more detailed information about left posterior fascicular block
Last reviewed 01/2018
- the normal left ventricular activation proceeds first down the left bundle branch, and then simultaneously through its two fascicles (left anterior fascicle and left posterior fascicle)
- left posterior fascicular block (LPFB), also
known as left posterior hemiblock, is much less common than left anterior fascicular
block (LAFB) - this is due to a number of factors:
- the posterior fascicle is a thicker structure than the anterior fascicle
- posterior fascile has a dual blood supply
- the anatomic location of the posterior fascicle is away from more turbulent ventricular blood flow
- ECG changes
in LPFB:
- QRS interval <0.12 seconds
- right axis deviation
- rS pattern in the lateral limb leads (I and aVl)
- qR complex in the inferior leads (II, III, and aVf)
- no evidence of right ventricular hypertrophy
- LPFB
is a rare finding
- LPFB is nonspecific for cardiac disease - however coronary artery disease is the most common cause
- other associations for LPFB include hypertensive heart disease, aortic valvular pathology, and fibrocalcific disease of the cardiac skeleton
- LPFB is the least common intraventricular conduction block seen in acute myocardial infarction
- data on established LPFB are insufficient assess prognostic significance
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