Document Detail


Three potential mechanisms for failure of high intensity focused ultrasound ablation in cardiac tissue.
MedLine Citation:
PMID:  22322367     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: High intensity focused ultrasound (HIFU) has been introduced for treatment of cardiac arrhythmias because it offers the ability to create rapid tissue modification in confined volumes without directly contacting the myocardium. In spite of the benefits of HIFU, a number of limitations have been reported, which hindered its clinical adoption.
METHODS AND RESULTS: In this study, we used a multimodal approach to evaluate thermal and nonthermal effects of HIFU in cardiac ablation. We designed a computer controlled system capable of simultaneous fluorescence mapping and HIFU ablation. Using this system, linear lesions were created in isolated rabbit atria (n=6), and point lesions were created in the ventricles of whole-heart (n=6) preparations by applying HIFU at clinical doses (4-16 W). Additionally, we evaluate the gap size in ablation lines necessary for conduction in atrial preparations (n=4). The voltage sensitive dye di-4-ANEPPS was used to assess functional damage produced by HIFU. Optical coherence tomography and general histology were used to evaluate lesion extent. Conduction block was achieved in 1 (17%) of 6 atrial preparations with a single ablation line. Following 10 minutes of rest, 0 (0%) of 6 atrial preparations demonstrated sustained conduction block from a single ablation line. Tissue displacement of 1 to 3 mm was observed during HIFU application due to acoustic radiation force along the lesion line. Additionally, excessive acoustic pressure and high temperature from HIFU generated cavitation, causing macroscopic tissue damage. A minimum gap size of 1.5 mm was found to conduct electric activity.
CONCLUSIONS: This study identified 3 potential mechanisms responsible for the failure of HIFU ablation in cardiac tissues. Both acoustic radiation force and acoustic cavitation, in conjunction with inconsistent thermal deposition, can increase the risk of lesion discontinuity and result in gap sizes that promote ablation failure.
Authors:
Jacob I Laughner; Matthew S Sulkin; Ziqi Wu; Cheri X Deng; Igor R Efimov
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Publication Detail:
Type:  Evaluation Studies; Journal Article; Research Support, N.I.H., Extramural     Date:  2012-02-09
Journal Detail:
Title:  Circulation. Arrhythmia and electrophysiology     Volume:  5     ISSN:  1941-3084     ISO Abbreviation:  Circ Arrhythm Electrophysiol     Publication Date:  2012 Apr 
Date Detail:
Created Date:  2012-04-18     Completed Date:  2012-06-12     Revised Date:  2013-06-26    
Medline Journal Info:
Nlm Unique ID:  101474365     Medline TA:  Circ Arrhythm Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  409-16     Citation Subset:  IM    
Affiliation:
Department of Biomedical Engineering, Washington University in Saint Louis, MO 63130-4899, USA.
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MeSH Terms
Descriptor/Qualifier:
Acoustics
Animals
Equipment Failure*
Heart Atria / surgery*
Heart Ventricles / surgery*
High-Intensity Focused Ultrasound Ablation / instrumentation*,  methods*
Hot Temperature
Mechanical Processes
Models, Animal
Rabbits
Grant Support
ID/Acronym/Agency:
R01 EB008999/EB/NIBIB NIH HHS; R01 EB008999/EB/NIBIB NIH HHS; R01 HL067322-08/HL/NHLBI NIH HHS; R01 HL085369-04/HL/NHLBI NIH HHS; R21 HL108617-01/HL/NHLBI NIH HHS
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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