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McBride S, Avazzadeh S, Wheatley AM, O’Brien B, Coffey K, Elahi A, O’Halloran M, Quinlan LR. Ablation Modalities for Therapeutic Intervention in Arrhythmia-Related Cardiovascular Disease: Focus on Electroporation. J Clin Med 2021; 10:jcm10122657. [PMID: 34208708 PMCID: PMC8235263 DOI: 10.3390/jcm10122657] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 06/13/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
Targeted cellular ablation is being increasingly used in the treatment of arrhythmias and structural heart disease. Catheter-based ablation for atrial fibrillation (AF) is considered a safe and effective approach for patients who are medication refractory. Electroporation (EPo) employs electrical energy to disrupt cell membranes which has a minimally thermal effect. The nanopores that arise from EPo can be temporary or permanent. Reversible electroporation is transitory in nature and cell viability is maintained, whereas irreversible electroporation causes permanent pore formation, leading to loss of cellular homeostasis and cell death. Several studies report that EPo displays a degree of specificity in terms of the lethal threshold required to induce cell death in different tissues. However, significantly more research is required to scope the profile of EPo thresholds for specific cell types within complex tissues. Irreversible electroporation (IRE) as an ablative approach appears to overcome the significant negative effects associated with thermal based techniques, particularly collateral damage to surrounding structures. With further fine-tuning of parameters and longer and larger clinical trials, EPo may lead the way of adapting a safer and efficient ablation modality for the treatment of persistent AF.
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Affiliation(s)
- Shauna McBride
- Physiology and Cellular Physiology Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, National University of Ireland (NUI) Galway, H91 W5P7 Galway, Ireland; (S.M.); (S.A.); (A.M.W.)
| | - Sahar Avazzadeh
- Physiology and Cellular Physiology Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, National University of Ireland (NUI) Galway, H91 W5P7 Galway, Ireland; (S.M.); (S.A.); (A.M.W.)
| | - Antony M. Wheatley
- Physiology and Cellular Physiology Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, National University of Ireland (NUI) Galway, H91 W5P7 Galway, Ireland; (S.M.); (S.A.); (A.M.W.)
| | - Barry O’Brien
- AtriAN Medical Limited, Unit 204, NUIG Business Innovation Centre, Upper Newcastle, H91 R6W6 Galway, Ireland; (B.O.); (K.C.)
| | - Ken Coffey
- AtriAN Medical Limited, Unit 204, NUIG Business Innovation Centre, Upper Newcastle, H91 R6W6 Galway, Ireland; (B.O.); (K.C.)
| | - Adnan Elahi
- Translational Medical Device Lab (TMDL), Lamb Translational Research Facility, University College Hospital Galway, H91 V4AY Galway, Ireland; (A.E.); (M.O.)
- Electrical & Electronic Engineering, School of Engineering, National University of Ireland Galway, H91 HX31 Galway, Ireland
| | - Martin O’Halloran
- Translational Medical Device Lab (TMDL), Lamb Translational Research Facility, University College Hospital Galway, H91 V4AY Galway, Ireland; (A.E.); (M.O.)
| | - Leo R. Quinlan
- Physiology and Cellular Physiology Laboratory, CÚRAM SFI Centre for Research in Medical Devices, School of Medicine, Human Biology Building, National University of Ireland (NUI) Galway, H91 W5P7 Galway, Ireland; (S.M.); (S.A.); (A.M.W.)
- CÚRAM, SFI Research Centre for Medical Devices, National University of Ireland Galway, H92 W2TY Galway, Ireland
- Correspondence:
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Clementy N, Bodin A, Bisson A, Teixeira-Gomes AP, Roger S, Angoulvant D, Labas V, Babuty D. The Defibrillation Conundrum: New Insights into the Mechanisms of Shock-Related Myocardial Injury Sustained from a Life-Saving Therapy. Int J Mol Sci 2021; 22:5003. [PMID: 34066832 PMCID: PMC8125879 DOI: 10.3390/ijms22095003] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/03/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022] Open
Abstract
Implantable cardiac defibrillators (ICDs) are recommended to prevent the risk of sudden cardiac death. However, shocks are associated with an increased mortality with a dose response effect, and a strategy of reducing electrical therapy burden improves the prognosis of implanted patients. We review the mechanisms of defibrillation and its consequences, including cell damage, metabolic remodeling, calcium metabolism anomalies, and inflammatory and pro-fibrotic remodeling. Electrical shocks do save lives, but also promote myocardial stunning, heart failure, and pro-arrhythmic effects as seen in electrical storms. Limiting unnecessary implantations and therapies and proposing new methods of defibrillation in the future are recommended.
