Dark Regions of No-Reflow on Late Gadolinium Enhancement Magnetic Resonance Imaging Result in Scar Formation After Atrial Fibrillation Ablation

McGann, Christopher; Kholmovski, Eugene; Blauer, Joshua; Vijayakumar, Sathya; Haslam, Thomas; Cates, Joshua; DiBella, Edward; Burgon, Nathan; Wilson, Brent D.; Alexander, A. L.; Prastawa, Marcel; Daccarett, Marcos; Vergara, Gaston; Akoum, Nazem; Parker, Dennis L.; MacLeod, Rob S.; Marrouche, Nassir F.

doi:10.1016/j.jacc.2011.04.008

Cited by 106 publications

(81 citation statements)

References 25 publications

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“…19 During late-gadolinium MRI performed immediately after ablation, both nonenhancing and hyperenhancing tissue types are seen, the former being a poor predictor of scar visualized at 3-month follow-up. 17 This is likely to reflect ablated but not necessarily necrotic tissue confirming previous work, including that from our own laboratory, that DE MRI overestimates the acute extent of tissue injury after left atrial catheter intervention by virtue of the accumulation of gadolinium in extravascular water associated with acute inflammation. Although there is a good correlation between endocardial voltage-defined scar and T2-weighted signal immediately after ablation, there is a poor correlation with the DE MRI-defined scar at 3-month follow-up, 20 further supporting the transient nature of at least part of the ablation injury process.…”

Section: Discussionsupporting

confidence: 78%

“…7,8,14,15 However, MRI of acute, reversible atrial injury after catheter ablation has only been recently reported. 16,17 There is evidence from animal studies that tissue edema causes right atrial wall thickening after linear ablation in the right atrium. 18 Left atrial edema most likely occurs during and immediately after AF ablation, as evidenced by an increase in atrial wall thickness, and resolves within 1 month.…”

Section: Discussionmentioning

confidence: 99%

“…Although there is a lack of clarity of what DE+T2 signals truly represent in the immediate aftermath of a catheter ablation procedure, the presence of a DE signal beyond 3-month follow-up is likely to represent permanent atrial scarring. 17,24 The formation of scar after ablation and its representation by DE+T2 sequences are not completely understood. However, there are some similarities with findings of a DE signal observed in serial CMRI (acute and late) after acute myocardial infarction, with regression of delayed enhancement areas over time.…”

Section: Atrial Scar and Arrhythmia Recurrencementioning

confidence: 99%

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Acute Pulmonary Vein Isolation Is Achieved by a Combination of Reversible and Irreversible Atrial Injury After Catheter Ablation

Arujuna

Karim

Caulfield

et al. 2012

Circ: Arrhythmia and Electrophysiology

121

107

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Background-Pulmonary vein reconnection after pulmonary vein isolation is common and is usually associated with recurrences of atrial fibrillation. We used cardiac magnetic resonance imaging after radiofrequency ablation to investigate the hypothesis that acute pulmonary vein isolation results from a combination of irreversible and reversible atrial injury. Methods and Results-Delayed enhancement (DE; representing areas of acute tissue injury/necrosis) and T2-weighted (representing tissue water content, including edema) cardiac magnetic resonance scans were performed before, immediately after (acute), and later than 3 months (late) after pulmonary vein isolation in 25 patients with paroxysmal atrial fibrillation undergoing wide-area circumferential ablation. Images were analyzed as pairs of pulmonary veins to quantify the percentage of circumferential antral encirclement composed of DE, T2, and combined DE+T2 signal. Fourteen of 25 patients were atrial fibrillation free at 11-month follow-up (interquartile range, 8-16 months). These patients had higher DE (71±6.0%) and lower T2 signal (72±7.8%) encirclement on the acute scans compared with recurrences (DE, 55±9.1%; T2, 85±6.3%; P<0.05). Patients maintaining sinus rhythm had a lesser decline in DE between acute and chronic scans compared with recurrences (71±6.0% and 60±5.8% versus 55±9.1% and 34±7.3%, respectively). The percentage of encirclement by a combination of DE+T2 was almost similar in both groups on the acute scans (atrial fibrillation free, 89±5.4%; recurrences, 92±4.8%) but different on the chronic scans (60±5.7% versus 34±7.3%). Conclusions-The higher T2 signal on acute scans and greater decline in DE on chronic imaging in patients with recurrences suggest that they have more reversible tissue injury, providing a potential mechanism for pulmonary vein reconnection, resulting in arrhythmia recurrence. (Circ Arrhythm Electrophysiol. 2012;5:691-700.)

