2025 ICD-10-CM Diagnosis Code I44.4

by

Left anterior fascicular block

  • I44.4 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
  • The 2025 edition of ICD-10-CM I44.4 became effective on October 1, 2024.
  • This is the American ICD-10-CM version of I44.4 – other international versions of ICD-10 I44.4 may differ.

ICD-10-CM Coding Rules

  • I44.4 is not usually sufficient justification for admission to an acute care hospital when used a principal diagnosis.

The following code(s) above I44.4 contain annotation back-references

 that may be applicable to I44.4:

  • I00-I99  Diseases of the circulatory system

Approximate Synonyms

  • Left anterior fascicular hemiblock (heart rhythm)
  • Left anterior hemiblock

Clinical Information

  • An impairment of transmission of the cardiac electrical impulse along the fibers of the left anterior fascicle. In left anterior fascicular block (lafb) the posteroinferior regions of the left ventricular endocardium are activated abnormally before the anterosuperior left ventricular area. After emerging from the posteroinferior division of the left bundle branch, the impulse first propagates in an inferior, rightward, and usually anterior direction for a short period of time. This orientation is responsible for the small q waves in leads 1 and avl and for the r waves in leads ii, iii, and avf.
  • An impairment of transmission of the cardiac electrical impulse along the fibers of the left anterior fascicle. In left anterior fascicular block (lafb) the posteroinferior regions of the left ventricular endocardium are activated abnormally before the anterosuperior left ventricular area. After emerging from the posteroinferior division of the left bundle branch, the impulse first propagates in an inferior, rightward, and usually anterior direction for a short period of time. This orientation is responsible for the small q waves in leads i and avl and for the r waves in leads ii, iii, and avf.
  • An impairment of transmission of the cardiac electrical impulse along the fibers of the left anterior fascicle. It is characterized by all of the following: left-axis deviation with frontal qrs axis between -45 degrees and -90 degrees; q wave in lead avl; rs in inferior leads ; qrs duration is <120 ms.

ICD-10-CM I44.4 is grouped within Diagnostic Related Group(s) (MS-DRG v42.0):

  • 308 Cardiac arrhythmia and conduction disorders with mcc
  • 309 Cardiac arrhythmia and conduction disorders with cc
  • 310 Cardiac arrhythmia and conduction disorders without cc/mcc

Convert I44.4 to ICD-9-CMCode History

  • 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
  • 2017 (effective 10/1/2016): No change
  • 2018 (effective 10/1/2017): No change
  • 2019 (effective 10/1/2018): No change
  • 2020 (effective 10/1/2019): No change
  • 2021 (effective 10/1/2020): No change
  • 2022 (effective 10/1/2021): No change
  • 2023 (effective 10/1/2022): No change
  • 2024 (effective 10/1/2023): No change
  • 2025 (effective 10/1/2024): No change

Diagnosis Index entries containing back-references to I44.4:

  • Block, blocked
    • bundle-branch (complete) (false) (incomplete) I45.4
      • leftI44.7
        • hemiblockI44.60
          • anterior I44.4
    • fascicular (left) I44.60
      • anterior I44.4
error: Content is protected !!