Cardiovascular Magnetic Resonance Imaging of Scar Development Following Pulmonary Vein Isolation: A Prospective Study
Josephson ME (2014) Cardiovascular Magnetic Resonance Imaging of Scar Development Following
Pulmonary Vein Isolation: A Prospective Study. PLoS ONE 9(9): e104844. doi:10.1371/journal.pone.0104844
Cardiovascular Magnetic Resonance Imaging of Scar Development Following Pulmonary Vein Isolation: A Prospective Study
Jeff Hsing 0
Dana C. Peters 0
Benjamin R. Knowles 0
Warren J. Manning 0
Mark E. Josephson 0
Rory Edward Morty, University of Giessen Lung Center, Germany
0 1 Department of Medicine, Cardiovascular Division, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston , Massachusetts, United States of America, 2 Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School , Boston , Massachusetts, United States of America, 3 Department of Radiology, Yale Medical School , New Haven, Connecticut , United States of America
Aims: Cardiovascular magnetic resonance (MR) provides non-invasive assessment of early (24-hour) edema and injury following pulmonary vein isolation (by ablation) and subsequent scar formation. We hypothesize that 24-hours after ablation, cardiovascular MR would demonstrate a pattern of edema and injury due to ablation and the severity would correlate with subsequent scar. Methods: Fifteen atrial fibrillation patients underwent cardiovascular MR prior to pulmonary vein isolation, 24-hours post (N = 11) and 30-days post (N = 7) ablation, with T2-weighted (T2W) and late gadolinium enhancement (LGE) imaging. Left atrial wall thickness, edema enhancement ratio and LGE enhancement were assessed at each time point. Volumes of LGE and edema enhancement were measured, and the circumferential presence of injury was assessed at 24-hours, including comparison with LGE enhancement at 30 days. Results: Left atrial wall thickness was increased 24-hours post-ablation (10.764.1 mm vs. 7.061.8 mm pre-PVI, p,0.05). T2W enhancement at 24-hours showed increased edema enhancement ratio (1.560.4 for post-ablation, vs. 0.960.2 preablation, p,0.001). Edema and LGE volumes at 24-hours were correlated with 30-day LGE volume (R = 0.76, p = 0.04, and R = 0.74, p = 0.09, respectively). Using a 16 segment model for assessment, 24-hour T2W had sensitivity, specificity, and accuracy of 82%, 63%, and 79% respectively, for predicting 30-day LGE. 24-hour LGE had sensitivity, specificity, and accuracy of 91%, 47%, and 84%. Conclusions: Increased left atrial wall thickening and edema were characterized on cardiovascular MR early post-ablation, and found to correlate with 30-day LGE scar.
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Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. All relevant data are within the paper and its
Supporting Information files.
Funding: This work was supported by in part by grants from the NIH (NHLBI R21 HL 098573 & R21 HL103463). The funders had no role in study design, data
collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interests: The authors have declared that no competing interests exist.
. These authors contributed equally to this work.
Atrial fibrillation (AF) is the most common sustained
arrhythmia, with substantial associated morbidity and mortality [1].
Pulmonary vein isolation (PVI) has been advocated as a therapy
for AF, with freedom from AF reported in 60% to 85% of patients
with paroxysmal AF [2]. Recurrence also depends on follow-up
duration [3].
A suspected cause of AF recurrence is incomplete
circumferential PVI ablation with associated electrical reconnection of the PVs
to the left atrium (LA) [46]. One hypothesis to explain early (,30
days) (but not late) isolation after PVI is that the PVI procedure
causes early focal reversible edema without permanent injury,
resulting in only temporary electrical isolation. After the edema
resolves, the PVs are electrically reconnected. During the PVI
procedure, the extent of injury that is created during PVI is
unknown, as neither fluoroscopy nor electroanatomical mapping
allows for discrimination of the ablation lesions.
Cardiovascular magnetic resonance (CMR) is a non-invasive
imaging modality that allows for identification of myocardial scar
[7,8], and edema [9] using late gadolinium enhancement (LGE)
and T2-weighted (T2w) imaging, respectively. Animal studies have
shown a close correspondence between CMR and injury after RF
ablation [10,11].
LGE CMR is also able to identify LA and PV scar late ($30
days) after ablation, showing a trend of more extensive scarring in
subjects who later recur [1214]. Further, in patients undergoing
redo procedures, isolated PVs had greater amount of ostial scar by
LGE (43%) vs. those which were reconnected (21%) [15].
Therefore, it may be valuable to acutely identify PVs which will
exhibit insufficient chronic scarring. Recent CMR studies have
examined and characterized the development of LGE after
ablation, comparing early and later imaging findings [11
13,16,17]. A critical issue for the (...truncated)