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Dasgupta S, Mah DY. Lead Management in Patients with Congenital Heart Disease. Card Electrophysiol Clin 2023; 15:481-491. [PMID: 37865521 DOI: 10.1016/j.ccep.2023.06.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2023]
Abstract
Pediatric patients with congenital heart disease present unique challenges when it comes to cardiac implantable electronic devices. Pacing strategy is often determined by patient size/weight and operator experience. Anatomic considerations, including residual shunts, anatomic obstructions and barriers, and abnormalities in the native conduction system, will affect the type of CIED implanted. Given the young age of patients, it is important to have an "eye on the future" when making pacemaker/defibrillator decisions, as one can expect several generator changes, lead revisions, and potential lead extractions during their lifetime.
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Affiliation(s)
- Soham Dasgupta
- Division of Pediatric Cardiology, Department of Pediatrics, Norton Children's Hospital, University of Louisville, 231 East Chestnut Street, Louisville, KY 40202, USA
| | - Douglas Y Mah
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA.
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2
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Qian S, Monaci S, Mendonca-Costa C, Campos F, Gemmell P, Zaidi HA, Rajani R, Whitaker J, Rinaldi CA, Bishop MJ. Additional coils mitigate elevated defibrillation threshold in right-sided implantable cardioverter defibrillator generator placement: a simulation study. Europace 2023; 25:euad146. [PMID: 37314196 PMCID: PMC10265967 DOI: 10.1093/europace/euad146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 05/13/2023] [Indexed: 06/15/2023] Open
Abstract
AIMS The standard implantable cardioverter defibrillator (ICD) generator (can) is placed in the left pectoral area; however, in certain circumstances, right-sided cans may be required which may increase defibrillation threshold (DFT) due to suboptimal shock vectors. We aim to quantitatively assess whether the potential increase in DFT of right-sided can configurations may be mitigated by alternate positioning of the right ventricular (RV) shocking coil or adding coils in the superior vena cava (SVC) and coronary sinus (CS). METHODS AND RESULTS A cohort of CT-derived torso models was used to assess DFT of ICD configurations with right-sided cans and alternate positioning of RV shock coils. Efficacy changes with additional coils in the SVC and CS were evaluated. A right-sided can with an apical RV shock coil significantly increased DFT compared to a left-sided can [19.5 (16.4, 27.1) J vs. 13.3 (11.7, 19.9) J, P < 0.001]. Septal positioning of the RV coil led to a further DFT increase when using a right-sided can [26.7 (18.1, 36.1) J vs. 19.5 (16.4, 27.1) J, P < 0.001], but not a left-sided can [12.1 (8.1, 17.6) J vs. 13.3 (11.7, 19.9) J, P = 0.099). Defibrillation threshold of a right-sided can with apical or septal coil was reduced the most by adding both SVC and CS coils [19.5 (16.4, 27.1) J vs. 6.6 (3.9, 9.9) J, P < 0.001, and 26.7 (18.1, 36.1) J vs. 12.1 (5.7, 13.5) J, P < 0.001]. CONCLUSION Right-sided, compared to left-sided, can positioning results in a 50% increase in DFT. For right-sided cans, apical shock coil positioning produces a lower DFT than septal positions. Elevated right-sided can DFTs may be mitigated by utilizing additional coils in SVC and CS.
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Affiliation(s)
- Shuang Qian
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Sofia Monaci
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Caroline Mendonca-Costa
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Fernando Campos
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Philip Gemmell
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Hassan A Zaidi
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
| | - Ronak Rajani
- Department of Cardiology, Guy’s and St Thomas’ Hospital, Westminster Bridge Rd, London SE1 7EH, UK
| | - John Whitaker
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
- Department of Cardiology, Guy’s and St Thomas’ Hospital, Westminster Bridge Rd, London SE1 7EH, UK
| | - Christopher A Rinaldi
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
- Department of Cardiology, Guy’s and St Thomas’ Hospital, Westminster Bridge Rd, London SE1 7EH, UK
| | - Martin J Bishop
- Department of Biomedical Engineering, School of Imaging Sciences and Biomedical Engineering, Kings College London, 4th North Wing, St Thomas’ Hospital, London SE1 7EH, UK
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3
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Mazumder O, Banerjee R, Roy D, Mukherjee A, Ghose A, Khandelwal S, Sinha A. Computational Model for Therapy Optimization of Wearable Cardioverter Defibrillator: Shockable Rhythm Detection and Optimal Electrotherapy. Front Physiol 2021; 12:787180. [PMID: 34955894 PMCID: PMC8703044 DOI: 10.3389/fphys.2021.787180] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/08/2021] [Indexed: 11/15/2022] Open
Abstract
Wearable cardioverter defibrillator (WCD) is a life saving, wearable, noninvasive therapeutic device that prevents fatal ventricular arrhythmic propagation that leads to sudden cardiac death (SCD). WCD are frequently prescribed to patients deemed to be at high arrhythmic risk but the underlying pathology is potentially reversible or to those who are awaiting an implantable cardioverter-defibrillator. WCD is programmed to detect appropriate arrhythmic events and generate high energy shock capable of depolarizing the myocardium and thus re-initiating the sinus rhythm. WCD guidelines dictate very high reliability and accuracy to deliver timely and optimal therapy. Computational model-based process validation can verify device performance and benchmark the device setting to suit personalized requirements. In this article, we present a computational pipeline for WCD validation, both in terms of shock classification and shock optimization. For classification, we propose a convolutional neural network-"Long Short Term Memory network (LSTM) full form" (Convolutional neural network- Long short term memory network (CNN-LSTM)) based deep neural architecture for classifying shockable rhythms like Ventricular Fibrillation (VF), Ventricular Tachycardia (VT) vs. other kinds of non-shockable rhythms. The proposed architecture has been evaluated on two open access ECG databases and the classification accuracy achieved is in adherence to American Heart Association standards for WCD. The computational model developed to study optimal electrotherapy response is an in-silico cardiac model integrating cardiac hemodynamics functionality and a 3D volume conductor model encompassing biophysical simulation to compute the effect of shock voltage on myocardial potential distribution. Defibrillation efficacy is simulated for different shocking electrode configurations to assess the best defibrillator outcome with minimal myocardial damage. While the biophysical simulation provides the field distribution through Finite Element Modeling during defibrillation, the hemodynamic module captures the changes in left ventricle functionality during an arrhythmic event. The developed computational model, apart from acting as a device validation test-bed, can also be used for the design and development of personalized WCD vests depending on subject-specific anatomy and pathology.
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4
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Qian S, Connolly A, Mendonca-Costa C, Campos F, Williams SE, Whitaker J, Rinaldi CA, Bishop MJ. An in-silico assessment of efficacy of two novel intra-cardiac electrode configurations versus traditional anti-tachycardia pacing therapy for terminating sustained ventricular tachycardia. Comput Biol Med 2021; 139:104987. [PMID: 34741904 PMCID: PMC8669079 DOI: 10.1016/j.compbiomed.2021.104987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 10/24/2021] [Accepted: 10/24/2021] [Indexed: 11/06/2022]
Abstract
The implanted cardioverter defibrillator (ICD) is an effective direct therapy for the treatment of cardiac arrhythmias, including ventricular tachycardia (VT). Anti-tachycardia pacing (ATP) is often applied by the ICD as the first mode of therapy, but is often found to be ineffective, particularly for fast VTs. In such cases, strong, painful and damaging backup defibrillation shocks are applied by the device. Here, we propose two novel electrode configurations: "bipolar" and "transmural" which both combine the concept of targeted shock delivery with the advantage of reduced energy required for VT termination. We perform an in silico study to evaluate the efficacy of VT termination by applying one single (low-energy) monophasic shock from each novel configuration, comparing with conventional ATP therapy. Both bipolar and transmural configurations are able to achieve a higher efficacy (93% and 85%) than ATP (45%), with energy delivered similar to and two orders of magnitudes smaller than conventional ICD defibrillation shocks, respectively. Specifically, the transmural configuration (which applies the shock vector directly across the scar substrate sustaining the VT) is most efficient, requiring typically less than 1 J shock energy to achieve a high efficacy. The efficacy of both bipolar and transmural configurations are higher when applied to slow VTs (100% and 97%) compared to fast VTs (57% and 29%). Both novel electrode configurations introduced are able to improve electrotherapy efficacy while reducing the overall number of required therapies and need for strong backup shocks.