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Affiliation(s)
- Nicolas Clementy
- Service de Cardiologie, Hôpital Trousseau, Université de Tours, 37044 Tours, France; (A.B.); (A.B.); (D.A.); (D.B.)
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France;
| | - Alexandre Bodin
- Service de Cardiologie, Hôpital Trousseau, Université de Tours, 37044 Tours, France; (A.B.); (A.B.); (D.A.); (D.B.)
| | - Arnaud Bisson
- Service de Cardiologie, Hôpital Trousseau, Université de Tours, 37044 Tours, France; (A.B.); (A.B.); (D.A.); (D.B.)
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France;
| | - Ana-Paula Teixeira-Gomes
- Plate-forme de Chirurgie et d’Imagerie pour la Recherche et l’Enseignement (CIRE), INRA, Université de Tours, CHU de Tours, 37380 Nouzilly, France; (A.-P.T.-G.); (V.L.)
| | - Sebastien Roger
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France;
| | - Denis Angoulvant
- Service de Cardiologie, Hôpital Trousseau, Université de Tours, 37044 Tours, France; (A.B.); (A.B.); (D.A.); (D.B.)
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France;
| | - Valérie Labas
- Plate-forme de Chirurgie et d’Imagerie pour la Recherche et l’Enseignement (CIRE), INRA, Université de Tours, CHU de Tours, 37380 Nouzilly, France; (A.-P.T.-G.); (V.L.)
| | - Dominique Babuty
- Service de Cardiologie, Hôpital Trousseau, Université de Tours, 37044 Tours, France; (A.B.); (A.B.); (D.A.); (D.B.)
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France;
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3
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Gagno G, Zoppo F. Insights on arrhythmia termination and type 2 breaks after ICD therapy delivery. Pacing Clin Electrophysiol 2020; 43:1039-1047. [DOI: 10.1111/pace.14030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/15/2020] [Accepted: 08/02/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Giulia Gagno
- Dipartimento di Cardiologia Università degli Studi di Trieste, Azienda Sanitaria Universitaria Giuliano, Isontina Trieste Italy
| | - Franco Zoppo
- Elettrofisiologia, Unità Operativa di Cardiologia, Ospedale Civile di Gorizia Azienda Sanitaria Universitaria Giuliano, Isontina Trieste Italy
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Varghese F, Neuber JU, Xie F, Philpott JM, Pakhomov AG, Zemlin CW. Low-energy defibrillation with nanosecond electric shocks. Cardiovasc Res 2018; 113:1789-1797. [PMID: 29016714 DOI: 10.1093/cvr/cvx172] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 08/28/2017] [Indexed: 02/01/2023] Open
Abstract
Aims Reliable defibrillation with reduced energy deposition has long been the focus of defibrillation research. We studied the efficacy of single shocks of 300 ns duration in defibrillating rabbit hearts as well as the tissue damage they may cause. Methods and results New Zealand white rabbit hearts were Langendorff-perfused and two planar electrodes were placed on either side of the heart. Shocks of 300 ns duration and 0.3-3 kV amplitude were generated with a transmission line generator. Single nanosecond shocks consistently induced waves of electrical activation, with a stimulation threshold of 0.9 kV (over 3 cm) and consistent activation for shock amplitudes of 1.2 kV or higher (9/9 successful attempts). We induced fibrillation (35 episodes in 12 hearts) and found that single shock nanosecond-defibrillation could consistently be achieved, with a defibrillation threshold of 2.3-2.4 kV (over 3 cm), and consistent success at 3 kV (11/11 successful attempts). Shocks uniformly depolarized the tissue, and the threshold energy needed for nanosecond defibrillation was almost an order of magnitude lower than the energy needed for defibrillation with a monophasic 10 ms shock delivered with the same electrode configuration. For the parameters studied here, nanosecond defibrillation caused no baseline shift of the transmembrane potential (that could be indicative of electroporative damage), no changes in action potential duration, and only a brief change of diastolic interval, for one beat after the shock was delivered. Histological staining with tetrazolium chloride and propidium iodide showed that effective defibrillation was not associated with tissue death or with detectable electroporation anywhere in the heart (six hearts). Conclusion Nanosecond-defibrillation is a promising technology that may allow clinical defibrillation with profoundly reduced energies.
