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Mathuria N, Royal ALR, Enterría-Rosales J, Carcamo-Bahena Y, Terracciano R, Dave A, Valderrabano M, Filgueira CS. Near-infrared sensitive nanoparticle-mediated photothermal ablation of ventricular myocardium. Heart Rhythm 2022; 19:1550-1556. [PMID: 35562055 DOI: 10.1016/j.hrthm.2022.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/20/2022] [Accepted: 05/02/2022] [Indexed: 01/25/2023]
Affiliation(s)
- Nilesh Mathuria
- Houston Methodist Heart and Vascular Center, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas
| | - Amber Lee R Royal
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas
| | - Julia Enterría-Rosales
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas; School of Medicine, Instituto Tecnológico de Monterrey, Monterrey, Mexico
| | | | - Rossana Terracciano
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas; Department of Electronics, Politecnico di Torino, Torino, Italy
| | - Amish Dave
- Houston Methodist Heart and Vascular Center, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas
| | - Miguel Valderrabano
- Houston Methodist Heart and Vascular Center, Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas
| | - Carly S Filgueira
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, Texas; Department of Cardiovascular Surgery, Houston Methodist Research Institute, Houston, Texas.
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On the quest of the optimal blanking period - Can we predict early arrhythmia recurrence after atrial fibrillation ablation using biomarkers? Int J Cardiol 2021; 340:34-35. [PMID: 34343530 DOI: 10.1016/j.ijcard.2021.07.051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 07/26/2021] [Indexed: 11/23/2022]
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Yano M, Egami Y, Ukita K, Kawamura A, Nakamura H, Matsuhiro Y, Yasumoto K, Tsuda M, Okamoto N, Matsunaga-Lee Y, Shutta R, Nishino M, Tanouchi J. Impact of myocardial injury and inflammation due to ablation on the short-term and mid-term outcomes: Cryoballoon versus laser balloon ablation. Int J Cardiol 2021; 338:102-108. [PMID: 34126131 DOI: 10.1016/j.ijcard.2021.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 06/01/2021] [Accepted: 06/09/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND Cryoballoon ablation (CBA) and laser balloon ablation (LBA) were developed as alternatives to conventional radiofrequency ablation for paroxysmal atrial fibrillation (PAF). Pathological findings after ablation such as myocardial injury and inflammation are thought to be different between CBA and LBA. However, the different impact of myocardial injury and inflammation after ablation on short- and mid-term outcomes remains unclear. METHODS Consecutive PAF patients who underwent CBA and LBA were enrolled from the Osaka Rosai Atrial Fibrillation ablation (ORAF) registry. The difference of the acute myocardial injury marker (hs-TnI), and changes of inflammation markers (C reactive protein; ΔCRP, and white blood cell; ΔWBC) after catheter ablation and the difference of the short-term (within 3 months after ablation) and mid-term (from 3 months to 6 months after ablation) outcomes were evaluated between the two groups. RESULTS The CBA and LBA groups consisted of 55 and 56 patients, respectively. After propensity score matching, CBA and LBA groups consisted of 37 patients, respectively. Hs-TnI value was significantly higher in CBA than LBA group, while ΔCRP and ΔWBC were significantly higher in LBA than CBA group. In the propensity score-matched pairs, the LBA group had a significantly greater risk of short-term arrhythmia recurrence than the CBA group, whereas no significant difference of mid-term arrhythmia recurrence were found between the two groups. CONCLUSION Myocardial injury and inflammation status differ between CBA and LBA groups. LBA group had stronger inflammation after ablation and had a significantly greater risk of short-term arrhythmia recurrence after PVI than CBA group.
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Affiliation(s)
- Masamichi Yano
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Yasuyuki Egami
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Kohei Ukita
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Akito Kawamura
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Hitoshi Nakamura
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Yutaka Matsuhiro
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Koji Yasumoto
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Masaki Tsuda
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Naotaka Okamoto
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Yasuharu Matsunaga-Lee
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Ryu Shutta
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
| | - Masami Nishino
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan.
