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Hussain S, Falanga M, Chiaravalloti A, Tomasi C, Corsi C. Patient-specific left atrium contraction quantification associated with atrial fibrillation: A region-based approach. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2024; 249:108138. [PMID: 38522329 DOI: 10.1016/j.cmpb.2024.108138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 03/17/2024] [Accepted: 03/18/2024] [Indexed: 03/26/2024]
Abstract
BACKGROUND AND OBJECTIVES Atrial fibrillation (AF) is a widespread cardiac arrhythmia that significantly impacts heart function. AF disrupts atrial mechanical contraction, leading to irregular, uncoordinated, and slow blood flow inside the atria which favors the formation of clots, primarily within the left atrium (LA). A standardized region-based analysis of the LA is missing, and there is not even any consensus about how to define the LA regions. In this study we propose an automatic approach for regionalizing the LA into segments to provide a comprehensive 3D region-based LA contraction assessment. LA global and regional contraction were quantified in control subjects and in AF patients to describe mechanical abnormalities associated with AF. METHODS The proposed automatic approach for LA regionalization was tested in thirteen control subjects and seventeen AF patients. After dividing LA into standard regions, we evaluated the global and regional mechanical function by measuring LA contraction parameters, such as regional volume, global and regional strains, regional wall motion and regional shortening fraction. RESULTS LA regionalization was successful in all study subjects. In the AF group compared with control subjects, results showed: a global impairment of LA contraction which appeared more pronounced along radial and circumferential direction; a regional impairment of radial strain which was more pronounced in septal, inferior, and lateral regions suggesting a greater reduction in mechanical efficiency in these regions in comparison to the posterior and anterior ones. CONCLUSION An automatic approach for LA regionalization was proposed. The regionalization method was proved to be robust with several LA anatomical variations and able to characterize contraction changes associated with AF.
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Affiliation(s)
| | | | | | - Corrado Tomasi
- Santa Maria delle Croci Hospital, AUSL della Romagna, Ravenna, Italy
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Sillett C, Razeghi O, Lee AWC, Solis Lemus JA, Roney C, Mannina C, de Vere F, Ananthan K, Ennis DB, Haberland U, Xu H, Young A, Rinaldi CA, Rajani R, Niederer SA. A three-dimensional left atrial motion estimation from retrospective gated computed tomography: application in heart failure patients with atrial fibrillation. Front Cardiovasc Med 2024; 11:1359715. [PMID: 38596691 PMCID: PMC11002108 DOI: 10.3389/fcvm.2024.1359715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 03/08/2024] [Indexed: 04/11/2024] Open
Abstract
Background A reduced left atrial (LA) strain correlates with the presence of atrial fibrillation (AF). Conventional atrial strain analysis uses two-dimensional (2D) imaging, which is, however, limited by atrial foreshortening and an underestimation of through-plane motion. Retrospective gated computed tomography (RGCT) produces high-fidelity three-dimensional (3D) images of the cardiac anatomy throughout the cardiac cycle that can be used for estimating 3D mechanics. Its feasibility for LA strain measurement, however, is understudied. Aim The aim of this study is to develop and apply a novel workflow to estimate 3D LA motion and calculate the strain from RGCT imaging. The utility of global and regional strains to separate heart failure in patients with reduced ejection fraction (HFrEF) with and without AF is investigated. Methods A cohort of 30 HFrEF patients with (n = 9) and without (n = 21) AF underwent RGCT prior to cardiac resynchronisation therapy. The temporal sparse free form deformation image registration method was optimised for LA feature tracking in RGCT images and used to estimate 3D LA endocardial motion. The area and fibre reservoir strains were calculated over the LA body. Universal atrial coordinates and a human atrial fibre atlas enabled the regional strain calculation and the fibre strain calculation along the local myofibre orientation, respectively. Results It was found that global reservoir strains were significantly reduced in the HFrEF + AF group patients compared with the HFrEF-only group patients (area strain: 11.2 ± 4.8% vs. 25.3 ± 12.6%, P = 0.001; fibre strain: 4.5 ± 2.0% vs. 15.2 ± 8.8%, P = 0.001), with HFrEF + AF patients having a greater regional reservoir strain dyssynchrony. All regional reservoir strains were reduced in the HFrEF + AF patient group, in whom the inferior wall strains exhibited the most significant differences. The global reservoir fibre strain and LA volume + posterior wall reservoir fibre strain exceeded LA volume alone and 2D global longitudinal strain (GLS) for AF classification (area-under-the-curve: global reservoir fibre strain: 0.94 ± 0.02, LA volume + posterior wall reservoir fibre strain: 0.95 ± 0.02, LA volume: 0.89 ± 0.03, 2D GLS: 0.90 ± 0.03). Conclusion RGCT enables 3D LA motion estimation and strain calculation that outperforms 2D strain metrics and LA enlargement for AF classification. Differences in regional LA strain could reflect regional myocardial properties such as atrial fibrosis burden.
