This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/jce.13323. This article is protected by copyright. All rights reserved. The sawtooth EKG pattern of typical atrial flutter is not related to slow conduction velocity at the cavotricuspid isthmus Arunashis Sau, MBBS 1,2 Markus B Sikkel, PhD 1,2 Vishal Luther, MBBS 1,2 Ian Wright, BSc 2 Fernando Guerrero, BSc 3 Michael Koa-Wing, PhD 2 David Lefroy, MBBS 2 Nicholas Linton, PhD 1,2 Norman Qureshi, PhD 2 Zachary Whinnett, PhD 1,2 Phang Boon Lim, PhD 1,2 Prapa Kanagaratnam, PhD 1,2 Nicholas S Peters, MD 1,2 D Wyn Davies, MD 1,2 1 Imperial College London, London, United Kingdom 2 Imperial College Healthcare NHS Trust, Department of Cardiology, London, United Kingdom 3 Boston Scientific, Breakspear Park, Hemel Hempstead, Herts, United Kingdom