| | - Jun Tanouchi
- Division of Cardiology, Osaka Rosai Hospital, 3-1179 Nagasonecho, kita-ku, Sakai, Osaka, 591-8025, Japan
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Skeete JR, Du-Fay-de-Lavallaz JM, Kenigsberg D, Macias C, Winterfield JR, Sharma PS, Trohman RG, Huang HD. Clinical Applications of Laser Technology: Laser Balloon Ablation in the Management of Atrial Fibrillation. MICROMACHINES 2021; 12:mi12020188. [PMID: 33673330 PMCID: PMC7917803 DOI: 10.3390/mi12020188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/03/2021] [Accepted: 02/08/2021] [Indexed: 11/24/2022]
Abstract
Catheter-based ablation techniques have a well-established role in atrial fibrillation (AF) management. The prevalence and impact of AF is increasing globally, thus mandating an emphasis on improving ablation techniques through innovation. One key area of ongoing evolution in this field is the use of laser energy to perform pulmonary vein isolation during AF catheter ablation. While laser use is not as widespread as other ablation techniques, such as radiofrequency ablation and cryoballoon ablation, advancements in product design and procedural protocols have demonstrated laser balloon ablation to be equally safe and effective compared to these other modalities. Additionally, strategies to improve procedural efficiency and decrease radiation exposure through low fluoroscopy protocols make this technology an increasingly promising and exciting option.
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Affiliation(s)
- Jamario R. Skeete
- Division of Cardiology, Rush University Medical Center, Chicago, IL 60612, USA; (J.R.S.); (P.S.S.); (R.G.T.)
| | | | - David Kenigsberg
- Division of Cardiology, Nova Southeastern University, Fort Lauderdale-Davie, FL 33314, USA;
| | - Carlos Macias
- Section of Cardiology, Ronald Reagan University of California Los Angeles Medical Center, Los Angeles, CA 90095, USA;
| | - Jeffrey R. Winterfield
- Division of Cardiology, Medical University of South Carolina, Charleston, SC 29425, USA;
| | - Parikshit S. Sharma
- Division of Cardiology, Rush University Medical Center, Chicago, IL 60612, USA; (J.R.S.); (P.S.S.); (R.G.T.)
| | - Richard G. Trohman
- Division of Cardiology, Rush University Medical Center, Chicago, IL 60612, USA; (J.R.S.); (P.S.S.); (R.G.T.)
| | - Henry D. Huang
- Division of Cardiology, Rush University Medical Center, Chicago, IL 60612, USA; (J.R.S.); (P.S.S.); (R.G.T.)
- Correspondence:
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Yasin OZ, Vaidya VR, Chacko SR, Asirvatham SJ. Inappropriate Sinus Tachycardia: Current Challenges and Future Directions. J Innov Card Rhythm Manag 2018; 9:3239-3243. [PMID: 32479576 PMCID: PMC7252682 DOI: 10.19102/icrm.2018.090706] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Affiliation(s)
- Omar Z. Yasin
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, MN, USA
| | | | | | - Samuel J. Asirvatham
- Division of Cardiovascular Disease, Mayo Clinic, Rochester, MN, USA
- Department of Pediatrics and Adolescent Medicine, Mayo Clinic, Rochester, MN, USA
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6
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Yagishita D, Ajijola OA, Vaseghi M, Nsair A, Zhou W, Yamakawa K, Tung R, Mahajan A, Shivkumar K. Electrical homogenization of ventricular scar by application of collagenase: a novel strategy for arrhythmia therapy. Circ Arrhythm Electrophysiol 2013; 6:776-83. [PMID: 23873142 DOI: 10.1161/circep.113.000448] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Radiofrequency ablation for ventricular tachycardia is an established therapy. Use of chemical agents for scar homogenization represents an alternative approach. The purpose of this study was to characterize the efficacy of collagenase (CLG) application on epicardial ventricular scar homogenization. METHODS AND RESULTS Myocardial infarcts were created in Yorkshire pigs (n=6) by intracoronary microsphere injection. After 46.6±4.3 days, CLG type 2, type 4, and purified CLG were applied in vitro (n=1) to myocardial tissue blocks containing normal myocardium, border zone, and dense scar. Histopathologic studies were performed to identify the optimal CLG subtype. In vivo high-density electroanatomic mapping of the epicardium was also performed, and border zone and dense scar surface area and late potentials were quantified before and after CLG-4 application (n=5). Of the CLG subtypes tested in vitro, CLG-4 provided the best scar modification and least damage to normal myocardium. During in vivo testing, CLG-4 application decreased border zone area (21.3±14.3 to 17.1±11.1 mm(2), P=0.043) and increased dense scar area (9.1±10.3 to 22.0±20.6 mm(2), P=0.043). The total scar area before and after CLG application was 30.4±23.4 and 39.2±29.5 mm(2), respectively (P=0.08). Late potentials were reduced by CLG-4 application (28.8±21.8 to 13.8±13.1, P=0.043). During CLG-4 application (50.0±15.5 minutes), systolic blood pressure and heart rate were not significantly changed (68.0±7.7 versus 61.8±5.3 mmHg, P=0.08; 77.4±7.3 versus 78.8±6.0 beats per minute, P=0.50, respectively). CONCLUSIONS Ventricular epicardial scar homogenization by CLG-4 application is feasible and effective. This represents the first report on bioenzymatic ablation of arrhythmogenic tissue as an alternative strategy for lesion formation.
