Magnetic resonance image intensity ratio, a normalized measure to enable interpatient comparability of left atrial fibrosis

Khurram, Irfan M.; Beinart, Roy; Zipunnikov, Vadim; Dewire, Jane; Yarmohammadi, Hirad; Sasaki, Takeshi; Spragg, David D.; Marine, Joseph E.; Berger, Ronald D.; Halperin, Henry R.; Calkins, Hugh; Zimmerman, Stefan L.; Nazarian, Saman

doi:10.1016/j.hrthm.2013.10.007

Cited by 153 publications

(165 citation statements)

References 20 publications

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“…Images were processed off-line using QMass MR software (version 7.2; Leiden University Medical Center, Leiden, The Netherlands) as previously reported. 8 LA endocardial contours were manually drawn for 30 phases of the cardiac cycle in all slices covering the entire LA. The LA appendage was excluded.…”

Section: Cardiac Magnetic Resonance Imagingmentioning

confidence: 99%

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Association Between Left Atrial Stiffness Index and Atrial Fibrillation Recurrence in Patients Undergoing Left Atrial Ablation

Khurram

Maqbool

Berger

et al. 2016

Circ: Arrhythmia and Electrophysiology

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Background-Atrial fibrillation (AF) is associated with significant abnormalities of left atrial (LA) systolic and diastolic function. This study describes a novel measure, LA stiffness index, that estimates LA diastolic function and its association with clinical outcomes of catheter ablation. Methods and Results-A total of 219 AF patients referred for ablation (59% paroxysmal, mean CHA 2 DS 2 VASc score 1.7±1.4) were enrolled. Atrial pressure and volume loops were prepared from invasive pressure measures and cardiac magnetic resonance imaging volumetric data during sinus rhythm for all patients. An LA stiffness index was created, defined by the ratio of change in LA pressure to volume during passive filling of LA (ΔP/ΔV). Patients were followed prospectively. Mean LA stiffness index for AF patients was 0.6±0.5 mm Hg/mL (paroxysmal AF 0.51±0.4 and persistent AF 0.73±0.6; P<0.001). Linear regression analysis showed a rise in the stiffness index with age, increasing at a rate of 0.02 mm Hg/mL per year (P<0.001). The LA stiffness index was higher in patients with previous LA ablation(s) for AF (0.51±0.35 versus 0.83±0.70; P<0.001). Forty of 160 patients had recurrence after AF ablation with a mean follow-up of 10.4±7.6 months. Patients with recurrence had higher stiffness index than those without recurrence (0.83±0.46 versus 0.40±0.22; P<0.001). Conclusions-LA stiffness index, a novel measure to assess LA diastolic function, increases with age and is higher in persistent AF and in the setting of repeat AF ablation. Greater LA stiffness index was independently associated with recurrence of AF after LA ablation. (Circ Arrhythm Electrophysiol. 2016;9:e003163.

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Section: Cardiac Magnetic Resonance Imagingmentioning

confidence: 99%

“…8,9 AF catheter ablation (CA) using pulmonary vein isolation by wide-area circumferential ablation has been used to decrease the burden of disease and improve AF-free survival. 10 Maintenance of sinus rhythm after ablation is associated with reverse remodeling, decreasing LA size and improving left ventricular (LV) function.…”

mentioning

confidence: 99%

Association Between Left Atrial Stiffness Index and Atrial Fibrillation Recurrence in Patients Undergoing Left Atrial Ablation

Khurram

Maqbool

Berger

et al. 2016

Circ: Arrhythmia and Electrophysiology

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“…[10][11][12] As such, there is an urgent need to develop new approaches for the treatment of complex atrial arrhythmias that incorporate understanding of contributions from the fibrotic remodelled tissue and are tailored to the individual patient. Given that late gadolinium-enhanced magnetic resonance imaging (LGE-MRI) can now be used to reconstruct each patient's unique fibrotic substrate, [13][14][15] the ultimate hope is that information extracted from such scans can be leveraged to guide powerful new ablation approaches that are custom-tailored to render the initiation and perpetuation of atrial re-entry in the given patient impossible. However, attempts to put this into practice have been greatly hindered by a dearth of understanding regarding how each individual's specific distribution of fibrotic tissue affects arrhythmia dynamics.…”

Section: Introductionmentioning

confidence: 99%

Towards personalized computational modelling of the fibrotic substrate for atrial arrhythmia

