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Shang S, Li G, Lin L. A method of source localization for bioelectricity based on “Orthogonal Differential Potential”. Biomed Signal Process Control 2021. [DOI: 10.1016/j.bspc.2021.103054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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2
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Lu Z, Jiang D, Yang J. A method for magnetocardiography functional localization based on boundary element method and Nelder-Mead simplex algorithm. Ann Noninvasive Electrocardiol 2021; 26:e12879. [PMID: 34250679 PMCID: PMC8588379 DOI: 10.1111/anec.12879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The magnetocardiography (MCG) functional localization can transfer the biomagnetic signal to the electrical activity information inside the heart. The electrical activity is directly related to the physiological function of the heart. METHODS This study proposes a practical method for MCG functional localization based on the boundary element method (BEM) and the Nelder-Mead (NM) simplex algorithm. Single equivalent moving current dipole (SEMCD) is served as the equivalent cardiac source. The parameters of SEMCD are adapted using the NM simplex algorithm by fitting the measured MCG with the calculated MCG obtained based on BEM. The SEMCD parameters are solved in the sense that the difference between measured and calculated MCG is minimized. RESULTS The factors affecting the localization accuracy of this BEM-NM method were first explored with synthetic signals. Then, the results with real MCG signals show a good agreement between the SEMCD location and the region where ventricle depolarization starts, demonstrating the feasibility of this idea. CONCLUSIONS This is the first three-dimensional localization of the onset of ventricular depolarization with the BEM-NM method. The method is promising in the noninvasive localization of lesions for heart diseases.
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Affiliation(s)
- Zhihong Lu
- Department of Precision Instrument, Tsinghua University, Beijing, China.,Beijing Innovation Center for Future Chips, Beijing, China.,The State Key Laboratory of Precision Measurement Technology and Instruments, Beijing, China
| | - Dingsong Jiang
- Department of Precision Instrument, Tsinghua University, Beijing, China.,Beijing Innovation Center for Future Chips, Beijing, China.,The State Key Laboratory of Precision Measurement Technology and Instruments, Beijing, China
| | - Jianzhong Yang
- Department of Precision Instrument, Tsinghua University, Beijing, China.,Beijing Innovation Center for Future Chips, Beijing, China.,The State Key Laboratory of Precision Measurement Technology and Instruments, Beijing, China
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Lv W, Lee K, Arai T, Barrett CD, Hasan MM, Hayward AM, Marini RP, Barley ME, Galea A, Hirschman G, Armoundas AA, Cohen RJ. Accuracy of cardiac ablation catheter guidance by means of a single equivalent moving dipole inverse algorithm to identify sites of origin of cardiac electrical activation. J Interv Card Electrophysiol 2019; 58:323-331. [DOI: 10.1007/s10840-019-00605-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 08/02/2019] [Indexed: 12/19/2022]
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Meglan DA, Lv W, Cohen RJ, Riviere CN. Techniques for epicardial mapping and ablation with a miniature robotic walker. ROBOTIC SURGERY : RESEARCH AND REVIEWS 2017; 4:25-31. [PMID: 28966928 PMCID: PMC5619864 DOI: 10.2147/rsrr.s127047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background Present treatments for ventricular tachycardia have significant drawbacks. To ameliorate these drawbacks, it may be advantageous to employ an epicardial robotic walker that performs mapping and ablation with precise control of needle insertion depth. This paper examines the feasibility of such a system. Methods This paper describes the techniques for epicardial mapping and depth-controlled ablation with the robotic walker. The mapping technique developed for the current form of the system uses a single equivalent moving dipole (SEMD) model combined with the navigation capability of the walker. The intervention technique provides saline-enhanced radio frequency ablation, with sensing of needle penetration depth. The mapping technique was demonstrated in an artificial heart model with a simulated arrhythmia focus, followed by preliminary testing in the porcine model in vivo. The ablation technique was demonstrated in an artificial tissue model and then in chicken breast tissue ex vivo. Results The walker located targets to within 2 mm by using the SEMD mapping technique. No epicardial damage was found subsequent to the porcine trial in vivo. Needle insertion for ablation was controlled to within 2 mm of the target depth. Lesion size was repeatable, with diameter varying consistently in proportion to the volume of saline injected. Conclusion The experiments demonstrated the general feasibility of the techniques for mapping and depth-controlled ablation with the robotic walker.