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Affiliation(s)
- Shuang Qian
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom.
| | - Adam Connolly
- Invicro, Burlington Danes Building, Du Cane Rd, London, W12 0N, United Kingdom
| | - Caroline Mendonca-Costa
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
| | - Fernando Campos
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
| | - Steven E Williams
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
| | - John Whitaker
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom; Department of Cardiology, Guy's and St Thomas' Hospital, London, SE1 7EH, United Kingdom
| | - Christopher A Rinaldi
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom; Department of Cardiology, Guy's and St Thomas' Hospital, London, SE1 7EH, United Kingdom
| | - Martin J Bishop
- School of Biomedical Engineering and Imaging Sciences, Rayne Institute, King's College London, 4th Floor, Lambeth Wing, St. Thomas' Hospital, Westminster Bridge Road, London, SE1 7EH, United Kingdom
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5
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Prevalence, predictors and complications with defibrillation threshold testing in pediatric patients: Results from the NCDR. Int J Cardiol 2020; 305:44-49. [DOI: 10.1016/j.ijcard.2020.01.027] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/30/2019] [Accepted: 01/13/2020] [Indexed: 11/17/2022]
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6
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Pham TDN, Valente AM, Mayer JE, DeWitt ES, Mah DY. Implanted pacemaker and cardioverter-defibrillator in a patient with ectopia cordis. HeartRhythm Case Rep 2020; 6:110-113. [PMID: 32099802 PMCID: PMC7026567 DOI: 10.1016/j.hrcr.2019.11.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Affiliation(s)
- Tam Dan N Pham
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Anne-Marie Valente
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - John E Mayer
- Department of Cardiovascular Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Elizabeth S DeWitt
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Douglas Y Mah
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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7
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Tate JD, Pilcher TA, Aras KK, Burton BM, MacLeod RS. Validating defibrillation simulation in a human-shaped phantom. Heart Rhythm 2019; 17:661-668. [PMID: 31765807 DOI: 10.1016/j.hrthm.2019.11.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Indexed: 01/23/2023]
Abstract
BACKGROUND We previously developed a computational model to aid clinicians in positioning implantable cardioverter-defibrillators (ICDs), especially in the case of abnormal anatomies that commonly arise in pediatric cases. We have validated the model clinically on the body surface; however, validation within the volume of the heart is required to establish complete confidence in the model and improve its use in clinical settings. OBJECTIVE The goal of this study was to use an animal model and thoracic phantom to record the ICD potential field within the heart and on the torso to validate our defibrillation simulation system. METHODS We recorded defibrillator shock potentials from an ICD suspended together with an animal heart in a human-shaped torso tank and compared them with simulated values. We also compared the scaled distribution threshold, an analog to the defibrillation threshold, calculated from the measured and simulated electric fields within the myocardium. RESULTS ICD potentials recorded on the tank and cardiac surface and within the myocardium agreed well with those predicted by the simulation. A quantitative comparison of the recorded and simulated potentials yielded a mean correlation of 0.94 and a relative error of 19.1%. The simulation can also predict scaled distribution thresholds similar to those calculated from the measured potential fields. CONCLUSION We found that our simulation could predict potential fields with high correlation with the measured values within the heart and on the torso surface. These results support the use of this model for the optimization of ICD placements.
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Affiliation(s)
- Jess D Tate
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah.
| | - Thomas A Pilcher
- Division of Pediatric Cardiology, University of Utah, Salt Lake City, Utah
| | - Kedar K Aras
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Brett M Burton
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
| | - Rob S MacLeod
- Department of Biomedical Engineering, University of Utah, Salt Lake City, Utah; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, Utah
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8
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Plancke AM, Connolly A, Gemmell PM, Neic A, McSpadden LC, Whitaker J, O'Neill M, Rinaldi CA, Rajani R, Niederer SA, Plank G, Bishop MJ. Generation of a cohort of whole-torso cardiac models for assessing the utility of a novel computed shock vector efficiency metric for ICD optimisation. Comput Biol Med 2019; 112:103368. [PMID: 31352217 PMCID: PMC6873640 DOI: 10.1016/j.compbiomed.2019.103368] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/22/2019] [Accepted: 07/22/2019] [Indexed: 11/29/2022]
Abstract
Implanted cardiac defibrillators (ICDs) seek to automatically detect and terminate potentially lethal ventricular arrhythmias by applying strong internal electric shocks across the heart. However, the optimisation of the specific electrode design and configurations represents an intensive area of research in the pursuit of reduced shock strengths and fewer device complications and risks. Computational whole-torso simulations play an important role in this endeavour, although knowing which specific metric should be used to assess configuration efficacy and assessing the impact of different patient anatomies and pathologies, and the corresponding effect this may have on different metrics has not been investigated. We constructed a cohort of CT-derived high-resolution whole torso-cardiac computational models, including variants of cardiomyopathies and patients with differing torso dimensions. Simulations of electric shock application between electrode configurations corresponding to transveneous (TV-ICD) and subcutaneous (S-ICD) ICDs were modelled and conventional metrics such as defibrillation threshold (DFT) and impedance computed. In addition, we computed a novel metric termed the shock vector efficiency (η), which quantifies the fraction of electrical energy dissipated in the heart relative to the rest of the torso. Across the cohort, S-ICD configurations showed higher DFTs and impedances than TV-ICDs, as expected, although little consistent difference was seen between healthy and cardiomyopathy variants. η was consistently <2% for S-ICD configurations, becoming as high as 13% for TV-ICD setups. Simulations also suggested that a total torso height of approximately 20 cm is required for convergence in η. Overall, η was seen to be approximately negatively correlated with both DFT and impedance. However, important scenarios were identified in which certain values of DFT (or impedance) were associated with a range of η values, and vice-versa, highlighting the heterogeneity introduced by the different torsos and pathologies modelled. In conclusion, the shock vector efficiency represents a useful additional metric to be considered alongside DFT and impedance in the optimisation of ICD electrode configurations, particularly in the context of differing torso anatomies and cardiac pathologies, which can induce significant heterogeneity in conventional metrics of ICD efficacy.
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Affiliation(s)
- Anne-Marie Plancke
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Adam Connolly
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Philip M Gemmell
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Aurel Neic
- Institute of Biophysics, Medical University of Graz, Austria
| | | | - John Whitaker
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Cardiology, Guy's and St Thomas' Hospitals, London, UK
| | - Mark O'Neill
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Cardiology, Guy's and St Thomas' Hospitals, London, UK
| | - Christopher A Rinaldi
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK; Department of Cardiology, Guy's and St Thomas' Hospitals, London, UK
| | - Ronak Rajani
- Cardiovascular Imaging Department, St Thomas' Hospital, London, UK
| | - Steven A Niederer
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK
| | - Gernot Plank
- Institute of Biophysics, Medical University of Graz, Austria
| | - Martin J Bishop
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging Sciences, King's College London, London, UK.
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Tate J, Stinstra J, Pilcher T, Poursaid A, Jolley MA, Saarel E, Triedman J, MacLeod RS. Measuring defibrillator surface potentials: The validation of a predictive defibrillation computer model. Comput Biol Med 2018; 102:402-410. [PMID: 30195579 DOI: 10.1016/j.compbiomed.2018.08.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/24/2018] [Accepted: 08/24/2018] [Indexed: 01/26/2023]
Abstract
Implantable cardioverter defibrillators (ICDs) are commonly used to reduce the risk in patients with life-threatening arrhythmias, however, clinicians have little systematic guidance to place the device, especially in cases of unusual anatomy. We have previously developed a computational model that evaluates the efficacy of a delivered shock as a clinical and research aid to guide ICD placement on a patient specific basis. We report here on progress to validate this model with measured ICD surface potential maps from patients undergoing ICD implantation and testing for defibrillation threshold (DFT). We obtained body surface potential maps of the defibrillation pulses by adapting a limited lead selection and potential estimation algorithm to deal with the limited space for recording electrodes. Comparison of the simulated and measured potential maps of the defibrillation shock yielded similar patterns, a typical correlation greater than 0.9, and a relative error less than 15%. Comparison of defibrillation thresholds also showed accurate prediction of the simulations. The high agreement of the potential maps and DFTs suggests that the predictive simulation generates realistic potential values and can accurately predict DFTs in patients. These validation results pave the way for use of this model in optimization studies prior to device implantation.