2016

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Atrial arrhythmias involving a fibrotic substrate are an important cause of morbidity and mortality. In many cases, effective treatment of such rhythm disorders is severely hindered by a lack of mechanistic understanding relating features of fibrotic remodelling to dynamics of re-entrant arrhythmia. With the advent of clinical imaging modalities capable of resolving the unique fibrosis spatial pattern present in the atria of each individual patient, a promising new research trajectory has emerged in which personalized computational models are used to analyse mechanistic underpinnings of arrhythmia dynamics based on the distribution of fibrotic tissue. In this review, we first present findings that have yielded a robust and detailed biophysical representation of fibrotic substrate electrophysiological properties. Then, we summarize the results of several recent investigations seeking to use organ-scale models of the fibrotic human atria to derive new insights on mechanisms of arrhythmia perpetuation and to develop novel strategies for model-assisted individualized planning of catheter ablation procedures for atrial arrhythmias.

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“…Although the atrial wall is thinner, native fibrosis and ablation scar can be identified using primarily threedimensional LGE techniques. 2,11 Findings from some studies have been interpreted to suggest that successful ablation of fibrotic regions, distant to the pulmonary veins (PVs), may help improve AF ablation success rates. 12 Similarly, atrial re-entrant circuits can be modelled in silico based on atrial scar location and can be used to inform ablation strategies.…”

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confidence: 99%

Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology

Chubb

Williams

Whitaker

et al. 2017

Arrhythmia &Amp; Electrophysiology Review

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Interventional magnetic resonance imaging (MRI) is a growing field, and the strength of MRI guidance for procedures rests fundamentally in the high-contrast imaging of soft tissue structures. Combined with the avoidance of radiation exposure, the potential for functional assessment and the ability to exploit MR signals for calculation of the location of interventional instruments, it is clear that the implementation of interventional MRI will continue to grow. For general cardiac interventions, the visualisation of thin, mobile structures presents particular challenges for MRI guidance. Cardiac electrophysiological (EP) procedures add a further dimension, as the accurate detection of intracardiac electrograms must be performed in a highly active electromagnetic environment. This review focuses on the technical considerations for the performance of EP procedures under MRI guidance (MR-guided EP). Potential Benefits of MR-guided Electrophysiological ProceduresMRI techniques offer a high soft-tissue contrast-to-noise ratio (CNR) in comparison with that seen with X-ray, computed tomography (CT) and ultrasound. However, the environment can present challenges and is an expensive procedure; therefore, all the benefits of MR-guided EP must be fully considered to justify the additional difficulties and expense. Broadly speaking, these benefits can be divided into three main areas: improved precision of ablation targeting (substrate identification), improved intra-procedural guidance and improved assessment of ablation lesion formation. Emerging data also suggest that CMR imaging may be used to guide atrial ablation procedures. Although the atrial wall is thinner, native fibrosis and ablation scar can be identified using primarily threedimensional LGE techniques. 2,11 Findings from some studies have been interpreted to suggest that successful ablation of fibrotic regions, distant to the pulmonary veins (PVs), may help improve AF ablation success rates. 12 Similarly, atrial re-entrant circuits can be modelled in silico based on atrial scar location and can be used to inform ablation strategies. 13 Sites of PV reconnection have been identified using CMR, with successful ablation guided by the CMR-derived substrate, 14 but these findings have not been replicated in all studies. Substrate Identification 15To date, all studies that have used CMR-derived substrate identification to guide ablation have relied on fusion of the imaging to electroanatomic Abstract MR-guidance of electrophysiological (EP) procedures offers the potential for enhanced arrhythmia substrate assessment, improved procedural guidance and real-time assessment of ablation lesion formation. Accurate device tracking techniques, using both active and passive methods, have been developed to offer an interface similar to electroanatomic mapping platforms, and MR-compatible EP equipment continues to be developed. Progress to clinical implementation of these technically complex fields has been relatively slow over the last 10 years, but recent developments have...

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Magnetic resonance image intensity ratio, a normalized measure to enable interpatient comparability of left atrial fibrosis

Abstract: Background-The measurement of late gadolinium enhanced MRI (LGE-MRI) intensity in arbitrary units (au), limits the objectivity of thresholds for focal scar detection and inter-patient comparisons of scar burden.

Cited by 153 publications

References 20 publications

Association Between Left Atrial Stiffness Index and Atrial Fibrillation Recurrence in Patients Undergoing Left Atrial Ablation

Association Between Left Atrial Stiffness Index and Atrial Fibrillation Recurrence in Patients Undergoing Left Atrial Ablation

Towards personalized computational modelling of the fibrotic substrate for atrial arrhythmia

Cardiac Electrophysiology Under MRI Guidance: an Emerging Technology

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