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Affiliation(s)
- Frency Varghese
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA.,Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Norfolk, VA 23508, USA
| | - Johanna U Neuber
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA.,Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Norfolk, VA 23508, USA
| | - Fei Xie
- Department of Engineering, Mount Vernon Nazarene University, Mount Vernon, OH, USA
| | | | - Andrei G Pakhomov
- Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Norfolk, VA 23508, USA
| | - Christian W Zemlin
- Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, USA.,Center for Bioelectrics, Old Dominion University, 4211 Monarch Way, Norfolk, VA 23508, USA
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Kostrzewa M, Tueluemen E, Rudic B, Rathmann N, Akin I, Henzler T, Liebe V, Schoenberg SO, Borggrefe M, Diehl SJ. Cardiac impact of R-wave triggered irreversible electroporation therapy. Heart Rhythm 2018; 15:1872-1879. [PMID: 30017817 DOI: 10.1016/j.hrthm.2018.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND Irreversible electroporation (IRE) is a novel tumor ablative therapy technique, using electric fields to induce apoptosis in target tissues. Whether these electric pulses of high field strength can cause cardiac damage and/or ablation-induced arrhythmias is unclear. OBJECTIVE The purpose of this study was to systematically evaluate the safety of electrocardiogram (ECG)-gated IRE with regard to cardiac side effects. METHODS In all patients, 12-lead ECG and signal-averaged ECG (SAECG) recordings were performed before and after IRE and 24-hour Holter recording on the day of the IRE procedure. Venous blood samples (N-terminal pro-brain-type natriuretic peptide [NT-proBNP], high-sensitive troponin I [hsTnI]) were obtained before and 4 and 16 hours after the procedure. Patients with abnormal findings were reevaluated after 3 months. RESULTS In total, 26 patients with an oncologic indication for IRE (11 females, mean age 62.9 years) were prospectively enrolled. Nine patients (34.6%) showed an increase in hsTnI and 21 patients (80.8%) an increase in NT-proBNP after ablation. Fifteen patients (57%) developed arrhythmias related to the procedure. One patient, in whom hsTnI and NT-proBNP had increased, developed multiple, nonsustained ventricular tachycardia events. In another patient, atrial fibrillation was triggered twice in 2 separate procedures. Twelve patients had clinically benign arrhythmias. SAECG was negative in all patients. CONCLUSION Subclinical myocardial injury and nonfatal cardiac arrhythmias can occur in the context of IRE treatment. Although no sustained cardiac injuries could be found at 3-month follow-up, we propose implementation of a cardiac safety algorithm consisting of cardiac biomarkers and ECG monitoring when IRE is conducted.