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Affiliation(s)
- Daigo Yagishita
- UCLA Cardiac Arrhythmia Center, Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, and Department of Cardiac Anesthesia, University of California, Los Angeles, CA
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Small W, Singhal P, Wilson TS, Maitland DJ. Biomedical applications of thermally activated shape memory polymers. JOURNAL OF MATERIALS CHEMISTRY 2010; 20:3356-3366. [PMID: 21258605 PMCID: PMC3023912 DOI: 10.1039/b923717h] [Citation(s) in RCA: 213] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Shape memory polymers (SMPs) are smart materials that can remember a primary shape and can return to this primary shape from a deformed secondary shape when given an appropriate stimulus. This property allows them to be delivered in a compact form via minimally invasive surgeries in humans, and deployed to achieve complex final shapes. Here we review the various biomedical applications of SMPs and the challenges they face with respect to actuation and biocompatibility. While shape memory behavior has been demonstrated with heat, light and chemical environment, here we focus our discussion on thermally stimulated SMPs.
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Affiliation(s)
- Ward Small
- Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Pooja Singhal
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843, USA
| | - Thomas S. Wilson
- Lawrence Livermore National Laboratory, Livermore, California, 94550, USA
| | - Duncan J. Maitland
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, 77843, USA
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Small W, Buckley PR, Wilson TS, Loge JM, Maitland KD, Maitland DJ. Fabrication and characterization of cylindrical light diffusers comprised of shape memory polymer. JOURNAL OF BIOMEDICAL OPTICS 2008; 13:024018. [PMID: 18465981 PMCID: PMC2637550 DOI: 10.1117/1.2904952] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We developed a technique for constructing light diffusing devices comprised of a flexible shape memory polymer (SMP) cylindrical diffuser attached to the tip of an optical fiber. The devices are fabricated by casting an SMP rod over the cleaved tip of an optical fiber and media blasting the SMP rod to create a light diffusing surface. The axial and polar emission profiles and circumferential (azimuthal) uniformity are characterized for various blasting pressures, nozzle-to-sample distances, and nozzle translation speeds. The diffusers are generally strongly forward-directed and consistently withstand over 8 W of incident IR laser light without suffering damage when immersed in water. These devices are suitable for various endoluminal and interstitial biomedical applications.
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Affiliation(s)
- Ward Small
- Lawrence Livermore National Laboratory, 7000 East Avenue, L-211, Livermore, California 94550, USA.
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Cummings JE, Pacifico A, Drago JL, Kilicaslan F, Natale A. Alternative Energy Sources for the Ablation of Arrhythmias. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2005; 28:434-43. [PMID: 15869678 DOI: 10.1111/j.1540-8159.2005.09481.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jennifer E Cummings
- Department of Cardiovascular Medicine, Section of Pacing and Electrophysiology, The Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA
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10
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Reek S, Geller JC, Schildhaus HU, Mahnkopf D, Mittag J, Klein HU. Catheter Ablation of Ventricular Tachycardia by Intramyocardial Injection of Ethanol in an Animal Model of Chronic Myocardial Infarction. J Cardiovasc Electrophysiol 2004; 15:332-41. [PMID: 15030425 DOI: 10.1046/j.1540-8167.2004.03409.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Direct injection of ethanol into myocardium has been shown to create large, well-demarcated lesions with transmural necrosis in normal ventricular myocardium and in regions of healed myocardial infarction. The aim of this study was to investigate the effects of direct ethanol injection on the inducibility of ventricular tachycardia (VT) in an animal model of chronic myocardial infarction. METHODS AND RESULTS Eight sheep with reproducibly inducible VT underwent an electrophysiologic study 139 +/- 65 days after myocardial infarction. Noncontact mapping was used to analyze induced VT. Fifteen different VTs were targeted for catheter ablation. Ablation was achieved by catheter-based intramyocardial injection of a mixture of 96% ethanol, glycerine, and iopromide (ratio 3:1:1). Direct intramyocardial ethanol injection resulted in noninducibility of any VT 20 minutes after ablation in 7 of 8 animals. Four of 5 animals with initially successful ablation remained noninducible for any VT at follow-up study at least 2 days after the ablation procedure. Microscopic examination revealed homogeneous lesions with interstitial edema, intramural hemorrhage, and myofibrillar degeneration at the lesion border. The lesions were well demarcated from the surrounding tissue by a border zone of neutrophilic infiltration. CONCLUSION Catheter ablation of VT by direct intramyocardial injection of ethanol during the chronic phase of myocardial infarction is feasible. It may be a useful tool for catheter ablation when the area of interest is located deep intramyocardially or subepicardially or when a more regional approach requires ablation of larger amounts of tissue.
