Rahul Sharma (Editor)

Left posterior fascicular block

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Specialty
  
cardiology

ICD-10
  
I44.5

A left posterior fascicular block (LPFB) is a condition where the left posterior fascicle, which travels to the inferior and posterior portion of the left ventricle, does not conduct the electrical impulses from the atrioventricular node. The wave-front instead moves more quickly through the left anterior fascicle and right bundle branch, leading to a right axis deviation seen on the ECG.

The American Heart Association has defined a LPFB as:

  • Frontal plane axis between 90° and 180° in adults
  • rS pattern in leads I and aVL
  • qR pattern in leads III and aVF
  • QRS duration less than 120 ms
  • The broad nature of the posterior bundle as well as its dual blood supply makes isolated LPFB rare.

    References

    Left posterior fascicular block Wikipedia