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Affiliation(s)
- Jess Tate
- Department of Bioengineering, University of Utah, Salt Lake City, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, USA.
| | - Jeroen Stinstra
- Department of Bioengineering, University of Utah, Salt Lake City, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, USA
| | - Thomas Pilcher
- Division of Pediatric Cardiology, University of Utah, Salt Lake City, USA
| | - Ahrash Poursaid
- Department of Bioengineering, University of Utah, Salt Lake City, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, USA
| | - Matthew A Jolley
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, USA
| | - Elizabeth Saarel
- Division of Pediatric Cardiology, University of Utah, Salt Lake City, USA
| | - John Triedman
- Department of Cardiology, Children's Hospital Boston, Boston, Massachusetts, USA
| | - Rob S MacLeod
- Department of Bioengineering, University of Utah, Salt Lake City, USA; Scientific Computing and Imaging Institute, University of Utah, Salt Lake City, USA
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10
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Kriebel T, Müller MJ, Ruschewski W, Krause U, Paul T, Schneider H. Value of Regular Defibrillation Threshold Testing After Extracardiac Implantable Cardioverter Defibrillator Placement in Small Children During Mid-Term Follow-Up. JACC Clin Electrophysiol 2018; 4:936-943. [PMID: 30025695 DOI: 10.1016/j.jacep.2018.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 03/05/2018] [Accepted: 03/15/2018] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The purpose of this study was to analyze course of defibrillation threshold (DFT) with growth. BACKGROUND Data on regular DFT testing after extracardiac implantable cardioverter-defibrillator (ICD) placement in infants and small children is still limited. METHODS An extracardiac ICD was placed in 23 pediatric patients (median age 6.1 years; median body weight 21 kg, median length 120 cm). The defibrillator lead was tunneled pleurally, and the device was placed as "active can" in the right upper abdomen or in a horizontal position between the diaphragm and the pericardium, respectively. DFT was verified intraoperatively, 3 months later, and every 12 months thereafter. The aim was to achieve DFT <15 J allowing ICD programming with a double safety margin above DFT. RESULTS In all 23 patients, an intraoperative DFT <15 J could be accomplished. Serial DFT testing showed an increase from a median DFT of 10 J intraoperatively to 15 J after 1 year. During mean follow-up of 2.0 years, a significant correlation between DFT and body length, but not body weight, was observed. In 4 of 23 (17%) patients, surgical revision was required because of a DFT increase >20 J during regular DFT testing. No complications regarding DFT testing were noted. CONCLUSIONS After extracardiac ICD placement in infants and small children, DFT increase related to body length was evident during mid-term follow-up. Routine serial DFT testing was a safe procedure and identified a significant DFT increase in 4 of 23 patients. Serial DFT testing during follow-up in these patients is recommended.
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Affiliation(s)
- Thomas Kriebel
- Department of Pediatric Cardiology and Intensive Care Medicine, George August University Medical Center, Göttingen, Germany.
| | - Matthias J Müller
- Department of Pediatric Cardiology and Intensive Care Medicine, George August University Medical Center, Göttingen, Germany
| | - Wolfgang Ruschewski
- Department of Thoracic and Cardiovascular Surgery, Georg August University Medical Center, Göttingen, Germany
| | - Ulrich Krause
- Department of Pediatric Cardiology and Intensive Care Medicine, George August University Medical Center, Göttingen, Germany
| | - Thomas Paul
- Department of Pediatric Cardiology and Intensive Care Medicine, George August University Medical Center, Göttingen, Germany
| | - Heike Schneider
- Department of Pediatric Cardiology and Intensive Care Medicine, George August University Medical Center, Göttingen, Germany
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11
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Qian L, Wang J, Jin L, Song B, Wu X. Effect of ventricular myocardium characteristics on the defibrillation threshold. Technol Health Care 2018; 26:241-248. [PMID: 29710752 PMCID: PMC6004974 DOI: 10.3233/thc-174599] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Myocardium characteristics differ markedly among individuals and play an important role in defibrillation threshold. The accuracy of simulation models used in most published studies are still have room to be improved and most of them only discussed the effect of myocardial anisotropy on defibrillation threshold. In our manuscript, a rabbit ventricular finite-element (FE) volume conductor model with high precision was constructed. Ventricular myocardium characteristics include cardiomyocyte coupling and the degree of myocardial anisotropy, which are represented as the value and the ratio of anisotropic conductivity, respectively. Quantitative analysis was performed simultaneously in terms of cardiomyocyte coupling and the degree of myocardial anisotropy. Based on this, the combined effects of these two factors were further discussed. The electric field distributions of shocks and the defibrillation thresholds under different myocardial characteristics were simulated on this model. The simulation results revealed that as the degree of myocardial anisotropy increases, defibrillation threshold increases, and cardiomyocyte decoupling (decrease in electrical conductivity) can considerably increase the defibrillation threshold.
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Affiliation(s)
- Li Qian
- Electrical Engineering Department, Fudan University, Shanghai, China
| | - Jianfei Wang
- Electrical Engineering Department, Fudan University, Shanghai, China
| | - Lian Jin
- Electrical Engineering Department, Fudan University, Shanghai, China
| | - Biao Song
- Electrical Engineering Department, Fudan University, Shanghai, China
| | - Xiaomei Wu
- Electrical Engineering Department, Fudan University, Shanghai, China.,Shanghai Engineering Research Center of Assistive Devices, The Key Laboratory of Medical Imaging Computing, Shanghai, China.,Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai, China
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12
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Connolly A, Robson MD, Schneider J, Burton R, Plank G, Bishop MJ. Highly trabeculated structure of the human endocardium underlies asymmetrical response to low-energy monophasic shocks. CHAOS (WOODBURY, N.Y.) 2017; 27:093913. [PMID: 28964115 PMCID: PMC5570597 DOI: 10.1063/1.4999609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 08/03/2017] [Indexed: 06/07/2023]
Abstract
Novel low-energy defibrillation therapies are thought to be driven by virtual-electrodes (VEs), due to the interaction of applied monophasic electric shocks with fine-scale anatomical structures within the heart. Significant inter-species differences in the cardiac (micro)-anatomy exist, however, particularly with respect to the degree of endocardial trabeculations, which may underlie important differences in response to low-energy defibrillation protocols. Understanding the interaction of monophasic electric fields with the specific human micro-anatomy is therefore imperative in facilitating the translation and optimisation of these promising experimental therapies to the clinic. In this study, we sought to investigate how electric fields from implanted devices interact with the highly trabeculated human endocardial surface to better understand shock success in order to help optimise future clinical protocols. A bi-ventricular human computational model was constructed from high resolution (350 μm) ex-vivo MR data, including anatomically accurate endocardial structures. Monophasic shocks were applied between a basal right ventricular catheter and an exterior ground. Shocks of varying strengths were applied with both anodal [positive right ventricle (RV) electrode] and cathodal (negative RV electrode) polarities at different states of tissue refractoriness and during induced arrhythmias. Anodal shocks induced isolated positive VEs at the distal side of "detached" trabeculations, which rapidly spread into hyperpolarised tissue on the surrounding endocardial surfaces following the shock. Anodal shocks thus depolarised more tissue 10 ms after the shock than cathodal shocks where the propagation of activation from VEs induced on the proximal side of "detached" trabeculations was prevented due to refractory endocardium. Anodal shocks increased arrhythmia complexity more than cathodal shocks during failed anti-arrhythmia shocks. In conclusion, multiple detached trabeculations in the human ventricle interact with anodal stimuli to induce multiple secondary sources from VEs, facilitating more rapid shock-induced ventricular excitation compared to cathodal shocks. Such a mechanism may help explain inter-species differences in response to shocks and help to develop novel defibrillation strategies.
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Affiliation(s)
- Adam Connolly
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
| | - Matthew D Robson
- Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
| | - Jürgen Schneider
- Division of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom
| | - Rebecca Burton
- Pharmacology Department, University of Oxford, Oxford, United Kingdom
| | - Gernot Plank
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - Martin J Bishop
- Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom
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Connolly AJ, Vigmond E, Bishop MJ. Bidomain Predictions of Virtual Electrode-Induced Make and Break Excitations around Blood Vessels. Front Bioeng Biotechnol 2017; 5:18. [PMID: 28396856 PMCID: PMC5366349 DOI: 10.3389/fbioe.2017.00018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/02/2017] [Indexed: 11/16/2022] Open
Abstract
Introduction and background Virtual electrodes formed by field stimulation during defibrillation of cardiac tissue play an important role in eliciting activations. It has been suggested that the coronary vasculature is an important source of virtual electrodes, especially during low-energy defibrillation. This work aims to further the understanding of how virtual electrodes from the coronary vasculature influence defibrillation outcomes. Methods Using the bidomain model, we investigated how field stimulation elicited activations from virtual electrodes around idealized intramural blood vessels. Strength–interval curves, which quantify the stimulus strength required to elicit wavefront propagation from the vessels at different states of tissue refractoriness, were computed for each idealized geometry. Results Make excitations occurred at late diastolic intervals, originating from regions of depolarization around the vessel. Break excitations occurred at early diastolic intervals, whereby the vessels were able to excite surrounding refractory tissue due to the local restoration of excitability by virtual electrode-induced hyperpolarizations. Overall, strength–interval curves had similar morphologies and underlying excitation mechanisms compared with previous experimental and numerical unipolar stimulation studies of cardiac tissue. Including the presence of the vessel wall increased the field strength required for make excitations but decreased the field strength required for break excitations, and the field strength at which break excitations occurred was generally greater than 5 V/cm. Finally, in a more realistic ventricular slice geometry, the proximity of virtual electrodes around subepicardial vessels was seen to cause break excitations in the form of propagating unstable wavelets to the subepicardial layer. Conclusion Representing the blood vessel wall microstructure in computational bidomain models of defibrillation is recommended as it significantly alters the electrophysiological response of the vessel to field stimulation. Although vessels may facilitate excitation of relatively refractory tissue via break excitations, the field strength required for this is generally greater than those used in the literature on low-energy defibrillation. However, the high-intensity shocks used in standard defibrillation may elicit break excitation propagation from the coronary vasculature.
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Affiliation(s)
- Adam J Connolly
- Department of Biomedical Engineering and Imaging Sciences, King's College London , London , UK
| | - Edward Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Instituté, Fondation Bordeaux Université, Bordeaux, France; IMB, UMR 5251, Univ. Bordeaux, Talence, France
| | - Martin J Bishop
- Department of Biomedical Engineering and Imaging Sciences, King's College London , London , UK
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Low-energy defibrillation research using a rabbit ventricular model: optimizing the potential gradient distribution using multiple epicardial electrodes. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:2753-2756. [PMID: 28268889 DOI: 10.1109/embc.2016.7591300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Cardiac potential gradient distribution directly affects defibrillation efficacy, and the electrode configuration that ensures optimal distribution is yet to be determined. In this study, a rabbit ventricular finite element conductor model containing blood perfusion in ventricular cavities was developed. The electric field was solved on the model by using 95% myocardial volume potential gradient higher than 5 V/cm as the successful defibrillation threshold (DFT). Multiple epicardial electrodes (MEE) protocols and a SCAN protocol were used to identify the optimum defibrillation method. Results showed that when using the SCAN protocol, DFT energy reduced to 4.3% that of the control group which had the traditional implantable cardioverter defibrillator current path. Rapidly switching scanning stimuli generated using MEE pairs is a promising low-energy defibrillation method. For multiple electrodes defibrillation, the distribution of the electrode pairs determine the defibrillation efficacy, and the counteraction effect has negative effect on defibrillation. These findings can provide suggestions for clinical applications.
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Connolly A, Vigmond E, Bishop M. Virtual electrodes around anatomical structures and their roles in defibrillation. PLoS One 2017; 12:e0173324. [PMID: 28253365 PMCID: PMC5333918 DOI: 10.1371/journal.pone.0173324] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 02/17/2017] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Virtual electrodes from structural/conductivity heterogeneities are known to elicit wavefront propagation, upon field-stimulation, and are thought to be important for defibrillation. In this work we investigate how the constitutive and geometrical parameters associated with such anatomical heterogeneities, represented by endo/epicardial surfaces and intramural surfaces in the form of blood-vessels, affect the virtual electrode patterns produced. METHODS AND RESULTS The steady-state bidomain model is used to obtain, using analytical and numerical methods, the virtual electrode patterns created around idealized endocardial trabeculations and blood-vessels. The virtual electrode pattern around blood-vessels is shown to be composed of two dominant effects; current traversing the vessel surface and conductivity heterogeneity from the fibre-architecture. The relative magnitudes of these two effects explain the swapping of the virtual electrode polarity observed, as a function of the vessel radius, and aid in the understanding of the virtual electrode patterns predicted by numerical bidomain modelling. The relatively high conductivity of blood, compared to myocardium, is shown to cause stronger depolarizations in the endocardial trabeculae grooves than the protrusions. CONCLUSIONS The results provide additional quantitative understanding of the virtual electrodes produced by small-scale ventricular anatomy, and highlight the importance of faithfully representing the physiology and the physics in the context of computational modelling of field stimulation.
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Affiliation(s)
- Adam Connolly
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, St. Thomas’ Hospital, London, United Kingdom
| | - Edward Vigmond
- IHU Liryc, Electrophysiology and Heart Modeling Instituté, fondation Bordeaux Université, F-33600 Pessac-Bordeaux, France
- Univ. Bordeaux, IMB, UMR 5251, F-33400 Talence, France
| | - Martin Bishop
- Division of Imaging Sciences and Biomedical Engineering, King’s College London, St. Thomas’ Hospital, London, United Kingdom
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Gillette K, Tate J, Kindall B, Good W, Wilkinson J, Simha N, MacLeod R. Temporal Dilation of Animal Cardiac Recordings Registered to Human Torso Geometries. COMPUTING IN CARDIOLOGY 2016; 43:329-332. [PMID: 28451593 PMCID: PMC5404704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recordings of cardiac surface potentials from animal hearts can be mapped into human torso and used as source potentials for torso simulation. However, geometric registration of the heart can introduce changes in the effective conduction velocity due to change in relative positions of the recording sites. We developed a time dilation technique to ensure that adjusted cardiac potential recordings had physiological timing similar to human recordings after registration and corrected for conduction velocity. Temporal dilation was performed both linearly and nonlinearly using two scaling techniques that reflect either global or local deformations. Linear temporal dilation of canine epicardial potential recordings using global scaling could be used to generate electrograms physiologically similar to humans in terms of conduction velocity, activation recovery interval, total activation time, and activation maps. Epicardial potential mapping of such dilated canine recordings thus allows the investigation of human-like arrhythmias and other disease states that can not be readily induced or measured in humans.
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Affiliation(s)
- Karli Gillette
- SCI Institute, University of Utah, Salt Lake City, Utah, USA
| | - Jess Tate
- SCI Institute, University of Utah, Salt Lake City, Utah, USA
| | - Brianna Kindall
- SCI Institute, University of Utah, Salt Lake City, Utah, USA
| | - Wilson Good
- SCI Institute, University of Utah, Salt Lake City, Utah, USA
| | | | | | - Rob MacLeod
- SCI Institute, University of Utah, Salt Lake City, Utah, USA
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BAYSA SHERRIEJOYA, OLEN MELISSA, KANTER RONALDJ, FISHBERGER STEVENB. Defibrillation Testing Strategies of Pediatric and Adult Congenital Electrophysiologists during ICD Implantation. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2016; 39:843-7. [DOI: 10.1111/pace.12896] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/11/2016] [Accepted: 05/20/2016] [Indexed: 11/28/2022]
Affiliation(s)
- SHERRIE JOY A. BAYSA
- Nicklaus Children's Hospital Heart Program; Miami Children's Health System; Miami Florida
| | - MELISSA OLEN
- Nicklaus Children's Hospital Heart Program; Miami Children's Health System; Miami Florida
| | - RONALD J. KANTER
- Nicklaus Children's Hospital Heart Program; Miami Children's Health System; Miami Florida
| | - STEVEN B. FISHBERGER
- Nicklaus Children's Hospital Heart Program; Miami Children's Health System; Miami Florida
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Noro M, Zhu X, Enomoto Y, Oikawa Y, Tatsunami H, Ishii R, Toyoda Y, Asami M, Sahara N, Takagi T, Narabayashi Y, Hashimoto H, Ito N, Kujime S, Sakai T, Nakamura K, Sakata T, Abe H, Sugi K. Decreased Defibrillation Threshold and Minimized Myocardial Damage With Left Axilla Implantable Cardioverter Defibrillator Implantation. Circ J 2016; 80:878-86. [PMID: 26888267 DOI: 10.1253/circj.cj-15-1258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND To reduce myocardial damage caused by implantable cardioverter defibrillator (ICD) shock, the left axilla was studied as an alternative pulse generator implantation site, and compared with the traditional implantation site, the left anterior chest. METHODS AND RESULTS Computer simulation was used to study the defibrillation conduction pattern and estimate the simulated defibrillation threshold (DFT) and myocardial damage when pulse generators were placed in the left axilla and left anterior chest, respectively; pulse generators were also newly implanted in the left axilla (n=30) and anterior chest (n=40) to compare the corresponding DFT. On simulation, when ICD generators were implanted in the left axilla, compared with the left anterior chest, the whole heart may be defibrillated with a lower defibrillation energy (left axilla 6.4 J vs. left anterior chest 12.0 J) and thus the proportion of cardiac myocardial damage may be reduced (2.1 vs. 4.2%). Clinically, ventricular fibrillation was successfully terminated with a defibrillation output ≤5 J in 86.7% (26/30) of the left axillary group, and in 27.5% (11/40) of the left anterior group (P<0.001). CONCLUSIONS Clinically and theoretically, the left axilla was shown to be an improved ICD implantation site that may reduce DFT and lessen myocardial damage due to shock. Lower DFT also facilitates less myocardial damage, as a result of the lower shock required.
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Affiliation(s)
- Mahito Noro
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
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19
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Trayanova NA, Chang KC. How computer simulations of the human heart can improve anti-arrhythmia therapy. J Physiol 2016; 594:2483-502. [PMID: 26621489 DOI: 10.1113/jp270532] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2015] [Accepted: 11/25/2015] [Indexed: 01/26/2023] Open
Abstract
Over the last decade, the state-of-the-art in cardiac computational modelling has progressed rapidly. The electrophysiological function of the heart can now be simulated with a high degree of detail and accuracy, opening the doors for simulation-guided approaches to anti-arrhythmic drug development and patient-specific therapeutic interventions. In this review, we outline the basic methodology for cardiac modelling, which has been developed and validated over decades of research. In addition, we present several recent examples of how computational models of the human heart have been used to address current clinical problems in cardiac electrophysiology. We will explore the use of simulations to improve anti-arrhythmic pacing and defibrillation interventions; to predict optimal sites for clinical ablation procedures; and to aid in the understanding and selection of arrhythmia risk markers. Together, these studies illustrate how the tremendous advances in cardiac modelling are poised to revolutionize medical treatment and prevention of arrhythmia.
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Affiliation(s)
- Natalia A Trayanova
- Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA.,Johns Hopkins University, Baltimore, MD, 21218, USA
| | - Kelly C Chang
- Johns Hopkins School of Medicine, Baltimore, MD, 21205, USA
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20
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Noro M, Zhu X, Enomoto Y, Asami M, Ishii R, Toyoda Y, Sahara N, Takagi T, Narabayasi Y, Hashimoto H, Ito N, Kujime S, Oikawa Y, Tatsunami H, Sakai T, Nakamura K, Sakata T, Sugi K. Efficacy and Myocardial Injury With Subcutaneous Implantable Cardioverter Defibrillators – Computer Simulation of Defibrillation Shock Conduction –. Circ J 2016; 80:85-92. [DOI: 10.1253/circj.cj-15-0883] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mahito Noro
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Xin Zhu
- Biomedical Information Technology Lab, University of Aizu
| | - Yoshinari Enomoto
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Masako Asami
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Rina Ishii
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Yasutake Toyoda
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Naohiko Sahara
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Takahito Takagi
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Yuriko Narabayasi
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Hikari Hashimoto
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Naoshi Ito
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Shingo Kujime
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | | | | | - Tsuyoshi Sakai
- Division of Cardiovascular Medicine, Saiseikai Yokohama Eastern Hospital
| | - Keijirou Nakamura
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Takao Sakata
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
| | - Kaoru Sugi
- Division of Cardiovascular Medicine, Toho University Ohashi Medical Center
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Lim TSE, Tan BY, Ho KL, Lim CYP, Teo WS, Ching CK. Initial experience of subcutaneous implantable cardioverter defibrillators in Singapore: a case series and review of the literature. Singapore Med J 2015; 56:580-5. [PMID: 26512151 DOI: 10.11622/smedj.2015154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Transvenous implantable cardioverter defibrillators are a type of implantable cardiac device. They are effective at reducing total and arrhythmic mortality in patients at risk of sudden cardiac death. Subcutaneous implantable cardioverter defibrillators (S-ICDs) are a new alternative that avoids the disadvantages of transvenous lead placement. In this case series, we report on the initial feasibility and safety of S-ICD implantation in Singapore.
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Affiliation(s)
| | - Boon Yew Tan
- Department of Cardiology, National Heart Centre, Singapore
| | - Kah Leng Ho
- Department of Cardiology, National Heart Centre, Singapore
| | | | - Wee Siong Teo
- Department of Cardiology, National Heart Centre, Singapore
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22
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Gillette K, Tate J, Kindall B, Van Dam P, Kholmovski E, MacLeod R. Generation of Combined-Modality Tetrahedral Meshes. COMPUTING IN CARDIOLOGY 2015; 2015:953-956. [PMID: 27088101 PMCID: PMC4830507 DOI: 10.1109/cic.2015.7411070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Registering and combining anatomical components from different image modalities, like MRI and CT that have different tissue contrast, could result in patient-specific models that more closely represent underlying anatomical structures. In this study, we combined a pair of CT and MRI scans of a pig thorax to make a tetrahedral mesh and compared different registration techniques including rigid, affine, thin plate spline morphing (TPSM), and iterative closest point (ICP), to superimpose the segmented bones from the CT scan on the soft tissues segmented from the MRI. The TPSM and affine-registered bones remained close to, but not overlapping, important soft tissue. Simulation models, including an ECG forward model and a defibrillation model, were computed on generated multi-modality meshes after TPSM and affine registration and compared to those based on the original torso mesh.
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Affiliation(s)
- Karli Gillette
- University of Utah, Salt Lake City, Utah, United States of America
| | - Jess Tate
- University of Utah, Salt Lake City, Utah, United States of America
| | - Brianna Kindall
- University of Utah, Salt Lake City, Utah, United States of America
| | - Peter Van Dam
- Radbound University Medical Center, Nijmegen, Netherlands
| | | | - Robert MacLeod
- University of Utah, Salt Lake City, Utah, United States of America
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23
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Sodhi SS, Cedars AM. Primary Prevention of Sudden Cardiac Death in Adults with Transposition of the Great Arteries: A Review of Implantable Cardioverter-Defibrillator Placement. Tex Heart Inst J 2015; 42:309-18. [PMID: 26413012 DOI: 10.14503/thij-14-4352] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Transposition of the great arteries encompasses a set of structural congenital cardiac lesions that has in common ventriculoarterial discordance. Primarily because of advances in medical and surgical care, an increasing number of children born with this anomaly are surviving into adulthood. Depending upon the subtype of lesion or the particular corrective surgery that the patient might have undergone, this group of adult congenital heart disease patients constitutes a relatively new population with unique medical sequelae. Among the more common and difficult to manage are cardiac arrhythmias and other sequelae that can lead to sudden cardiac death. To date, the question of whether implantable cardioverter-defibrillators should be placed in this cohort as a preventive measure to abort sudden death has largely gone unanswered. Therefore, we review the available literature surrounding this issue.