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Affiliation(s)
- Sven Reek
- Division of Cardiology, University Hospital Magdeburg, Magdeburg, Germany.
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11
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Reddy VY, Houghtaling C, Fallon J, Fischer G, Farr N, Clarke J, McIntyre J, Sinofsky E, Ruskin JN, Keane D. Use of a Diode Laser Balloon Ablation Catheter to Generate Circumferential Pulmonary Venous Lesions in an Open-Thoracotomy Caprine Model. PACING AND CLINICAL ELECTROPHYSIOLOGY: PACE 2004; 27:52-7. [PMID: 14720155 DOI: 10.1111/j.1540-8159.2004.00385.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrical isolation of the pulmonary veins (PVs) can be curative in certain patients with atrial fibrillation. The ability of a diode laser balloon ablation catheter to isolate PVs was assessed in an open-thoracotomy caprine model system. After a median sternotomy, the left atrial appendage was cannulated in 19 goats. A laser balloon catheter was placed at the PV ostia and used to deliver photonic energy to the periostial tissue. The applications were delivered at 3.7, 4.5, or 5.4 W/cm for 90-150 seconds. Electrical continuity of the PV with the left atrium was assessed using a multielectrode mapping catheter. After a single application of photonic energy, electrical isolation of the PVs was achieved in (70%) 19/27 PVs. However, the success of electrical PV isolation did not correlate with the dose or duration of the applications. When reflectance spectroscopy was utilized to ensure adequate orientation and contact of the laser balloon catheter with the left atrial myocardium, complete PV isolation was achieved in 5/5 veins at 3.5 W/cm for 120 seconds. Pathological examination revealed no PV stenosis, no pericardial damage, minor lung lesions without pleural perforation, minimal endothelial disruption, and, in the presence of adequate heparinization, no endocardial charring or overlying thrombus. Effective isolation of the PVs can be achieved by delivery of a continuous circular beam of photonic energy to ablate the left atrial - pulmonary venous junction. The use of reflectance spectroscopy to provide real-time monitoring of the blanching effect of balloon-tissue contact optimizes lesion delivery.
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Affiliation(s)
- Vivek Y Reddy
- Cardiac Arrhythmia Service, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA.
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12
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Fried NM, Tsitlik A, Rent KC, Berger RD, Lardo AC, Calkins H, Halperin HR. Laser ablation of the pulmonary veins by using a fiberoptic balloon catheter: implications for treatment of paroxysmal atrial fibrillation. Lasers Surg Med 2001; 28:197-203. [PMID: 11295752 DOI: 10.1002/lsm.1038] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Focal sources of paroxysmal atrial fibrillation may be treatable by electrical isolation of the pulmonary veins from the left atrium. A new fiberoptic balloon catheter was tested as an alternative to radiofrequency catheter ablation for creation of circumferential thermal lesions at the pulmonary vein orifice. STUDY DESIGN/MATERIALS AND METHODS In vitro and in vivo experiments were conducted in canine hearts to demonstrate efficacy and optimize ablation dosimetry. Continuous-wave, 1.06-microm, Nd:YAG laser radiation was delivered radially through diffusing optical fiber tips enclosed in a balloon catheter. During in vivo studies, the catheter was placed at the pulmonary vein orifice through a left atrial appendage sheath under X-ray fluoroscopic guidance during an open-chest procedure. Additionally, circumferential lesions in the left atrial appendage were correlated with epicardial electrograms demonstrating elimination of electrical activity. RESULTS The pulmonary veins were successfully ablated by using laser powers of 30--50 W and irradiation times of 60--90 seconds. Transmural, continuous, and circumferential lesions were produced in the pulmonary veins in a single application without evidence of tissue vaporization or endothelial disruption. CONCLUSION Laser ablation by using a fiberoptic balloon catheter may represent a promising alternative to radiofrequency catheter ablation for electrical isolation of the pulmonary veins from the left atrium during treatment of paroxysmal atrial fibrillation. Further development and testing of the fiberoptic catheter is warranted for possible clinical studies.
