Fusion Beats

Fusion Beats

A fusion beat occurs when a supraventricular and a ventricular impulse coincide to produce a hybrid complex. It indicates that there are two foci of pacemaker cells firing simultaneously: a supraventricular pacemaker (e.g. the sinus node) and a competing ventricular pacemaker (source of ventricular ectopics).

  • The fusion beats are of intermediate width and morphology to the supraventricular and ventricular complexes.
  • Originally described by William Dressler in 1952

ECG Example

ECG VT Fusion beat capture beat
Fusion beats due to VT – the first of the narrower complexes is a fusion beat (the next two are capture beats)


Fusion beats are seen with:

Related Topics

LITFL Further Reading

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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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