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Affiliation(s)
- Michael Kostrzewa
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Erol Tueluemen
- DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Boris Rudic
- DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Nils Rathmann
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Ibrahim Akin
- DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Thomas Henzler
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Volker Liebe
- DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Stefan O Schoenberg
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Martin Borggrefe
- DZHK (German Centre for Cardiovascular Research) Partner Site Heidelberg/Mannheim, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Steffen J Diehl
- Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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6
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Semenov I, Grigoryev S, Neuber JU, Zemlin CW, Pakhomova ON, Casciola M, Pakhomov AG. Excitation and injury of adult ventricular cardiomyocytes by nano- to millisecond electric shocks. Sci Rep 2018; 8:8233. [PMID: 29844431 PMCID: PMC5974370 DOI: 10.1038/s41598-018-26521-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 05/08/2018] [Indexed: 12/13/2022] Open
Abstract
Intense electric shocks of nanosecond (ns) duration can become a new modality for more efficient but safer defibrillation. We extended strength-duration curves for excitation of cardiomyocytes down to 200 ns, and compared electroporative damage by proportionally more intense shocks of different duration. Enzymatically isolated murine, rabbit, and swine adult ventricular cardiomyocytes (VCM) were loaded with a Ca2+ indicator Fluo-4 or Fluo-5N and subjected to shocks of increasing amplitude until a Ca2+ transient was optically detected. Then, the voltage was increased 5-fold, and the electric cell injury was quantified by the uptake of a membrane permeability marker dye, propidium iodide. We established that: (1) Stimuli down to 200-ns duration can elicit Ca2+ transients, although repeated ns shocks often evoke abnormal responses, (2) Stimulation thresholds expectedly increase as the shock duration decreases, similarly for VCMs from different species, (3) Stimulation threshold energy is minimal for the shortest shocks, (4) VCM orientation with respect to the electric field does not affect the threshold for ns shocks, and (5) The shortest shocks cause the least electroporation injury. These findings support further exploration of ns defibrillation, although abnormal response patterns to repetitive ns stimuli are of a concern and require mechanistic analysis.
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Affiliation(s)
- Iurii Semenov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Sergey Grigoryev
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Johanna U Neuber
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Christian W Zemlin
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.,Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA, 23508, USA
| | - Olga N Pakhomova
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Maura Casciola
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA
| | - Andrei G Pakhomov
- Frank Reidy Research Center for Bioelectrics, Old Dominion University, Norfolk, VA, 23508, USA.
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7
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Jenkins MW, Wang YT, Doughman YQ, Watanabe M, Cheng Y, Rollins AM. Optical pacing of the adult rabbit heart. BIOMEDICAL OPTICS EXPRESS 2013; 4:1626-35. [PMID: 24049683 PMCID: PMC3771833 DOI: 10.1364/boe.4.001626] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 07/21/2013] [Accepted: 07/30/2013] [Indexed: 05/03/2023]
Abstract
Optical pacing has been demonstrated to be a viable alternative to electrical pacing in embryonic hearts. In this study, the feasibility of optically pacing an adult rabbit heart was explored. Hearts from adult New Zealand White rabbits (n = 9) were excised, cannulated and perfused on a modified Langendorff apparatus. Pulsed laser light (λ = 1851 nm) was directed to either the left or right atrium through a multimode optical fiber. An ECG signal from the left ventricle and a trigger pulse from the laser were recorded simultaneously to determine when capture was achieved. Successful optical pacing was demonstrated by obtaining pacing capture, stopping, then recapturing as well as by varying the pacing frequency. Stimulation thresholds measured at various pulse durations suggested that longer pulses (8 ms) had a lower energy capture threshold. To determine whether optical pacing caused damage, two hearts were perfused with 30 µM of propidium iodide and analyzed histologically. A small number of cells near the stimulation site had compromised cell membranes, which probably limited the time duration over which pacing was maintained. Here, short-term optical pacing (few minutes duration) is demonstrated in the adult rabbit heart for the first time. Future studies will be directed to optimize optical pacing parameters to decrease stimulation thresholds and may enable longer-term pacing.