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Affiliation(s)
- Charles Sillett
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Orod Razeghi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Department of Haematology, University of Cambridge, Cambridge, United Kingdom
| | - Angela W. C. Lee
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Jose Alonso Solis Lemus
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
| | - Caroline Roney
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Carlo Mannina
- Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Felicity de Vere
- Department of Cardiology, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Kiruthika Ananthan
- Department of Cardiology, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Daniel B. Ennis
- Department of Radiology, Stanford University, Stanford, CA, United States
| | | | - Hao Xu
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Alistair Young
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
| | - Christopher A. Rinaldi
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Department of Cardiology, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Ronak Rajani
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- Department of Cardiology, Guy’s and St Thomas’ NHS Foundation Trust, London, United Kingdom
| | - Steven A. Niederer
- School of Biomedical Engineering and Imaging Sciences, King’s College London, London, United Kingdom
- National Heart and Lung Institute, Imperial College London, London, United Kingdom
- Turing Research and Innovation Cluster: Digital Twins, The Alan Turing Institute, London, United Kingdom
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Alfalahi H, Renda F, Stefanini C. Concentric Tube Robots for Minimally Invasive Surgery: Current Applications and Future Opportunities. ACTA ACUST UNITED AC 2020. [DOI: 10.1109/tmrb.2020.3000899] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Phung TKN, Moyer CB, Norton PT, Ferguson JD, Holmes JW. Effect of ablation pattern on mechanical function in the atrium. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2017; 40:648-654. [PMID: 28370137 DOI: 10.1111/pace.13086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 03/06/2017] [Accepted: 03/27/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is often treated with catheter ablation, which induces scar formation to isolate misfiring electrical signals in the left atrium. Successful ablation restores sinus rhythm at the cost of replacing viable myocardium with scar. The impact of ablation scar on mechanical function of the left atrium is poorly understood. OBJECTIVE We used a computational model to simulate various ablation patterns and determine their effect on atrial global and regional mechanical function. METHODS A coupled finite-element and hemodynamic circuit model of the left atrium that represents the regional and global mechanics in paroxysmal AF patients was modified to simulate different ablation patterns: step-wise pulmonary vein isolation (PVI), wide area circumferential ablation (WACA), and a posterior ablation developed by nContact, Inc (Morrisville, NC, USA). Atrial pressure-volume relationships and regional wall motion were compared among the models. RESULTS Ablation increased passive stiffness and decreased active work performed by the atrium. Active emptying volume decreased with increasing scar by up to 44% (11 mL) at a scar volume of 31%. At matched scar volumes, WACA decreased active emptying more severely than PVI and nContact. Similarly, wall motion was depressed most in the WACA model because WACA involved portions of the lateral wall with higher baseline motion. CONCLUSION Simulated ablation depressed atrial mechanical function to an extent that depended on both scar volume and location, primarily through reducing active emptying. Placing ablation scar in regions with high baseline motion resulted in greater depression of active function, while ablation of the posterior wall was less disruptive.
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Affiliation(s)
- Thien-Khoi N Phung
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Christian B Moyer
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA
| | - Patrick T Norton
- Department of Radiology, University of Virginia, Charlottesville, VA
| | - John D Ferguson
- Department of Medicine, University of Virginia, Charlottesville, VA
| | - Jeffrey W Holmes
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA.,Department of Medicine, University of Virginia, Charlottesville, VA.,Robert M. Berne Cardiovascular Center, University of Virginia, Charlottesville, VA
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Holmes JW, Laksman Z, Gepstein L. Making better scar: Emerging approaches for modifying mechanical and electrical properties following infarction and ablation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2015; 120:134-48. [PMID: 26615948 DOI: 10.1016/j.pbiomolbio.2015.11.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/13/2015] [Accepted: 11/20/2015] [Indexed: 12/31/2022]
Abstract
Following myocardial infarction (MI), damaged myocytes are replaced by collagenous scar tissue, which serves an important mechanical function - maintaining integrity of the heart wall against enormous mechanical forces - but also disrupts electrical function as structural and electrical remodeling in the infarct and borderzone predispose to re-entry and ventricular tachycardia. Novel emerging regenerative approaches aim to replace this scar tissue with viable myocytes. Yet an alternative strategy of therapeutically modifying selected scar properties may also prove important, and in some cases may offer similar benefits with lower risk or regulatory complexity. Here, we review potential goals for such modifications as well as recent proof-of-concept studies employing specific modifications, including gene therapy to locally increase conduction velocity or prolong the refractory period in and around the infarct scar, and modification of scar anisotropy to improve regional mechanics and pump function. Another advantage of scar modification techniques is that they have applications well beyond MI. In particular, ablation treats electrical abnormalities of the heart by intentionally generating scar to block aberrant conduction pathways. Yet in diseases such as atrial fibrillation (AF) where ablation can be extensive, treating the electrical disorder can significantly impair mechanical function. Creating smaller, denser scars that more effectively block conduction, and choosing the location of those lesions by balancing their electrical and mechanical impacts, could significantly improve outcomes for AF patients. We review some recent advances in this area, including the use of computational models to predict the mechanical effects of specific lesion sets and gene therapy for functional ablation. Overall, emerging techniques for modifying scar properties represents a potentially important set of tools for improving patient outcomes across a range of heart diseases, whether used in place of or as an adjunct to regenerative approaches.
