Left posterior fascicular block
A left posterior fascicular block 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:
The broad nature of the posterior bundle as well as its dual blood supply makes isolated LPFB rare.
