Delta Wave

Delta Wave Overview

The Delta wave is a slurred upstroke in the QRS complex often associated with a short PR interval. It is most commonly associated with pre-excitation syndrome such as WPW.

The characteristic ECG findings in the Wolff-Parkinson-White syndrome are:

  • Short PR interval (< 120ms)
  • Broad QRS (> 100ms)
  • A slurred upstroke to the QRS complex (the delta wave)

In 1930, Wolff, Parkinson, and White erroneously thought that the wide QRS complex was caused by a type of bundle-branch block. This was corrected in 1933 by Wolferth and Wood.

in 1944 Segers PM, Lequime J and Denolin proposed the symbol Δ to represent the triangle shape at the base of the upsloping QRS complex. They described the ‘… deformation of the PQ segment is the result of a supplementary electrical deflection that we propose to call Δ‘ . This became more commonly described as the ‘delta wave

ECG examples of Delta Waves
Delta wave

Negative delta waves (e.g. seen in lead aVR)

Further reading


ECG Library Basics

Advanced Reading



LITFL Further Reading




Emergency physician MA (Oxon) MBChB (Edin) FACEM FFSEM with a passion for rugby; medical history; medical education; and informatics. Asynchronous learning #FOAMed evangelist. Co-founder and CTO of Life in the Fast lane | Eponyms | Books | vocortex |

MBBS (UWA) CCPU Emergency Medicine Advanced Trainee based in Melbourne, Australia. Co-author of the LITFL ECG Library. Likes Ultrasound, Echo, ECGs, and anything and everything with caffeine. Part of the 2021 ANZCEN Clinician Educator Incubator Programme | @rob_buttner | ECG Library |

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