I44.5

ICD-10-CM Coding Rules

• I44.5

Approximate Synonyms

• Left posterial fascicular hemiblock heart rhythm)

• Left posterior hemiblock

Clinical Information

• An impairment of transmission of the cardiac electrical impulse along the fibers of the left posterior fascicle. In pure left posterior fascicular block lpfb), the impulse emerges from the unblocked anterosuperior division, thus producing small q waves in leads ii, iii, and avf. Thereafter, the impulse moves through the electrically predominant left ventricle in an inferior and rightward direction, thus explaining the s waves in leads i and avl as well as the r waves in leads ii, iii, and avf.

• An impairment of transmission of the cardiac electrical impulse along the fibers of the left posterior fascicle. In pure left posterior fascicular block lpfb), the impulse emerges from the unblocked anterosuperior division, thus producing small q waves in leads ii, iii, and avf. Thereafter, the impulse moves through the electrically predominant left ventricle in an inferior and rightward direction, thus explaining the s waves in leads i and avl as well as the r waves in leads ii, iii, and avf. Left posterior fascicular block is characterized by all of the following: right-axis deviation with frontal qrs axis between +90 degrees and +180 degrees; rs in leads i and avl and qr in inferior leads q waves 40 ms) qrs duration <120 ms.

Details

• I44.5 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.

• The 2023 edition of ICD-10-CM I44.5 became effective on October 1, 2022.

• This is the American ICD-10-CM version of I44.5 – other international versions of ICD-10 I44.5 may differ.