TY - JOUR
T1 - Linear lesions in myocardium created by Nd:YAG laser using diffusing optical fibers
T2 - In vitro and in vivo results
AU - Fried, Nathaniel M.
AU - Lardo, Albert C.
AU - Berger, Ronald D.
AU - Calkins, Hugh
AU - Halperin, Henry R.
PY - 2000
Y1 - 2000
N2 - 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-μm, 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°C at the endocardial surface, 61 ± 6°C in the mid-myocardium, and 55 ± 6°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. (C) 2000 Wiley-Liss, Inc.
AB - 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-μm, 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°C at the endocardial surface, 61 ± 6°C in the mid-myocardium, and 55 ± 6°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. (C) 2000 Wiley-Liss, Inc.
KW - Ablation
KW - Atrial fibrillation
KW - Catheter
KW - Laser
KW - Linear
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U2 - 10.1002/1096-9101(2000)27:4<295::AID-LSM2>3.0.CO;2-T
DO - 10.1002/1096-9101(2000)27:4<295::AID-LSM2>3.0.CO;2-T
M3 - Article
C2 - 11074506
AN - SCOPUS:0033783375
SN - 0196-8092
VL - 27
SP - 295
EP - 304
JO - Lasers in Surgery and Medicine
JF - Lasers in Surgery and Medicine
IS - 4
ER -