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Affiliation(s)
- N M Fried
- Department of Biomedical Engineering, The Johns Hopkins University, Baltimore, Maryland 21205, USA.
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13
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Fried NM, Lardo AC, Berger RD, Calkins H, Halperin HR. Linear lesions in myocardium created by Nd:YAG laser using diffusing optical fibers: in vitro and in vivo results. Lasers Surg Med 2001; 27:295-304. [PMID: 11074506 DOI: 10.1002/1096-9101(2000)27:4<295::aid-lsm2>3.0.co;2-t] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVE Linear lesions may be necessary for successful catheter ablation of cardiac arrhythmias such as atrial fibrillation. This study uses laser energy delivered through diffusing optical fibers as an alternative to radiofrequency energy for the creation of linear lesions in cardiac tissue in a single application. STUDY DESIGN/MATERIALS AND METHODS Samples of canine myocardium were placed in a heated, circulating saline bath and irradiated with a 1.06-microm, continuous-wave Nd:YAG laser during in vitro studies. Laser ablation was then performed in vivo on the epicardial surface of the right ventricle during an open-chest procedure by using similar ablation parameters. Laser energy was delivered to the tissue by being diffused radially through flexible optical fiber tips oriented parallel to the tissue surface. Histology and temperature measurements verified transmurality, continuity, and linearity of the lesions. RESULTS Peak tissue temperatures measured in vitro remained low (51 +/- 1 degrees C at the endocardial surface, 61 +/- 6 degrees C in the mid-myocardium, and 55 +/- 6 degrees C at the epicardial surface) with no evidence of tissue charring or vaporization. Lesion dimensions produced in vitro and in vivo were similar (depth, 6 mm; width, 8-10 mm; length, 16-22 mm), demonstrating that tissue perfusion in vivo did not significantly alter the heating. CONCLUSION Long linear lesions, necessary for duplication of the surgical maze procedure during catheter ablation of atrial fibrillation, may be created by using laser radiation delivered through flexible diffusing optical fiber tips. Further development of steerable catheters for endocardial atrial ablation and studies correlating thermal damage zones with electrophysiologic indicators of irreversible conduction block are warranted.
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Affiliation(s)
- N M Fried
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, USA.
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Ware DL, Boor P, Yang C, Gowda A, Motamedi M. Ventricular arrhythmias following thermal damage of epicardial tissue: possible causes and clinical implications. Pacing Clin Electrophysiol 2000; 23:1375-80. [PMID: 11025893 DOI: 10.1111/j.1540-8159.2000.tb00965.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Epicardial heating may be used for ventricular tachycardia (VT) ablation and transmyocardial revascularization. However, the potential risks of thermal epicardial injury, including arrhythmia, have not been fully explored. This study relates the pathologic and arrhythmic sequellae of epicardial heating when applied with a diode laser at varying doses. Acute pathology and dosimetry were determined in a group of normal dogs using 2-3 W over 30-90 seconds. Another group received a similar dose range before undergoing 24-hour monitoring, and electrophysiological testing was done at 4 weeks. In this group, four dogs each received 12 lesions (90-180 J) according to a randomized block design. Another dog received nine lower dose lesions (30-120 J). Acute lesions measured 2.5-8.0-mm wide by 4-8.5-mm deep. Charring and vaporization were common when 3 W were applied over 45 seconds. Within 24 hours, VT with features of abnormal automaticity occurred in all dogs receiving this dose. The dog in whom lower doses induced coagulation only had no VT. Four weeks later, electrophysiological study induced no VT. At this time fibrosis and granulation tissue were organizing the contraction band necrosis seen acutely, and some lesion borders were becoming calcified. No major vessels had been damaged. Abnormal automaticity and VT may occur if thermal damage of the epicardium exceeds coagulation. This could be related to tissue injury caused by sudden water vaporization, and may have clinical relevance given the growing indications for myocardial heating.
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Affiliation(s)
- D L Ware
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, TX 77555-0553, USA.
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