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Affiliation(s)
- Jeffrey W Holmes
- Departments of Biomedical Engineering and Medicine, Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA, United States.
| | - Zachary Laksman
- Cardiac Electrophysiology, University of British Columbia, Vancouver, BC, Canada
| | - Lior Gepstein
- Departments of Cardiology (Ramban Health Care Campus) and Physiology, The Rappaport Faculty of Medicine and Research Institute, Technion - Israel Institute of Technology, Haifa, Israel
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Al-Issa A, Inoue Y, Cammin J, Tang Q, Nazarian S, Calkins H, Fishman EK, Taguchi K, Ashikaga H. Regional function analysis of left atrial appendage using motion estimation CT and risk of stroke in patients with atrial fibrillation. Eur Heart J Cardiovasc Imaging 2015; 17:788-96. [PMID: 26341293 DOI: 10.1093/ehjci/jev207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 08/02/2015] [Indexed: 11/13/2022] Open
Abstract
AIMS The aim of this article is to determine the association between left atrial appendage (LAA) regional dysfunction using image-based motion-estimation computed tomography (CT) (iME) and a prior history of stroke or transient ischaemic attack (TIA) in patients with atrial fibrillation (AF). METHODS AND RESULTS In this single-centre retrospective case-control study, among patients referred for AF ablation who underwent pre-ablation cardiac CT with retrospective ECG gating, we identified 18 patients with a prior history of stroke or TIA at the time of CT scan and 18 age- and gender-matched controls. All the patients were in sinus rhythm at the time of CT scan. Four-dimensional motion vector field was estimated from the CT images using iME. To assess myocardial deformation, area change ratio (A) and area change rate (AR) were calculated over the endocardial surface of the LAA. There was no significant difference in the baseline patient characteristics between the stroke/TIA group and the control group (67.6 ± 8.1 years old, 66.7% male, 16.7% persistent AF). LAA maximum (Amax; 23.8 ± 33.0 vs. 52.9 ± 41.2%, P = 0.02) and pre-atrial contraction area change ratio (ApreA; 13.7 ± 17.7 vs. 30.9 ± 29.2%, P = 0.04) were significantly lower in the stroke/TIA group than in the control group, respectively. The difference in LAA Amax and ApreA remained significant in multivariate analysis (P = 0.03 and P = 0.04, respectively). CONCLUSION LAA regional dysfunction is associated with stroke/TIA in AF patients. Our results offer a basis for a prospective study to determine the role of LAA regional dysfunction by iME in predicting cerebrovascular events such as stroke or TIA.
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Affiliation(s)
- Abdullah Al-Issa
- Cardiac Arrhythmia Service, Division of Cardiology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Carnegie 568, Baltimore, MD 21287, USA
| | - Yuko Inoue
- Cardiac Arrhythmia Service, Division of Cardiology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Carnegie 568, Baltimore, MD 21287, USA
| | - Jochen Cammin
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Qiulin Tang
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Saman Nazarian
- Cardiac Arrhythmia Service, Division of Cardiology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Carnegie 568, Baltimore, MD 21287, USA
| | - Hugh Calkins
- Cardiac Arrhythmia Service, Division of Cardiology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Carnegie 568, Baltimore, MD 21287, USA
| | - Elliot K Fishman
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Katsuyuki Taguchi
- The Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hiroshi Ashikaga
- Cardiac Arrhythmia Service, Division of Cardiology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Carnegie 568, Baltimore, MD 21287, USA Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Changes in Global and Regional Mechanics Due to Atrial Fibrillation: Insights from a Coupled Finite-Element and Circulation Model. Ann Biomed Eng 2015; 43:1600-13. [PMID: 25631205 DOI: 10.1007/s10439-015-1256-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Accepted: 01/14/2015] [Indexed: 10/24/2022]
Abstract
Atrial fibrillation (AF) is a rhythm disorder with rapidly increasing prevalence due to the aging of the population. AF triggers structural remodeling and a gradual loss of function; however, the relative contributions of specific features of AF-induced remodeling to changes in atrial mechanical function are unclear. We constructed and validated a finite-element model (FEM) of the normal human left atrium using anatomic information from cardiac magnetic resonance imaging, material properties and fiber orientations from published studies, and an iterative algorithm to estimate unloaded geometry. We coupled the FEM to a circuit model to capture hemodynamic interactions between the atrium, pulmonary circulation, and left ventricle. The normal model reproduced measured volumes within 1 SD, as well as most metrics of regional mechanics. Using this validated human model as a starting point, we explored the impact of individual features of atrial remodeling on atrial mechanics and found that a combination of dilation, increased pressure, and fibrosis can explain most of the observed changes in mechanics in patients with paroxysmal AF. However, only impaired ventricular relaxation could reproduce the increased reliance on active emptying we observed in these patients. The resulting model provides new insight into the mechanics of AF and a platform for exploring future therapies.
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