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Affiliation(s)
| | - Wener Lv
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Richard J Cohen
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Cameron N Riviere
- The Robotics Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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Sohn K, Armoundas AA. On the efficiency and accuracy of the single equivalent moving dipole method to identify sites of cardiac electrical activation. Med Biol Eng Comput 2016; 54:1611-9. [PMID: 26798056 DOI: 10.1007/s11517-015-1437-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 12/11/2015] [Indexed: 01/14/2023]
Abstract
We have proposed an algorithm to guide radiofrequency catheter ablation procedures. This algorithm employs the single equivalent moving dipole (SEMD) to model cardiac electrical activity. The aim of this study is to investigate the optimal time instant during the cardiac cycle as well as the number of beats needed to accurately estimate the location of a pacing site. We have evaluated this algorithm by pacing the ventricular epicardial surface and inversely estimating the locations of pacing electrodes from the recorded body surface potentials. Two pacing electrode arrays were sutured on the right and left ventricular epicardial surfaces in swine. The hearts were paced by the electrodes sequentially at multiple rates (120-220 bpm), and body surface ECG signals from 64 leads were recorded for the SEMD estimation. We evaluated the combined error of the estimated interelectrode distance and SEMD direction at each time instant during the cardiac cycle, and found the error was minimum when the normalized root mean square (RMS n ) value of body surface ECG signals reached 15 % of its maximum value. The beat-to-beat variation of the SEMD locations was significantly reduced (p < 0.001) when estimated at 15 % RMS n compared to the earliest activation time (EAT). In addition, the 5-95 % interval of the estimated interelectrode distance error decreased exponentially as the number of beats used to estimate a median beat increased. When the number of beats was 4 or larger, the 5-95 % interval was smaller than 3.5 mm (the diameter of a commonly used catheter). In conclusion, the optimal time for the SEMD estimation is at 15 % of RMS n , and at that time instant a median beat estimated from 4 beats is associated with a beat-to-beat variability of the SEMD location that is appropriate for catheter ablation procedures.
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Affiliation(s)
- Kwanghyun Sohn
- Cardiovascular Research Center, Massachusetts General Hospital, 149 13th Street, Charlestown, Boston, MA, 02129, USA
| | - Antonis A Armoundas
- Cardiovascular Research Center, Massachusetts General Hospital, 149 13th Street, Charlestown, Boston, MA, 02129, USA. .,Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
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Sohn K, Lv W, Lee K, Galea A, Hirschman G, Barrett C, Cohen RJ, Armoundas AA. A method to noninvasively identify cardiac bioelectrical sources. Pacing Clin Electrophysiol 2014; 37:1038-50. [PMID: 24645803 DOI: 10.1111/pace.12380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 01/05/2014] [Accepted: 01/25/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND We have introduced a method to guide radiofrequency catheter ablation (RCA) procedures that estimates the location of a catheter tip used to pace the ventricles and the target site for ablation using the single equivalent moving dipole (SEMD). OBJECTIVE To investigate the accuracy of this method in resolving epicardial and endocardial electrical sources. METHODS Two electrode arrays, each of nine pacing electrodes at known distances from each other, sutured on the left- and right-ventricular (LV and RV) epicardial surfaces of swine, were used to pace the heart at multiple rates, while body surface potentials from 64 sites were recorded and used to estimate the SEMD location. A similar approach was followed for pacing from catheters in the LV and RV. RESULTS The overall (RV & LV) error in estimating the interelectrode distance of adjacent epicardial electrodes was 0.38 ± 0.45 cm. The overall endocardial (RV & LV) interelectrode distance error, was 0.44 ± 0.26 cm. Heart rate did not significantly affect the error of the estimated SEMD location (P > 0.05). The guiding process error became progressively smaller as the SEMD approached an epicardial target site and close to the target, the overall absolute error was ∼ 0.28 cm. The estimated epicardial SEMD locations preserved their topology in image space with respect to their corresponding physical location of the epicardial electrodes. CONCLUSION The proposed algorithm suggests one can efficiently and accurately resolve epicardial electrical sources without the need of an imaging modality. In addition, the error in resolving these sources is sufficient to guide RCA procedures.
