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Europace Advance Access published online on November 6, 2009
Europace, doi:10.1093/europace/eup351
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Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2009. For permissions please email: journals.permissions@oxfordjournals.org.

CLINICAL RESEARCH

Validation of a classification system to grade fractionation in atrial fibrillation and correlation with automated detection systems

Ross J. Hunter, Ihab Diab, Glyn Thomas, Edward Duncan, Dominic Abrams, Mehul Dhinoja, Simon Sporton, Mark J. Earley and Richard J. Schilling*

Cardiology Research Department, Barts and The London NHS Trust and QMUL, St Bartholomew's Hospital, First Floor Dominion House, 60 Bartholomew Close, West Smithfield, London EC1A 7BE, UK

Aims: We tested application of a grading system describing complex fractionated electrograms (CFE) in atrial fibrillation (AF) and used it to validate automated CFE detection (AUTO).

Methods and results: Ten seconds bipolar electrograms were classified by visual inspection (VI) during ablation of persistent AF and the result compared with offline manual measurement (MM) by a second blinded operator: Grade 1 uninterrupted fractionated activity (defined as segments ≥70 ms) for ≥70% of recording and uninterrupted ≥1 s; Grade 2 interrupted fractionated activity ≥70% of recording; Grade 3 intermittent fractionated activity 30–70%; Grade 4 discrete (<70 ms) complex electrogram (≥5 direction changes); Grade 5 discrete simple electrograms (≤4 direction changes); Grade 6 scar. Grade by VI and MM for 100 electrograms agreed in 89%. Five hundred electrograms were graded on Carto and NavX by VI to validate AUTO in (i) detection of CFE (grades 1–4 considered CFE), and (ii) assessing degree of fractionation by correlating grade and score by AUTO (data shown as sensitivity, specificity, r): NavX ‘CFE mean’ 92%, 91%, 0.56; Carto ‘interval confidence level’ using factory settings 89%, 62%, –0.72, and other published settings 80%, 74%, –0.65; Carto ‘shortest confidence interval’ 74%, 70%, 0.43; Carto ‘average confidence interval’ 86%, 66%, 0.53.

Conclusion: Grading CFE by VI is accurate and correlates with AUTO.

Key Words: AF, Complex fractionated electrograms, CFE, Carto, NavX

* Corresponding author. Tel: +44 207 601 8639, Fax: +44 207 601 8627, Email: r.schilling{at}qmul.ac.uk

Manuscript submitted 13 July 2009. Accepted after revision 13 October 2009.


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