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Measurement bias in activation-recovery intervals from unipolar electrograms

Western, David; Hanson, Ben; Taggart, Peter

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David Western
Wallscourt Fellow in Health Technology

Ben Hanson

Peter Taggart


© the American Physiological Society. The activation-recovery interval (ARI) calculated from unipolar electrograms is regularly used as a convenient surrogate measure of local cardiac action potential durations (APD). This method enables important research bridging between computational studies and in vitro and in vivo human studies. The Wyatt method is well established as a theoretically sound method for calculating ARIs; however, some studies have observed that it is prone to a bias error in measurement when applied to positive T waves. This article demonstrates that recent theoretical and computational studies supporting the use of the Wyatt method are likely to have underestimated the extent of this bias in many practical experimental recording scenarios. This work addresses these situations and explains the measurement bias by adapting existing theoretical expressions of the electrogram to represent practical experimental recording configurations. A new analytic expression for the electrogram’s local component is derived, which identifies the source of measurement bias for positive T waves. A computer implementation of the new analytic model confirms our hypothesis that the bias is systematically dependent on the electrode configuration. These results provide an aid to electrogram interpretation in general, and this work’s outcomes are used to make recommendations on how to minimize measurement error.


Western, D., Hanson, B., & Taggart, P. (2015). Measurement bias in activation-recovery intervals from unipolar electrograms. AJP - Heart and Circulatory Physiology, 308(4), H331-H338.

Journal Article Type Article
Acceptance Date Nov 10, 2014
Publication Date Jan 1, 2015
Deposit Date Sep 17, 2018
Publicly Available Date Sep 17, 2018
Journal American Journal of Physiology - Heart and Circulatory Physiology
Print ISSN 0363-6135
Electronic ISSN 1522-1539
Publisher American Physiological Society
Peer Reviewed Peer Reviewed
Volume 308
Issue 4
Pages H331-H338
Public URL
Publisher URL


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