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Affiliation(s)
- Michael W. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, 11000 Euclid Ave., Cleveland, Oh. 44106 USA
| | - Y. T. Wang
- Department of Biomedical Engineering, Case Western Reserve University, 11000 Euclid Ave., Cleveland, Oh. 44106 USA
- Department of Molecular Cardiology, Cleveland Clinic, 9500 Euclid Ave., Cleveland, Oh. 44195 USA
| | - Y. Q. Doughman
- Department of Pediatrics, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Oh. 44106 USA
| | - M. Watanabe
- Department of Pediatrics, Case Western Reserve University, 10900 Euclid Ave., Cleveland, Oh. 44106 USA
| | - Y. Cheng
- Department of Biomedical Engineering, Case Western Reserve University, 11000 Euclid Ave., Cleveland, Oh. 44106 USA
- Department of Molecular Cardiology, Cleveland Clinic, 9500 Euclid Ave., Cleveland, Oh. 44195 USA
- Department of Cardiovascular Medicine, Cleveland Clinic, 9500 Euclid Ave., Cleveland, Oh. 44195 USA
| | - A. M. Rollins
- Department of Biomedical Engineering, Case Western Reserve University, 11000 Euclid Ave., Cleveland, Oh. 44106 USA
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Huang J, Walcott GP, Ruse RB, Bohanan SJ, Killingsworth CR, Ideker RE. Ascending-ramp biphasic waveform has a lower defibrillation threshold and releases less troponin I than a truncated exponential biphasic waveform. Circulation 2012; 126:1328-33. [PMID: 22865891 DOI: 10.1161/circulationaha.112.109777] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND We tested the hypothesis that the shape of the shock waveform affects not only the defibrillation threshold but also the amount of cardiac damage. METHODS AND RESULTS Defibrillation thresholds were determined for 11 waveforms-3 ascending-ramp waveforms, 3 descending-ramp waveforms, 3 rectilinear first-phase biphasic waveforms, a Gurvich waveform, and a truncated exponential biphasic waveform-in 6 pigs with electrodes in the right ventricular apex and superior vena cava. The ascending, descending, and rectilinear waveforms had 4-, 8-, and 16-millisecond first phases and a 3.5-millisecond rectilinear second phase that was half the voltage of the first phase. The exponential biphasic waveform had a 60% first-phase and a 50% second-phase tilt. In a second study, we attempted to defibrillate after 10 seconds of ventricular fibrillation with a single ≈30-J shock (6 pigs successfully defibrillated with 8-millisecond ascending, 8-millisecond rectilinear, and truncated exponential biphasic waveforms). Troponin I blood levels were determined before and 2 to 10 hours after the shock. The lowest-energy defibrillation threshold was for the 8-milliseconds ascending ramp (14.6±7.3 J [mean±SD]), which was significantly less than for the truncated exponential (19.6±6.3 J). Six hours after shock, troponin I was significantly less for the ascending-ramp waveform (0.80±0.54 ng/mL) than for the truncated exponential (1.92±0.47 ng/mL) or the rectilinear waveform (1.17±0.45 ng/mL). CONCLUSIONS The ascending ramp has a significantly lower defibrillation threshold and at ≈30 J causes 58% less troponin I release than the truncated exponential biphasic shock. Therefore, the shock waveform affects both the defibrillation threshold and the amount of cardiac damage.
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Affiliation(s)
- Jian Huang
- University of Alabama-Birmingham, 1670 University Blvd, Room B140 Volker Hall, Birmingham, AL 35294-0019, USA.
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9
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Wang YT, Efimov IR, Cheng Y. Electroporation induced by internal defibrillation shock with and without recovery in intact rabbit hearts. Am J Physiol Heart Circ Physiol 2012; 303:H439-49. [PMID: 22730387 DOI: 10.1152/ajpheart.01121.2011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Defibrillation shocks from implantable cardioverter defibrillators can be lifesaving but can also damage cardiac tissues via electroporation. This study characterizes the spatial distribution and extent of defibrillation shock-induced electroporation with and without a 45-min postshock period for cell membranes to recover. Langendorff-perfused rabbit hearts (n = 31) with and without a chronic left ventricular (LV) myocardial infarction (MI) were studied. Mean defibrillation threshold (DFT) was determined to be 161.4 ± 17.1 V and 1.65 ± 0.44 J in MI hearts for internally delivered 8-ms monophasic truncated exponential (MTE) shocks during sustained ventricular fibrillation (>20 s, SVF). A single 300-V MTE shock (twice determined DFT voltage) was used to terminate SVF. Shock-induced electroporation was assessed by propidium iodide (PI) uptake. Ventricular PI staining was quantified by fluorescent imaging. Histological analysis was performed using Masson's Trichrome staining. Results showed PI staining concentrated near the shock electrode in all hearts. Without recovery, PI staining was similar between normal and MI groups around the shock electrode and over the whole ventricles. However, MI hearts had greater total PI uptake in anterior (P < 0.01) and posterior (P < 0.01) LV epicardial regions. Postrecovery, PI staining was reduced substantially, but residual staining remained significant with similar spacial distributions. PI staining under SVF was similar to previously studied paced hearts. In conclusion, electroporation was spatially correlated with the active region of the shock electrode. Additional electroporation occurred in the LV epicardium of MI hearts, in the infarct border zone. Recovery of membrane integrity postelectroporation is likely a prolonged process. Short periods of SVF did not affect electroporation injury.
