Contact force and ablation assessment of surgical bipolar radiofrequency clamps in the treatment of atrial fibrillation

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dc.contributor.authorVarzaly, J.A.
dc.contributor.authorChapman, D.
dc.contributor.authorLau, D.H.
dc.contributor.authorEdwards, S.
dc.contributor.authorLouise, J.
dc.contributor.authorEdwards, J.
dc.contributor.authorMahajan, R.
dc.contributor.authorWorthington, M.
dc.contributor.authorSanders, P.
dc.date.issued2018
dc.description.abstractOBJECTIVES: Atrial fibrillation is treated surgically by creating conduction block lesions. Radiofrequency (RF) lesions have reduced efficacy compared to ‘cut-and-sew’. Catheter ablation studies demonstrate a relationship between lesion depth and contact force. We hypothesized that contact force and lesion depth are dependent on design of the bipolar surgical RF clamps. METHODS: Hinged and parallel jaw style RF clamps were studied. Muscle samples were clamped with pressure-sensitive film at increasing tissue thicknesses. Films were analysed determining clamp pressure profiles. A sheep model was utilized for ablation testing using each clamp style until the device indicated transmurality. Separate muscle areas had 1, 2 or 3 burns applied. The muscle was excised, sectioned every 1 cm and stained for lesion depth and fat thickness analysis. RESULTS: Pressure profiling comparing the proximal and distal segments of each clamp style demonstrated only one statistically significant difference in the parallel clamp; the hinged clamp had statistically significant differences (P ≤ 0.03) for all tissue thicknesses. There was no evidence for differences in the proximal lesion depth of both clamps (P = 0.13) but deeper distally in the parallel clamp (10.17 mm vs 8.02 mm, P = 0.003). The logistic regression analysis demonstrated increased odds of transmurality with parallel clamps at 1, 2 or 3 burns (P = 0.03, P = 0.003 and P = 0.002). Every 1 mm increase in overlying fat decreased likelihood of transmurality by 11% (P < 0.05). CONCLUSIONS: The parallel and hinged clamps have different pressure profiles with higher likelihood of transmurality using the parallel clamp. Fat reduces the ability of RF to deliver a transmural lesion. These findings have implications for optimal surgical RF ablation technique.
dc.description.statementofresponsibilityJason A Varzaly, Darius Chapman, Dennis H Lau, Suzanne Edwards, Jennie Louise, James Edwards, Rajiv Mahajan, Michael Worthington, Prashanthan Sanders
dc.identifier.citationInterdisciplinary cardiovascular and thoracic surgery, 2018; 28(1):1-9
dc.identifier.doi10.1093/icvts/ivy191
dc.identifier.issn1569-9293
dc.identifier.issn1569-9285
dc.identifier.orcidLau, D.H. [0000-0001-7753-1318] [0000-0002-1564-439X]
dc.identifier.orcidEdwards, S. [0000-0003-2074-1685]
dc.identifier.orcidLouise, J. [0000-0001-5785-0290]
dc.identifier.orcidMahajan, R. [0000-0003-3375-5568]
dc.identifier.orcidSanders, P. [0000-0003-3803-8429]
dc.identifier.urihttp://hdl.handle.net/2440/116794
dc.language.isoen
dc.publisherOxford University Press
dc.rights© The Author(s) 2018. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/about_us/legal/notices)
dc.source.urihttps://doi.org/10.1093/icvts/ivy191
dc.subjectSurgery; atrial fibrillation; ablation; contact force; lesion; radiofrequency
dc.titleContact force and ablation assessment of surgical bipolar radiofrequency clamps in the treatment of atrial fibrillation
dc.typeJournal article
pubs.publication-statusPublished

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