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v1.0.0
ICD-10 Guide
DiagnosesLeft Anterior Fascicular Block

Left Anterior Fascicular Block

ICD-10 Coding for Left Anterior Fascicular Block(I44.4, I45.2)

PRIMARY SPECIALTYCardiology
COMPLEXITYHigh
LAST UPDATED09/15/2025
Sam Tuffun, PT, DPT
Physical Therapist | Medical Coding & Billing Contributor

Diagnosis Overview

What is Left Anterior Fascicular Block?
Essential facts and insights about Left Anterior Fascicular Block

Key Clinical Considerations:

  • Symptoms may include syncope, palpitations, or fatigue.
  • Key diagnostic tests include ECG showing left axis deviation and QRS duration > 120 ms.
  • Physical exam may reveal bradycardia or signs of heart failure.

Clinical Information

Clinical Criteria & Documentation Requirements

  • Document patient's symptoms, ECG findings, and any associated conditions.
  • Use specific terms like 'left anterior fascicular block' and 'left axis deviation'.
  • Example: 'Patient presents with syncope and ECG shows left anterior fascicular block.'

Coding Guidelines

Usage Guidelines & Examples

  • Follow guidelines for left bundle branch block vs. left anterior fascicular block.
  • Common errors include misclassifying the block type.

Code Exclusions

Important Exclusions

  • Right bundle branch block, complete heart block.
  • I44.0 (Unspecified bundle branch block)

Related ICD-10 Codes

Primary Codes
I44.1
Left anterior fascicular block
Ancillary Codes
Z86.79
Differential Codes
I44.7
V6
, absent Q waves in lateral leads.

Related CPT Codes

CPT codes will be available in a future update.

Specialty Focus

Primary Specialty

Cardiology

Specialty Applications

  • Adults with cardiovascular disease, particularly those with hypertension or ischemic heart disease.
  • Cardiology clinics and emergency departments.

Coding Complexity

High Complexity

This diagnosis requires careful attention to:

  • Comprehensive clinical documentation
  • Accurate code selection based on clinical criteria
  • Proper exclusion considerations
  • Specialty-specific coding guidelines

Documentation

Documentation Templates

Billing Information

Billing Considerations

  • Ensure proper documentation for billing
  • Verify code specificity requirements
  • Check for any additional codes needed
  • Review payer-specific guidelines

Common Issues

  • Insufficient clinical documentation
  • Incorrect code selection
  • Missing supporting diagnoses
  • Timing and frequency documentation

Frequently Asked Questions

What are the documentation requirements?

Document symptoms, ECG findings, and any relevant history.

What are the billing considerations?

Ensure accurate coding to reflect the diagnosis and any associated conditions.