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


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 > or =70 ms) for > or =70% of recording and uninterrupted > or =1 s; Grade 2 interrupted fractionated activity > or =70% of recording; Grade 3 intermittent fractionated activity 30-70%; Grade 4 discrete (<70 ms) complex electrogram (> or =5 direction changes); Grade 5 discrete simple electrograms (< or =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.


CONCLUSIONS
Grading CFE by VI is accurate and correlates with AUTO.
Hunter
Ross J
RJ
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, UK.
Diab
Ihab
I
Thomas
Glyn
G
Duncan
Edward
E
Abrams
Dominic
D
Dhinoja
Mehul
M
Sporton
Simon
S
Earley
Mark J
MJ
Schilling
Richard J
RJ
D000465:Algorithms; D001281:Atrial Fibrillation / Q000145:classification* / Q000175:diagnosis*; D018780:Body Surface Potential Mapping / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic