusions

LA scar extent can be reproducibly quantified with DE-CMR; and a lower scar burden post LA-RF-ablation is associated with AF recurrence.

Funding

This work was supported in part by NIH grant T32HL07812.
Figure 1
Figure 1

DE-CMR images of the left atrium (LA) obtained with a Siemens 1.5T Avanto (left and middle panels). The right panel shows the result of the semi-automated LA scar segmentation for the center panel. The left atrium is indicated by the red contour and the blue area highlights hyperenhanced regions (scar).

Authors’ Affiliations

(1)
Section of Atherosclerosis and Vascular Medicine, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
(2)
The Methodist DeBakey Heart & Vascular Center, Houston, TX, USA

Copyright

© Brunner et al; licensee BioMed Central Ltd. 2012

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/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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