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Affiliation(s)
- Yves T Wang
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, Ohio, USA
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10
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Rantner LJ, Arevalo HJ, Constantino JL, Efimov IR, Plank G, Trayanova NA. Three-dimensional mechanisms of increased vulnerability to electric shocks in myocardial infarction: altered virtual electrode polarizations and conduction delay in the peri-infarct zone. J Physiol 2012; 590:4537-51. [PMID: 22586222 DOI: 10.1113/jphysiol.2012.229088] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Defibrillation efficacy is decreased in infarcted hearts, but the mechanisms by which infarcted hearts are more vulnerable to electric shocks than healthy hearts remain poorly understood. The goal of this study was to provide insight into the 3D mechanisms for the increased vulnerability to electric shocks in infarcted hearts. We hypothesized that changes in virtual electrode polarizations (VEPs) and propagation delay through the peri-infarct zone (PZ) were responsible. We developed a micro anatomically detailed rabbit ventricular model with chronic myocardial infarction from magnetic resonance imaging and enriched the model with data from optical mapping experiments. We further developed a control model without the infarct. The simulation protocol involved apical pacing followed by biphasic shocks. Simulation results from both models were compared.The upper limit of vulnerability(ULV) was 8 V cm(-1) in the infarction model and 4 V cm(-1) in the control model. VEPs were less pronounced in the infarction model, providing a larger excitable area for postshock propagation but smaller transmembrane potential gradients to initiate new wavefronts. Initial post-shock transmural activation occurred at a later time in the infarction model, and the PZ served to delay propagation in subsequent beats. The presence of the PZ was found to be responsible for the increased vulnerability.
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Affiliation(s)
- Lukas J Rantner
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21218, USA
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11
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Wang YT, Popović ZB, Efimov IR, Cheng Y. Longitudinal study of cardiac remodelling in rabbits following infarction. Can J Cardiol 2012; 28:230-8. [PMID: 22265993 PMCID: PMC4754104 DOI: 10.1016/j.cjca.2011.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 11/03/2011] [Accepted: 11/03/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Cardiac remodelling following myocardial infarction (MI) is a complex, dynamic process. There have been few longitudinal studies of these changes. METHODS A 2-dimensional transthoracic echocardiography was performed on 20 rabbits, before and 1, 2, 4, 8, and 12 weeks after MI (n = 14) and twice for controls (n = 6). Chronic left ventricular (LV) infarct size was histologically characterized and correlated with mechanical function. A linear mixed model was used to analyze longitudinal and infarct size-related changes in LV end-systolic volume (ESV), end-diastolic volume (EDV), ejection fraction (EF), sphericity, circumferential strain, and wall motion score index. RESULTS Mean LV infarct size was 28.9% ± 9.3%. After MI, rapid remodelling occurred in LVESV, LVEF, and sphericity for 2 weeks and LVEDV for 4 weeks, with slower changes afterwards. LV infarct size correlated with LVESV (r = 0.76), LVEDV (r = 0.71), and LVEF (r = 0.69). Larger infarcts resulted in greater LVESV dilation (P = 0.04) and faster LVEDV (P < 0.01), LVEF (P < 0.01), and sphericity (P < 0.01) remodelling. Apical global circumferential strain and wall motion score index increased for 1 week, then stabilized, regardless of infarct size, and apical global circumferential strain was correlated with apical infarction (r = 0.58). Additionally, regional circumferential strain decreased in segments with severe (> 80%) infarction more quickly (P < 0.01) and by a greater degree (P = 0.04) compared with segments with minor (< 20%) infarction. CONCLUSIONS The most dynamic remodelling of cardiac function in this model occurred during the first 4 weeks, stabilizing thereafter, with changes maintained up to 12 weeks. Infarct size affected both the early rate and long-term extent of mechanical remodelling.
