what is a fascicular block
Left anterior fascicular block, sometimes abbreviated LAFB, is a cardiac condition, distinguished from left bundle branch block.It is caused by only the anterior half of the left bundle branch being defective. It is manifested on the ECG by left axis deviation.ormal activation of the left ventricle proceeds down the left bundle branch, which consist of three fascicles, the left anterior fascicle, the left posterior fascicle, and the septal fascicle.