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Affiliation(s)
- Kwanghyun Sohn
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts
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Sohn K, Wener Lv, Kichang Lee, Galea AM, Hirschman GB, Hayward AM, Cohen RJ, Armoundas AA. The Single Equivalent Moving Dipole Model Does Not Require Spatial Anatomical Information to Determine Cardiac Sources of Activation. IEEE J Biomed Health Inform 2014; 18:222-30. [DOI: 10.1109/jbhi.2013.2268012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Lee K, Lv W, Ter-Ovanesyan E, Barley ME, Voysey GE, Galea AM, Hirschman GB, Leroy K, Marini RP, Barrett C, Armoundas AA, Cohen RJ. Cardiac ablation catheter guidance by means of a single equivalent moving dipole inverse algorithm. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2013; 36:811-22. [PMID: 23448231 DOI: 10.1111/pace.12114] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 12/14/2012] [Accepted: 01/06/2013] [Indexed: 11/28/2022]
Abstract
BACKGROUND We developed and evaluated a novel system for guiding radiofrequency catheter ablation therapy of ventricular tachycardia. This guidance system employs an inverse solution guidance algorithm (ISGA) using a single equivalent moving dipole (SEMD) localization method. The method and system were evaluated in both a saline tank phantom model and in vivo animal (swine) experiments. METHODS A catheter with two platinum electrodes spaced 3 mm apart was used as the dipole source in the phantom study. A 40-Hz sinusoidal signal was applied to the electrode pair. In the animal study, four to eight electrodes were sutured onto the right ventricle. These electrodes were connected to a stimulus generator delivering 1-ms duration pacing pulses. Signals were recorded from 64 electrodes, located either on the inner surface of the saline tank or on the body surface of the pig, and then processed by the ISGA to localize the physical or bioelectrical SEMD. RESULTS In the phantom studies, the guidance algorithm was used to advance a catheter tip to the location of the source dipole. The distance from the final position of the catheter tip to the position of the target dipole was 2.22 ± 0.78 mm in real space and 1.38 ± 0.78 mm in image space (computational space). The ISGA successfully tracked the locations of electrodes sutured on the ventricular myocardium and the movement of an endocardial catheter placed in the animal's right ventricle. CONCLUSION In conclusion, we successfully demonstrated the feasibility of using an SEMD inverse algorithm to guide a cardiac ablation catheter.
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Affiliation(s)
- Kichang Lee
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
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Lai D, Liu C, Eggen MD, Iaizzo PA, He B. Equivalent moving dipole localization of cardiac ectopic activity in a swine model during pacing. ACTA ACUST UNITED AC 2010; 14:1318-26. [PMID: 20515710 DOI: 10.1109/titb.2010.2051448] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Localization of the initial site of cardiac ectopic activity has direct clinical benefits for treating focal cardiac arrhythmias. The aim of the present study is to experimentally evaluate the performance of the equivalent moving dipole technique on noninvasively localizing the origin of the cardiac ectopic activity from the recorded body surface potential mapping (BSPM) data in a well-controlled experimental setting. The cardiac ectopic activities were induced in four well-controlled intact pigs by either single-site pacing or dual-site pacing within the ventricles. In each pacing study, the initiation sites of cardiac ectopic activity were localized by estimating the locations of a single moving dipole (SMD) or two moving dipoles (TMDs) from the measured BSPM data and compared with the precise pacing sites (PSs). For the single-site pacing, the averaged SMD localization error was 18.6 ± 3.8 mm over 16 sites, while the averaged distance between the TMD locations and the two corresponding PSs was slightly larger (24.9 ± 6.2 mm over five pairs of sites), both occurring at the onset of the QRS complex (10-25 ms following the pacing spike). The obtained SMD trajectories originated near the stimulus site and then traversed across the heart during the ventricular depolarization. The present experimental results show that the initial location of the moving dipole can provide the approximate site of origin of a cardiac ectopic activity in vivo, and that the migration of the dipole can portray the passage of an ectopic beat across the heart.
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Affiliation(s)
- Dakun Lai
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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Lai D, Liu C, Eggen MD, Iaizzo PA, He B. Cardiac source localization by means of a single moving dipole solution during endocardial pacing in an animal model. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2010; 2009:1778-80. [PMID: 19964556 DOI: 10.1109/iembs.2009.5334014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The accuracy of localizing the initiation site of cardiac activation by noninvasively estimating a single moving dipole (SMD) was investigated in a swine model. Body surface potential mapping (BSPM) and intracavitary noncontact mapping (NCM) were performed simultaneously during acute left ventricular (LV) endocardial pacing. For each animal, the boundary element model was constructed from preoperative magnetic resonance images (MRI). In each pacing study, the initiation site was localized by inversely estimating the location of an SMD from BSPM data. The results were compared with the precise pacing sites recorded by the NCM system. In total, four pacing sites from two pigs were analyzed, and the averaged source localization error was 16.8 +/- 2.3 mm. The present results indicate the potential of localizing focal cardiac events by estimating single moving dipole.
