Flummoxing Familial Fibrillation

aka ECG Exigency 009

An 18-year old female presents to ED with sudden onset of rapid, irregular palpitations and is found to be in fast atrial fibrillation. She denies chest pain or shortness of breath, has no significant past medical history and is not taking any prescription medications or illicit drugs.

She has an interesting family history. Her mother, brother and maternal grandfather have all suffered previous episodes of paroxysmal atrial fibrillation. She had an uncle who died of a sudden cardiac arrest at the age of 30 and a sister who died in infancy from presumed sudden infant death syndrome (SIDS).

She undergoes electrical cardioversion and successfully reverts to sinus rhythm. CXR is unremarkable. Bloods reveal normal levels of potassium, magnesium, calcium and TSH.

Her ECG looks something like this:

ECG Exigency 009 schimpf


Q1. What are the main abnormalities on the ECG?

Answer and Interpretation

The most striking abnormalities on the ECG are:

  • An extremely short QT interval (240ms at a heart rate of 65 bpm = QTc 250ms)
  • Virtually absent ST segments (the end of the QRS complex merges with the start of the T wave)
  • Very tall, narrow, symmetrically peaked T waves in the precordial leads

Q2. What is the likely diagnosis?

Answer and Interpretation

The combination of…

  • a young patient presenting with atrial fibrillation
  • a family history of paroxysmal AF
  • a family history of sudden cardiac death / SIDS
  • an ECG showing extremely short QT interval and peaked T waves

…suggestive of congenital short QT syndrome (SQTS)

Q3. What other conditions may cause a similar ECG appearance?

Answer and Interpretation

QT shortening on the ECG may be due to:

Peaked T waves on the ECG may be due to:


Cardiovascular curveball 700



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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