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Khairy P, Van Hare GF, Balaji S, Berul CI, Cecchin F, Cohen MI, Daniels CJ, Deal BJ, Dearani JA, Groot ND, Dubin AM, Harris L, Janousek J, Kanter RJ, Karpawich PP, Perry JC, Seslar SP, Shah MJ, Silka MJ, Triedman JK, Walsh EP, Warnes CA. PACES/HRS expert consensus statement on the recognition and management of arrhythmias in adult congenital heart disease: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the International Society for Adult Congenital Heart Disease (ISACHD). Can J Cardiol 2014; 30:e1-e63. [PMID: 25262867 DOI: 10.1016/j.cjca.2014.09.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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25
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Images as drivers of progress in cardiac computational modelling. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2014; 115:198-212. [PMID: 25117497 PMCID: PMC4210662 DOI: 10.1016/j.pbiomolbio.2014.08.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Accepted: 08/02/2014] [Indexed: 11/28/2022]
Abstract
Computational models have become a fundamental tool in cardiac research. Models are evolving to cover multiple scales and physical mechanisms. They are moving towards mechanistic descriptions of personalised structure and function, including effects of natural variability. These developments are underpinned to a large extent by advances in imaging technologies. This article reviews how novel imaging technologies, or the innovative use and extension of established ones, integrate with computational models and drive novel insights into cardiac biophysics. In terms of structural characterization, we discuss how imaging is allowing a wide range of scales to be considered, from cellular levels to whole organs. We analyse how the evolution from structural to functional imaging is opening new avenues for computational models, and in this respect we review methods for measurement of electrical activity, mechanics and flow. Finally, we consider ways in which combined imaging and modelling research is likely to continue advancing cardiac research, and identify some of the main challenges that remain to be solved.
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Khairy P, Van Hare GF, Balaji S, Berul CI, Cecchin F, Cohen MI, Daniels CJ, Deal BJ, Dearani JA, Groot ND, Dubin AM, Harris L, Janousek J, Kanter RJ, Karpawich PP, Perry JC, Seslar SP, Shah MJ, Silka MJ, Triedman JK, Walsh EP, Warnes CA. PACES/HRS Expert Consensus Statement on the Recognition and Management of Arrhythmias in Adult Congenital Heart Disease: developed in partnership between the Pediatric and Congenital Electrophysiology Society (PACES) and the Heart Rhythm Society (HRS). Endorsed by the governing bodies of PACES, HRS, the American College of Cardiology (ACC), the American Heart Association (AHA), the European Heart Rhythm Association (EHRA), the Canadian Heart Rhythm Society (CHRS), and the International Society for Adult Congenital Heart Disease (ISACHD). Heart Rhythm 2014; 11:e102-65. [PMID: 24814377 DOI: 10.1016/j.hrthm.2014.05.009] [Citation(s) in RCA: 380] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Indexed: 02/07/2023]
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Trayanova NA. Virtual 3D heart models to aid pacemaker implantation in children. Future Cardiol 2013; 10:5-8. [PMID: 24344653 DOI: 10.2217/fca.13.94] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Affiliation(s)
- Natalia A Trayanova
- Department of Biomedical Engineering & Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA.
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28
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Chamakuri N, Kunisch K, Plank G. On boundary stimulation and optimal boundary control of the bidomain equations. Math Biosci 2013; 245:206-15. [PMID: 23856647 DOI: 10.1016/j.mbs.2013.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 07/02/2013] [Accepted: 07/04/2013] [Indexed: 11/30/2022]
Abstract
The bidomain equations with Neumann boundary stimulation and optimal control of these stimuli are investigated. First an analytical framework for boundary control is provided. Then a parallel finite element based algorithm is devised and its efficiency is demonstrated not only for the direct problem but also for the optimal control problem. The computations realize a model configuration corresponding to optimal boundary defibrillation of a reentry phenomenon by applying current density stimuli.
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Affiliation(s)
- Nagaiah Chamakuri
- Radon Institute for Computational and Applied Mathematics, Altenbergerstr. 69, Linz A-4040, Austria.
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29
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Escudero C, Khairy P, Sanatani S. Electrophysiologic Considerations in Congenital Heart Disease and Their Relationship to Heart Failure. Can J Cardiol 2013; 29:821-9. [DOI: 10.1016/j.cjca.2013.02.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 02/14/2013] [Accepted: 02/20/2013] [Indexed: 10/26/2022] Open
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30
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Rantner LJ, Vadakkumpadan F, Spevak PJ, Crosson JE, Trayanova NA. Placement of implantable cardioverter-defibrillators in paediatric and congenital heart defect patients: a pipeline for model generation and simulation prediction of optimal configurations. J Physiol 2013; 591:4321-34. [PMID: 23798492 DOI: 10.1113/jphysiol.2013.255109] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
There is currently no reliable way of predicting the optimal implantable cardioverter-defibrillator (ICD) placement in paediatric and congenital heart defect (CHD) patients. This study aimed to: (1) develop a new image processing pipeline for constructing patient-specific heart-torso models from clinical magnetic resonance images (MRIs); (2) use the pipeline to determine the optimal ICD configuration in a paediatric tricuspid valve atresia patient; (3) establish whether the widely used criterion of shock-induced extracellular potential (Φe) gradients ≥5 V cm(-1) in ≥95% of ventricular volume predicts defibrillation success. A biophysically detailed heart-torso model was generated from patient MRIs. Because transvenous access was impossible, three subcutaneous and three epicardial lead placement sites were identified along with five ICD scan locations. Ventricular fibrillation was induced, and defibrillation shocks were applied from 11 ICD configurations to determine defibrillation thresholds (DFTs). Two configurations with epicardial leads resulted in the lowest DFTs overall and were thus considered optimal. Three configurations shared the lowest DFT among subcutaneous lead ICDs. The Φe gradient criterion was an inadequate predictor of defibrillation success, as defibrillation failed in numerous instances even when 100% of the myocardium experienced such gradients. In conclusion, we have developed a new image processing pipeline and applied it to a CHD patient to construct the first active heart-torso model from clinical MRIs.
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Affiliation(s)
- Lukas J Rantner
- N. A. Trayanova: Johns Hopkins University, 3400 N Charles St., 216 Hackerman Hall, Baltimore, MD 21218, USA.
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Frangi AF, Hose DR, Hunter PJ, Ayache N, Brooks D. Special issue on medical imaging and image computing in computational physiology. IEEE TRANSACTIONS ON MEDICAL IMAGING 2013; 32:1-7. [PMID: 23409282 DOI: 10.1109/tmi.2012.2234320] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
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Burton BM, Tate JD, Erem B, Swenson DJ, Wang DF, Steffen M, Brooks DH, van Dam PM, Macleod RS. A toolkit for forward/inverse problems in electrocardiography within the SCIRun problem solving environment. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:267-70. [PMID: 22254301 DOI: 10.1109/iembs.2011.6090052] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Computational modeling in electrocardiography often requires the examination of cardiac forward and inverse problems in order to non-invasively analyze physiological events that are otherwise inaccessible or unethical to explore. The study of these models can be performed in the open-source SCIRun problem solving environment developed at the Center for Integrative Biomedical Computing (CIBC). A new toolkit within SCIRun provides researchers with essential frameworks for constructing and manipulating electrocardiographic forward and inverse models in a highly efficient and interactive way. The toolkit contains sample networks, tutorials and documentation which direct users through SCIRun-specific approaches in the assembly and execution of these specific problems.
