Middle-aged patient presenting with palpitations and dizziness.

What does the ECG show?

Describe and interpret this ECG



This ECG shows a regular broad complex tachycardia with an RSR’ pattern in V1.

The differential diagnosis could include:

On closer inspection, the ECG demonstrates some classic features of ventricular tachycardia:

  • Northwest axis — QRS is positive in aVR, negative in I and aVF
  • The taller left rabbit ear sign — There is an atypical RBBB pattern in V1, where the left “rabbit ear” is taller than the right
  • Negative QRS complex (R/S ratio < 1) in V6

These findings indicate VT rather than SVT with aberrancy.

  • Taller left rabbit ear = VT

  • Taller right rabbit ear = RBBB


Other factors that increase the likelihood of VT in patients presenting with regular broad complex tachycardia include:

  • Age > 35 (positive predictive value of 85%)
  • Structural heart disease — e.g. IHD, CCF, cardiomyopathy
  • Family history of sudden cardiac death or arrhythmogenic conditions such as HOCMBrugada syndrome or ARVD that are associated with episodes of VT

In any patient with a broad complex rhythm, also consider the possibility of toxic / metabolic conditions such as hyperkalaemia or sodium-channel blockade.

TOP 100 ECG Series

Emergency Physician in Prehospital and Retrieval Medicine in Sydney, Australia. He has a passion for ECG interpretation and medical education | ECG Library |

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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