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Section: Discussionsupporting

confidence: 78%

Section: Discussionmentioning

confidence: 99%

Section: Atrial Scar and Arrhythmia Recurrencementioning

confidence: 99%

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Acute Pulmonary Vein Isolation Is Achieved by a Combination of Reversible and Irreversible Atrial Injury After Catheter Ablation

Arujuna

Karim

Caulfield

et al. 2012

Circ: Arrhythmia and Electrophysiology

121

107

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“…As a second consideration, a recent study reported that the scar size measured 3 months after ablation with LGE images is <50% of that measured acutely. 6 One of the possible reasons for this © 2014 American Heart Association, Inc. Original Article…”

Section: Clinical Perspective On P 727mentioning

confidence: 99%

Intrinsic Contrast for Characterization of Acute Radiofrequency Ablation Lesions

Çelik

Ramanan

Barry

et al. 2014

Circ: Arrhythmia and Electrophysiology

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Cardiac arrhythmias reflect abnormal electric activity in the heart. Radiofrequency ablation (RFA) is used to treat different arrhythmias by thermally damaging tissue regions and eliminating irregular action potential propagation paths. To ensure a permanent electric block, RFA must create a continuous line of transmural lesions.1 Notwithstanding extensive efforts, the success rates of the RFA operations are still low, 2 likely because of the lack of tools to validate the lesion extent. Current ablation methods rely on suboptimal fluoroscopy and electrophysiology electroanatomic systems; fluoroscopy has poor soft tissue contrast, and even with electroanatomic systems locating and characterizing the ablation lesions are challenging. More importantly, it is difficult to predict which of the lesions that yield a conduction block in the acute setting will maintain a block in the chronic setting. Clinical Perspective on p 727MRI is a powerful tool to detect ablation lesions because of its high soft tissue contrast. Double inversion fast spin echo (DIR) sequence demonstrates intrinsic T 2 -weighted contrast and quickly detect lesions, but DIR images lack specificity and provide poor border visibility. 3,4 Late gadolinium enhancement (LGE) methods provide high contrast between healthy myocardium and the ablation lesions. 3,[5][6][7] However, acute lesion appearance on the LGE image varies with the time between the Gd-DTPA injection and image acquisition because of the wash-in/wash-out kinetics, 7 particularly in areas associated with microvascular obstruction. Shortly after Gd-DTPA injection, the lesion contains hypoenhanced regions in typical LGE acquisitions. Then Gd-DTPA starts to enter the lesion, and a bright rim becomes visible. As the bright rim expands toward the center of the lesion over the ensuing minutes, wash-out mechanisms also begin to diminish the contrast at the outer border of the lesion. The lesion severity can also affect the wash-in/wash-out kinetics. As a second consideration, a recent study reported that the scar size measured 3 months after ablation with LGE images is <50% of that measured acutely. 6 One of the possible reasons for this © 2014 American Heart Association, Inc. Original ArticleBackground-Both intrinsic contrast (T 1 and T 2 relaxation and the equilibrium magnetization) and contrast agent (gadolinium)-enhanced MRI are used to visualize and evaluate acute radiofrequency ablation lesions. However, current methods are imprecise in delineating lesion extent shortly after the ablation. Methods and Results-Fifteen lesions were created in the endocardium of 13 pigs. A multicontrast inversion recovery steady state free precession imaging method was used to delineate the acute ablation lesions, exploiting T 1 -weighted contrast. T 2 and M o * maps were also created from fast spin echo data in a subset of pigs (n=5) to help characterize the change in intrinsic contrast in the lesions. Gross pathology was used as reference for the lesion size comparison, and the lesion structures were confirm...

