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)

Causes

Fusion beats are seen with:



Advanced Reading

Online

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LITFL Further Reading

ECG LIBRARY 700

ECG LIBRARY

Electrocardiogram

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) 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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