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Affiliation(s)
- Brett M Burton
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA.
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33
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Abstract
Advances in computational geometric modeling, imaging, and simulation let researchers build and test models of increasing complexity, generating unprecedented amounts of data. As recent research in biomedical applications illustrates, visualization will be critical in making this vast amount of data usable; it's also fundamental to understanding models of complex phenomena.
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34
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Kolandaivelu A, Jayanti V, Halperin HR, Berger RD. Switchable Faraday shielding with application to reducing the pain of internal cardiac defibrillation while permitting external defibrillation. IEEE Trans Biomed Eng 2011; 59:409-16. [PMID: 22042127 DOI: 10.1109/tbme.2011.2173687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Switchable Faraday shielding is desirable in situations where electric field shielding is required at certain times and undesirable at other times. In this study, electrostatic finite element modeling was used to assess the effect of different shield geometries on the leakage of an internally applied field and penetration of an externally applied field. "Switching OFF" the shield by electrically disconnecting shield faces from each other was shown to significantly increase external field penetration. Applying this model to defibrillation, we looked at the effect of spacing and size of shield panels to maximize the ability to deliver an external defibrillation shock to the heart when shield panels are disconnected while providing acceptably low leakage of internal defibrillation shocks to avoid painful skeletal muscle capture when shield panels are connected. This analysis may be useful for designing internal defibrillator electrodes that preserve the efficacy of internal and external defibrillation while avoiding the significant morbidity associated with painful defibrillator shocks. Similar analysis could also guide optimizing the switchable Faraday shielding concept for other applications.
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Affiliation(s)
- Aravindan Kolandaivelu
- Cardiology Division, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA.
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The subcutaneous defibrillator will replace the transvenous defibrillator. J Interv Card Electrophysiol 2011; 32:73-7. [DOI: 10.1007/s10840-011-9570-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Accepted: 03/14/2011] [Indexed: 11/25/2022]
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Tate J, Stinstra J, Pilcher T, Poursaid A, Saarel E, MacLeod R. Measuring defibrillator surface potentials for simulation verification. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2011:239-242. [PMID: 22254294 PMCID: PMC6435960 DOI: 10.1109/iembs.2011.6090045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Though implantable cardioverter defibrillators (ICDs) are increasing in use in both adults and children, little progress has been devoted to optimizing device and electrode placement. To facilitate effective ICD placement, especially in pediatric cases, we have developed a predictive model that evaluates the efficacy of a delivered shock. We have also developed an experimental validation approach based on measurements from clinical cases. The approach involves obtaining body surface potential maps of ICD discharges during implantation surgery using a limited lead selection and body surface estimation algorithm. Comparison of the simulated and measured potentials yielded very similar patterns and a typical correlation greater than 0.93, suggesting that the predictive simulation generates realistic potential values. This validation approach provides confidence in application of the simulation pipeline and offers areas to focus future improvements.
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Affiliation(s)
- Jess Tate
- Department of Bioengineering, University of Utah, Salt Lake City, UT 84112, USA. @sci.utah.edu
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Tate JD, Stinstra JG, Pilcher TA, Macleod RS. Measurement of Defibrillator Surface Potentials for Simulation Verification. COMPUTING IN CARDIOLOGY 2010; 37:853-856. [PMID: 21779128 PMCID: PMC3138150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Despite the growing use of implantable cardioverter defibrillators (ICDs) in adults and children, there has been little progress in optimizing device and electrode placement. To facilitate effective placement of ICDs, especially in pediatric cases, we have developed a predictive model that evaluates the efficacy of a delivered shock. Most recently, we have also developed an experimental validation approach based on measurements from clinical cases. The approach involves obtaining body surface potential maps of ICD discharges during implantation surgery and comparing these measured potentials with simulated surface potentials to determine simulation accuracy. Comparison of the simulated and measured potentials yielded very similar patterns and a typical correlation greater than 0.9, suggesting that the predictive simulation generates realistic potential values. Ongoing sensitivity studies will determine the robustness of the results and pave the way for use of this approach for assisting optimization of ICD use.
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Affiliation(s)
- Jess D Tate
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA
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38
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Bardy GH, Smith WM, Hood MA, Crozier IG, Melton IC, Jordaens L, Theuns D, Park RE, Wright DJ, Connelly DT, Fynn SP, Murgatroyd FD, Sperzel J, Neuzner J, Spitzer SG, Ardashev AV, Oduro A, Boersma L, Maass AH, Van Gelder IC, Wilde AA, van Dessel PF, Knops RE, Barr CS, Lupo P, Cappato R, Grace AA. An entirely subcutaneous implantable cardioverter-defibrillator. N Engl J Med 2010; 363:36-44. [PMID: 20463331 DOI: 10.1056/nejmoa0909545] [Citation(s) in RCA: 537] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Implantable cardioverter-defibrillators (ICDs) prevent sudden death from cardiac causes in selected patients but require the use of transvenous lead systems. To eliminate the need for venous access, we designed and tested an entirely subcutaneous ICD system. METHODS First, we conducted two short-term clinical trials to identify a suitable device configuration and assess energy requirements. We evaluated four subcutaneous ICD configurations in 78 patients who were candidates for ICD implantation and subsequently tested the best configuration in 49 additional patients to determine the subcutaneous defibrillation threshold in comparison with that of the standard transvenous ICD. Then we evaluated the long-term use of subcutaneous ICDs in a pilot study, involving 6 patients, which was followed by a trial involving 55 patients. RESULTS The best device configuration consisted of a parasternal electrode and a left lateral thoracic pulse generator. This configuration was as effective as a transvenous ICD for terminating induced ventricular fibrillation, albeit with a significantly higher mean (+/-SD) energy requirement (36.6+/-19.8 J vs. 11.1+/-8.5 J). Among patients who received a permanent subcutaneous ICD, ventricular fibrillation was successfully detected in 100% of 137 induced episodes. Induced ventricular fibrillation was converted twice in 58 of 59 patients (98%) with the delivery of 65-J shocks in two consecutive tests. Clinically significant adverse events included two pocket infections and four lead revisions. After a mean of 10+/-1 months, the device had successfully detected and treated all 12 episodes of spontaneous, sustained ventricular tachyarrhythmia. CONCLUSIONS In small, nonrandomized studies, an entirely subcutaneous ICD consistently detected and converted ventricular fibrillation induced during electrophysiological testing. The device also successfully detected and treated all 12 episodes of spontaneous, sustained ventricular tachyarrhythmia. (ClinicalTrials.gov numbers, NCT00399217 and NCT00853645.)
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Affiliation(s)
- Gust H Bardy
- Seattle Institute for Cardiac Research, Seattle, WA, USA.
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Berruezo A, Zeljko HM, Bartrons J, Mayol J, Prada F, Brugada J. Defibrillation threshold decrease with the supradiaphragmatic extracardiac implantable cardioverter-defibrillator implantation technique. Europace 2010; 12:1649-51. [PMID: 20543197 DOI: 10.1093/europace/euq181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Despite advances in implantable cardioverter-defibrillator (ICD) technology, the optimal ICD implantation technique for pediatric patients has not yet been established. One increasingly used option is totally extracardiac implantation. However, concern exists about the high defibrillation threshold (DFT) at the moment of implantation or during follow-up. We report the case of a 3-year-old boy with repetitive syncopal idiopathic ventricular tachycardia episodes treated with ICD implantation using the extracardiac technique. Changing device position from abdominal to a supradiaphragmatic, solved unsafe elevated discharge impedance and DFT during follow-up.
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Affiliation(s)
- Antonio Berruezo
- Arrhythmia Section, Cardiology Department, Thorax Institute, Hospital Clinic, Barcelona, Catalonia, Spain.