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Affiliation(s)
- Yves T. Wang
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH
| | - Zoran B. Popović
- Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH
| | - Igor R. Efimov
- Department of Biomedical Engineering, Washington University, St. Louis, MO
| | - Yuanna Cheng
- Department of Molecular Cardiology, Cleveland Clinic, Cleveland, OH
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH
- Department of Cardiovascular Medicine, Cleveland Clinic, Cleveland, OH
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Vadakkumpadan F, Arevalo H, Prassl AJ, Chen J, Kickinger F, Kohl P, Plank G, Trayanova N. Image-based models of cardiac structure in health and disease. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2010; 2:489-506. [PMID: 20582162 DOI: 10.1002/wsbm.76] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Computational approaches to investigating the electromechanics of healthy and diseased hearts are becoming essential for the comprehensive understanding of cardiac function. In this article, we first present a brief review of existing image-based computational models of cardiac structure. We then provide a detailed explanation of a processing pipeline which we have recently developed for constructing realistic computational models of the heart from high resolution structural and diffusion tensor (DT) magnetic resonance (MR) images acquired ex vivo. The presentation of the pipeline incorporates a review of the methodologies that can be used to reconstruct models of cardiac structure. In this pipeline, the structural image is segmented to reconstruct the ventricles, normal myocardium, and infarct. A finite element mesh is generated from the segmented structural image, and fiber orientations are assigned to the elements based on DTMR data. The methods were applied to construct seven different models of healthy and diseased hearts. These models contain millions of elements, with spatial resolutions in the order of hundreds of microns, providing unprecedented detail in the representation of cardiac structure for simulation studies.
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Affiliation(s)
- Fijoy Vadakkumpadan
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Hermenegild Arevalo
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Anton J Prassl
- Institute of Biophysics and Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Junjie Chen
- Consortium for Translational Research in Advanced Imaging and Nanomedicine, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Peter Kohl
- Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford, UK
| | - Gernot Plank
- Institute of Biophysics and Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Natalia Trayanova
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
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Vadakkumpadan F, Rantner LJ, Tice B, Boyle P, Prassl AJ, Vigmond E, Plank G, Trayanova N. Image-based models of cardiac structure with applications in arrhythmia and defibrillation studies. J Electrocardiol 2009; 42:157.e1-10. [PMID: 19181330 PMCID: PMC2819337 DOI: 10.1016/j.jelectrocard.2008.12.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2008] [Indexed: 11/22/2022]
Abstract
The objective of this article is to present a set of methods for constructing realistic computational models of cardiac structure from high-resolution structural and diffusion tensor magnetic resonance images and to demonstrate the applicability of the models in simulation studies. The structural image is segmented to identify various regions such as normal myocardium, ventricles, and infarct. A finite element mesh is generated from the processed structural data, and fiber orientations are assigned to the elements. The Purkinje system, when visible, is modeled using linear elements that interconnect a set of manually identified points. The methods were applied to construct 2 different models; and 2 simulation studies, which demonstrate the applicability of the models in the analysis of arrhythmia and defibrillation, were performed. The models represent cardiac structure with unprecedented detail for simulation studies.
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Affiliation(s)
- Fijoy Vadakkumpadan
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, MD, USA
| | - Lukas J. Rantner
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, MD, USA
| | - Brock Tice
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, MD, USA
| | - Patrick Boyle
- Department of Electrical and Computer Engineering, University of Calgary, AB, Canada
| | - Anton J. Prassl
- Institute of Biophysics, Medical University of Graz, Graz, Austria
| | - Edward Vigmond
- Department of Electrical and Computer Engineering, University of Calgary, AB, Canada
| | - Gernot Plank
- Institute of Biophysics and Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Natalia Trayanova
- Institute for Computational Medicine and the Department of Biomedical Engineering, Johns Hopkins University, MD, USA
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