Orini, M, Yanni, J, Taggart, P et al. (10 more authors) (2019) Mechanistic insights from targeted molecular profiling of repolarization alternans in the intact human heart. EP Europace, 21 (6). pp. 981-989. ISSN 1099-5129
Abstract
Aims: Action potential duration (APD) alternans is an established precursor or arrhythmia and sudden cardiac death. Important differences in fundamental electrophysiological properties relevant to arrhythmia exist between experimental models and the diseased in vivo human heart. To investigate mechanisms of APD alternans using a novel approach combining intact heart and cellular cardiac electrophysiology in human in vivo.
Methods and results: We developed a novel approach combining intact heart electrophysiological mapping during cardiac surgery with rapid on-site data analysis to guide myocardial biopsies for laboratory analysis, thereby linking repolarization dynamics observed at the organ level with underlying ion channel expression. Alternans-susceptible and alternans-resistant regions were identified by an incremental pacing protocol. Biopsies from these sites (n = 13) demonstrated greater RNA expression in Calsequestrin (CSQN) and Ryanodine (RyR) and ion channels underlying IK1 and Ito at alternans-susceptible sites. Electrical restitution properties (n = 7) showed no difference between alternans-susceptible and resistant sites, whereas spatial gradients of repolarization were greater in alternans-susceptible than in alternans-resistant sites (P = 0.001). The degree of histological fibrosis between alternans-susceptible and resistant sites was equivalent. Mathematical modelling of these changes indicated that both CSQN and RyR up-regulation are key determinants of APD alternans.
Conclusion: Combined intact heart and cellular electrophysiology show that regions of myocardium in the in vivo human heart exhibiting APD alternans are associated with greater expression of CSQN and RyR and show no difference in restitution properties compared to non-alternans regions. In silico modelling identifies up-regulation and interaction of CSQN with RyR as a major mechanism underlying APD alternans.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2019. Published by Oxford University Press on behalf of the European Society of Cardiology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
Keywords: | Arrhythmia mechanisms, Repolarization alternans, Sudden cardiac death, Whole heart cardiac mapping, Molecular profiling, Multi-electrode sock |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Biological Sciences (Leeds) > School of Biomedical Sciences (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 19 Feb 2019 14:22 |
Last Modified: | 25 Jun 2023 21:43 |
Status: | Published |
Publisher: | Oxford University Press |
Identification Number: | 10.1093/europace/euz007 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:142660 |