ECG Case 117

ECG of a 14yr old female who presents following an episode of palpitations and associated dizziness.

ECG Case 117 LITFL Top 100 EKG

Describe and interpret this ECG



  • 110-115 bpm


  • Regular
  • Sinus rhythm


  • Normal


  • PR – Short (80ms)
  • QRS – Prolonged (120ms)
  • QT – 340ms (QTc Bazett 460 ms)


  • ST Elevation leads aVR, V1-2
  • ST Depression leads I, II, III, aVF, V4-6


  • Delta waves best seen inferolaterally
  • T wave inversion leads I, II, III, aVF, V3-6
  • ‘Pseudo’ left ventricular hypertrophy
    • Prominent R waves leads I, II, III, aVF, V4-6
    • Deep S waves leads aVR, aVL, V1-2


  • Wolff-Parkinson-White syndrome
    • Right anteroseptal pathway – using Arruda algorithm
    • Voltage & ST/T changes secondary to pre-excitation
    • Patient requires referral for an EP study.


The right anteroseptal pathway can be difficult to ablate due to the close proximity of the AV node and risk of AV nodal injury during ablation.

Cryothermal ablation and careful mapping may be required rather than RF ablation. A more detailed review of septal accessory pathways and ablation techniques can be found here:

There are two commonly used algorithms to identify accessory pathway location from the surface ECG, the Arruda algorithm and Milstein algorithm. You can also download a free app called EP Mobile which incorporates both algorithm’s in addition to lots of other useful EP formulas (iTunes or Google play)

Arruda algorithm
Milstein algorithm
Milstein algorithm WPW

Milstein S et al. An algorithm for the electrocardiographic localization of accessory pathways in the Wolff-Parkinson-White syndrome. Pacing Clin Electrophysiol. 1987 May;10(3 Pt 1):555-63

TOP 150 ECG Series

Emergency Medicine Specialist MBChB FRCEM FACEM. Medical Education, Cardiology and Web Based Resources | @jjlarkin78 | LinkedIn |

One comment

  1. Question about ECG case 117. Somehow I initially missed the WPW and called it a LBBB with positive Scarbossa in V3. Can WPW and a LBBB exist together? If so, does Scarbossa’s criteria still apply?

    Thank you for these ECGs, they’re truly making me better.

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