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Thermodynamic properties of atrial fibrillation cryoablation: a model-based approach to improve knowledge on energy delivery.

ABSTRACT: The objective of this study is to describe a suitable model of atrial fibrillation cryoablation thermodynamic properties. Three different thermal loads were applied to a cylindrical copper element simulating the cryoprobe, thermally coupled with a Peltier stack producing the freezing effect, and in contact with a bovine liver sample. Thermal events occurring inside the samples were measured using mirror image technique. Heat subtracted flux during ice formation and minimum temperature measured at probe-tissue interface were, respectively, 1.33 W cm-2 and -27.8°C for Sample#0, 1.88 W cm-2 and -35.6°C for Sample#1 and 1.82 W cm-2 and 1.44 W cm-2 before and after the ice trigger, respectively, and -29.3°C for Sample#2. Ice trigger temperature was around -8.5°C for Sample#0 and Sample#2, and -10.4°C for Sample#1. In all the investigated samples, ice front penetration was proportional to the square root of time and its velocity depended on the heat flux subtracted. The fraction of the useful energy spent for ice formation was less than 60% for Sample#0, and about 80% for Sample#1 and for Sample#2, before the reduction of the removed heat flux. Freezing time exceeding a cut-off, according to the heat subtracted flux, does not improve the procedure effectiveness and is detrimental to the surrounding tissues.

SUBMITTER: Giaretto V

PROVIDER: S-EPMC6769315 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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Thermodynamic properties of atrial fibrillation cryoablation: a model-based approach to improve knowledge on energy delivery.

Giaretto Valter V Ballatore Andrea A Passerone Claudio C Desalvo Paolo P Matta Mario M Saglietto Andrea A De Salve Mario M Gaita Fiorenzo F Panella Bruno B Anselmino Matteo M

Journal of the Royal Society, Interface 20190918 158

The objective of this study is to describe a suitable model of atrial fibrillation cryoablation thermodynamic properties. Three different thermal loads were applied to a cylindrical copper element simulating the cryoprobe, thermally coupled with a Peltier stack producing the freezing effect, and in contact with a bovine liver sample. Thermal events occurring inside the samples were measured using mirror image technique. Heat subtracted flux during ice formation and minimum temperature measured a ...[more]

PMID: 31530136

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Project description:Background: There is no validated tool to assess patients' knowledge of oral anticoagulant therapy in atrial fibrillation in China. Methods: Using a standard translation program, the Jessa Atrial fibrillation Knowledge Questionnaire (JAKQ) was translated into Chinese. The reliability of the JAKQ was assessed by internal consistency (Cronbach's α coefficient), repeatability (test-retest reliability), and sensitivity tests. Effectiveness was assessed by hypothesizing that a lower JAKQ score was a risk factor for bleeding. A total of 447 patients with atrial fibrillation (AF) who were hospitalized between July 2019 and December 2021 were studied and followed up. Participants were followed up 1, 3, 6, and 12 months after enrollment. Bleeding during follow-up was recorded. Data were obtained from hospital databases and telephone follow-up. Result: A total of 447 patients with AF completed JAKQ. The mean age of patients was 67.7 ± 10.2 years. The median JAKQ score was 31.3% (12.5-43.8). The Cronbach's α coefficient of JAKQ was 0.616-0.637, and the test-retest reliability value was 0.902 (p < 0.001). Multivariate logistic regression showed that the higher knowledge level of AF was associated with secondary education or above, an income of more than 2000 yuan, and a history of AF of more than 1 year. Bleeding was associated with a lower JAKQ score, hypertension, and a history of bleeding. Non-bleeding patients on VKA had a better understanding of how often INR should be monitored and what to do if an OAC dose was missed. Conclusion: The Chinese version of JAKQ shows good reliability and validity, indicating that it is a valuable tool for AF and oral anticoagulation (OAC) knowledge assessment. It can be used in clinical practice to guide educational activities and improve the effectiveness and safety of treatment. It was shown that Chinese patients with AF have insufficient knowledge about AF and OAC. Lower JAKQ scores are associated with bleeding, so targeted education is necessary. Targeted educational efforts should focus on patients recently diagnosed with AF and those with lower formal education and income.

Dataset Information

Thermodynamic properties of atrial fibrillation cryoablation: a model-based approach to improve knowledge on energy delivery.

Publications

Thermodynamic properties of atrial fibrillation cryoablation: a model-based approach to improve knowledge on energy delivery.

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