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40
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Finite element modeling of subcutaneous implantable defibrillator electrodes in an adult torso. Heart Rhythm 2010; 7:692-8. [PMID: 20230927 DOI: 10.1016/j.hrthm.2010.01.030] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 01/10/2010] [Indexed: 11/23/2022]
Abstract
BACKGROUND Total subcutaneous implantable subcutaneous defibrillators are in development, but optimal electrode configurations are not known. OBJECTIVE We used image-based finite element models (FEM) to predict the myocardial electric field generated during defibrillation shocks (pseudo-DFT) in a wide variety of reported and innovative subcutaneous electrode positions to determine factors affecting optimal lead positions for subcutaneous implantable cardioverter-defibrillators (S-ICD). METHODS An image-based FEM of an adult man was used to predict pseudo-DFTs across a wide range of technically feasible S-ICD electrode placements. Generator location, lead location, length, geometry and orientation, and spatial relation of electrodes to ventricular mass were systematically varied. Best electrode configurations were determined, and spatial factors contributing to low pseudo-DFTs were identified using regression and general linear models. RESULTS A total of 122 single-electrode/array configurations and 28 dual-electrode configurations were simulated. Pseudo-DFTs for single-electrode orientations ranged from 0.60 to 16.0 (mean 2.65 +/- 2.48) times that predicted for the base case, an anterior-posterior configuration recently tested clinically. A total of 32 of 150 tested configurations (21%) had pseudo-DFT ratios </=1, indicating the possibility of multiple novel, efficient, and clinically relevant orientations. Favorable alignment of lead-generator vector with ventricular myocardium and increased lead length were the most important factors correlated with pseudo-DFT, accounting for 70% of the predicted variation (R(2) = 0.70, each factor P < .05) in a combined general linear model in which parameter estimates were calculated for each factor. CONCLUSION Further exploration of novel and efficient electrode configurations may be of value in the development of the S-ICD technologies and implant procedure. FEM modeling suggests that the choice of configurations that maximize shock vector alignment with the center of myocardial mass and use of longer leads is more likely to result in lower DFT.
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42
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Radbill AE, Triedman JK, Berul CI, Fynn-Thompson F, Atallah J, Alexander ME, Walsh EP, Cecchin F. System survival of nontransvenous implantable cardioverter-defibrillators compared to transvenous implantable cardioverter-defibrillators in pediatric and congenital heart disease patients. Heart Rhythm 2010; 7:193-8. [PMID: 20022820 DOI: 10.1016/j.hrthm.2009.10.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2009] [Accepted: 10/11/2009] [Indexed: 10/20/2022]
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Neal ML, Kerckhoffs R. Current progress in patient-specific modeling. Brief Bioinform 2010; 11:111-26. [PMID: 19955236 PMCID: PMC2810113 DOI: 10.1093/bib/bbp049] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 09/20/2009] [Indexed: 11/13/2022] Open
Abstract
We present a survey of recent advancements in the emerging field of patient-specific modeling (PSM). Researchers in this field are currently simulating a wide variety of tissue and organ dynamics to address challenges in various clinical domains. The majority of this research employs three-dimensional, image-based modeling techniques. Recent PSM publications mostly represent feasibility or preliminary validation studies on modeling technologies, and these systems will require further clinical validation and usability testing before they can become a standard of care. We anticipate that with further testing and research, PSM-derived technologies will eventually become valuable, versatile clinical tools.
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Affiliation(s)
- Maxwell Lewis Neal
- Division of Biomedical and Health Informatics, University of Washington, USA
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44
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Affiliation(s)
- Natalia Trayanova
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, MD 21224 USA
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45
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Boyle PM, Deo M, Plank G, Vigmond EJ. Purkinje-mediated effects in the response of quiescent ventricles to defibrillation shocks. Ann Biomed Eng 2009; 38:456-68. [PMID: 19876737 DOI: 10.1007/s10439-009-9829-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Accepted: 10/20/2009] [Indexed: 10/20/2022]
Abstract
In normal cardiac function, orderly activation of the heart is facilitated by the Purkinje system (PS), a specialized network of fast-conducting fibers that lines the ventricles. Its role during ventricular defibrillation remains unelucidated. Physical characteristics of the PS make it a poor candidate for direct electrical observation using contemporary experimental techniques. This study uses a computer modeling approach to assess contributions by the PS to the response to electrical stimulation. Normal sinus rhythm was simulated and epicardial breakthrough sites were distributed in a manner consistent with experimental results. Defibrillation shocks of several strengths and orientations were applied to quiescent ventricles, with and without PS, and electrical activation was analyzed. All shocks induced local polarizations in PS branches parallel to the field, which led to the rapid spread of excitation through the network. This produced early activations at myocardial sites where tissue was unexcited by the shock and coupled to the PS. Shocks along the apico-basal axis of the heart resulted in a significant abbreviation of activation time when the PS was present; these shocks are of particular interest because the fields generated by internal cardioverter defibrillators tend to have a strong component in the same direction. The extent of PS-induced changes, both temporal and spatial, was constrained by the amount of shock-activated myocardium. Increasing field strength decreased the transmission delay between PS and ventricular tissue at Purkinje-myocardial junctions (PMJs), but this did not have a major effect on the organ-level response. Weaker shocks directly affect a smaller volume of myocardial tissue but easily excite the PS, which makes the PS contribution to far field excitation more substantial than for stronger shocks.
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Affiliation(s)
- Patrick M Boyle
- Department of Electrical & Computer Engineering, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N1N4, Canada.
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MacLeod RS, Stinstra JG, Lew S, Whitaker RT, Swenson DJ, Cole MJ, Krüger J, Brooks DH, Johnson CR. Subject-specific, multiscale simulation of electrophysiology: a software pipeline for image-based models and application examples. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2009; 367:2293-2310. [PMID: 19414456 PMCID: PMC2696107 DOI: 10.1098/rsta.2008.0314] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Many simulation studies in biomedicine are based on a similar sequence of processing steps, starting from images and running through geometric model generation, assignment of tissue properties, numerical simulation and visualization of the results--a process known as image-based geometric modelling and simulation. We present an overview of software systems for implementing such a sequence both within highly integrated problem-solving environments and in the form of loosely integrated pipelines. Loose integration in this case indicates that individual programs function largely independently but communicate through files of a common format and support simple scripting, so as to automate multiple executions wherever possible. We then describe three specific applications of such pipelines to translational biomedical research in electrophysiology.
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Affiliation(s)
- R S MacLeod
- Nora Eccles Harrison Cardiovascular Research and Training Institute (CVRTI), University of Utah, Salt Lake City, UT 84112, USA.
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Triedman JK, Jolley M, Stinstra J, Brooks DH, MacLeod R. Predictive modeling of defibrillation using hexahedral and tetrahedral finite element models: recent advances. J Electrocardiol 2008; 41:483-6. [PMID: 18817926 DOI: 10.1016/j.jelectrocard.2008.08.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Revised: 08/02/2008] [Accepted: 08/05/2008] [Indexed: 11/18/2022]
Abstract
Implanted cardioverter/defribillator (ICD) implants may be complicated by body size and anatomy. One approach to this problem has been the adoption of creative, extracardiac implant strategies using standard ICD components. Because data on safety or efficacy of such ad hoc implant strategies are lacking, we have developed image-based finite element models to compare electric fields and expected defibrillation thresholds (DFTs) using standard and novel electrode locations. In this article, we review recently published studies by our group using such models and progress in meshing strategies to improve efficiency and visualization. Our preliminary observations predict that they may be large changes in defibrillation thresholds with clinically relevant variations of electrode placement. Extracardiac ICDs of various lead configurations are predicted to be effective in both children and adults. This approach may aid both ICD development and patient-specific optimization of electrode placement, but the simplified nature of current models dictates further development and validation before clinical or industrial use.
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Affiliation(s)
- John K Triedman
- Department of Cardiology, Children's Hospital Boston, Boston, MA, USA.
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Finite element modeling of novel ICD configurations in pediatric and congenital heart disease: Validation of the MacGyver principle? Heart Rhythm 2008; 5:573-4. [DOI: 10.1016/j.hrthm.2008.02.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Indexed: 11/19/2022]
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50
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Trayanova N. In the Spotlight: Cardiovascular Engineering. IEEE Rev Biomed Eng 2008; 1:12-4. [DOI: 10.1109/rbme.2008.2008230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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