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“…More recently, there has been increasing interest in visualizing the immediate post ablation injury to better understand its effect on LA remodeling and the success of the procedure [8]. Within 24 hours post-ablation, dark regions of no-reflow on LGE MRI have been shown to correlate with regions of myocardium that eventually become scarred [9,10]. Study of the acute ablation injury using T2w sequences also has been described.…”

Section: Discussionmentioning

confidence: 99%

Dynamic T2 Signal Changes on MRI after Radiofrequency Ablation Injury to the Atrial Myocardium

Rassa¹

2015

JCTCD

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Purpose: Radiofrequency Ablation (RFA) is an effective therapy for Atrial Fibrillation (AF) and can result in cure. Post-ablation injury is well visualized on T2 Weighted (T2w) Cardiac Magnetic Resonance Imaging (CMRI) sequences but does not correlate well with scar formation. However, the change in T2 signal over time has not been well described and may still prove to be clinically useful. Methods and Results:A total of 29 patients presenting for Pulmonary Vein Isolation (PVI) for the treatment of AF underwent serial T2w CMRI before and after the procedure. Immediate RFA lesions were characterized by T2w imaging during CMRI guided ablations in a porcine model (6 pigs). All ablation procedures were performed in an Electrophysiology-Magnetic Resonance Imaging (EP-MRI) suite with an imaging on a 3 Tesla scanner. Study of the Left Atrial (LA) injury response on CMRI scans showed increased T2w signal seconds after ablation, involved a majority of the LA wall within 24 hours, and resolved in less than a week. Conclusion:RFA injury to the LA myocardium causes inflammatory changes on T2w MRI that begin immediately after energy delivery and spread rapidly to the surrounding tissue. These MRI findings may be of clinical interest as tissue injury from the initial RFA lesions may influence the success of lesions delivered later in the procedure. Atrium (LA) have been studied with Magnetic Resonance Imaging (MRI) using both Late Gadolinium Enhancement (LGE) and T2-Weighted (T2w) imaging sequences [3,4]. The late post-ablation scar that results from ablation injury to the myocardium can be visualized on LGE MRI and has been described previously [5,6,7]. More recently, there has been increasing interest in visualizing the immediate post ablation injury to better understand its effect on LA remodeling and the success of the procedure [8]. Within 24 hours post-ablation, dark regions of no-reflow on LGE MRI have been shown to correlate with regions of myocardium that eventually become scarred [9,10]. Study of the acute ablation injury using T2w sequences also has been described. Within 24 hours post-ablation, increased T2 signal is seen in regions with injuries both transient (edema and inflammation) and permanent (tissue necrosis becoming scar) [7,11,12,13]. As a result, postablation T2 signal is not seen as a good predictor of subsequent scar formation [14].While post-ablation T2 signal has been shown to increase and even expand beyond the sites of ablation injury [10,13], the time of onset and resolution of T2 signal following ablation is not well studied. In this paper we describe the temporal course of postablation injury on T2w imaging using data from humans and a porcine model. The dynamic T2 signal changes post-ablation and may provide important clinical information when considering the atrial response to RFA injury. MethodsPatient's data was obtained from the patients in the University of Utah AF Database. From June 2009 to December 2012, patients who underwent PVI with posterior and septal wall debulking in our...

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Dark Regions of No-Reflow on Late Gadolinium Enhancement Magnetic Resonance Imaging Result in Scar Formation After Atrial Fibrillation Ablation

Cited by 106 publications

References 25 publications

Acute Pulmonary Vein Isolation Is Achieved by a Combination of Reversible and Irreversible Atrial Injury After Catheter Ablation

Acute Pulmonary Vein Isolation Is Achieved by a Combination of Reversible and Irreversible Atrial Injury After Catheter Ablation

Intrinsic Contrast for Characterization of Acute Radiofrequency Ablation Lesions

Dynamic T2 Signal Changes on MRI after Radiofrequency Ablation Injury to the Atrial Myocardium

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