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Affiliation(s)
- Dakun Lai
- Department of Biomedical Engineering, 7-105 NHH, 312 Church Street SE, Minneapolis, MN 55455 USA
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Barley ME, Armoundas AA, Cohen RJ. A Method for Guiding Ablation Catheters to Arrhythmogenic Sites Using Body Surface Electrocardiographic Signals. IEEE Trans Biomed Eng 2009; 56:810-9. [DOI: 10.1109/tbme.2008.2006277] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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12
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Method for guiding the ablation catheter to the ablation site: a simulation and experimental study. Med Biol Eng Comput 2009; 47:267-78. [DOI: 10.1007/s11517-009-0441-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 10/22/2008] [Indexed: 10/21/2022]
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Barley ME, Choppy KJ, Galea AM, Armoundas AA, Rosbury TS, Hirschman GB, Cohen RJ. Validation of a novel catheter guiding method for the ablative therapy of ventricular tachycardia in a phantom model. IEEE Trans Biomed Eng 2008; 56:907-10. [PMID: 19272901 DOI: 10.1109/tbme.2008.2006274] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Accurate guidance of an ablation catheter is critical in the RF ablation (RFA) of ventricular tachycardia (VT). With current technologies, it is challenging to rapidly and accurately localize the site of origin of an arrhythmia, often restricting treatment to patients with hemodynamically stable arrhythmias. We investigated the effectiveness of a new guidance method, the inverse solution guidance algorithm (ISGA), which is based on a single-equivalent dipole representation of cardiac electrical activity and is suitable for patients with hemodynamically unstable VT. Imaging was performed in homogeneous and inhomogeneous saline-filled torso phantoms in which a catheter tip was guided toward a stationary electrical dipole source over distances of more than 5 cm. Using ISGA, the moving catheter tip was guided to within 0.61 +/-0.43 and 0.55 +/-0.39 mm of the stationary source in the homogeneous and inhomogeneous phantoms, respectively. This accuracy was achieved with less than ten movements of the catheter. These results suggest that ISGA has potential to provide accurate and efficient guidance for RFA procedures in the patient population with hemodynamically unstable arrhythmias.
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Affiliation(s)
- Maya E Barley
- Harvard-Massachusetts Institute of Technology Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139. USA.
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Shou G, Xia L, Jiang M, Wei Q, Liu F, Crozier S. Truncated total least squares: a new regularization method for the solution of ECG inverse problems. IEEE Trans Biomed Eng 2008; 55:1327-35. [PMID: 18390323 DOI: 10.1109/tbme.2007.912404] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The reconstruction of epicardial potentials (EPs) from body surface potentials (BSPs) can be characterized as an ill-posed inverse problem which generally requires a regularized numerical solution. Two kinds of errors/noise: geometric errors and measurement errors exist in the ECG inverse problem and make the solution of such problem more difficulty. In particular, geometric errors will directly affect the calculation of transfer matrix A in the linear system equation AX = B. In this paper, we have applied the truncated total least squares (TTLS) method to reconstruct EPs from BSPs. This method accounts for the noise/errors on both sides of the system equation and treats geometric errors in a new fashion. The algorithm is tested using a realistically shaped heart-lung-torso model with inhomogeneous conductivities. The h-adaptive boundary element method [h-BEM, a BEM mesh adaptation scheme which starts from preset meshes and then refines (adds/removes) grid with fixed order of interpolation function and prescribed numerical accuracy] is used for the forward modeling and the TTLS is applied for inverse solutions and its performance is also compared with conventional regularization approaches such as Tikhonov and truncated single value decomposition (TSVD) with zeroth-, first-, and second-order. The simulation results demonstrate that TTLS can obtain similar results in the situation of measurement noise only but performs better than Tikhonov and TSVD methods where geometric errors are involved, and that the zeroth-order regularization is the optimal choice for the ECG inverse problem. This investigation suggests that TTLS is able to robustly reconstruct EPs from BSPs and is a promising alternative method for the solution of ECG inverse problems.
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Affiliation(s)
- Guofa Shou
- Department of Biomedical Engineering, Zhejiang University, Hangzhou, China.
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