ECG Case 013

Middle-aged patient presenting with palpitations and dizziness. What does the ECG show?

TOP 100 ECG QUIZ LITFL 013

Describe and interpret this ECG

ECG ANSWER and INTERPRETATION

Diagnosis

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.

ECG VT Taller left rabbit ear V1
  • Taller left rabbit ear = VT

RBBB-typical-morphology-300x123
  • Taller right rabbit ear = RBBB

CLINICAL PEARLS

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 ARVC 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 |

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