Is left anterior fascicular block (LAFB) a contraindication for surgery?

Left Anterior Fascicular Block and Surgery

Left anterior fascicular block (LAFB) alone is not a contraindication for surgery according to current guidelines. 1

Understanding LAFB in the Perioperative Context

LAFB is a conduction abnormality affecting the left anterior fascicle of the left bundle branch. Major cardiac guidelines from the American College of Cardiology, American Heart Association, and Heart Rhythm Society do not list isolated LAFB as a condition requiring special management before surgery 1. This indicates that LAFB by itself does not increase perioperative risk.

Clinical Considerations

Isolated LAFB

• No special intervention is needed for isolated LAFB before non-cardiac surgery 1
• No prophylactic temporary pacing is required
• Regular perioperative cardiac monitoring is sufficient

LAFB with Other Conduction Abnormalities

• When LAFB occurs with right bundle branch block (bifascicular block):
  • Case-by-case evaluation is recommended
  • Consider temporary pacing wires during surgery if the bifascicular block is new or indeterminate 1
  • The risk of developing complete heart block is higher in this scenario

LAFB in Specific Surgical Settings

• For cardiac surgery:

  • Temporary epicardial pacing wires are routinely placed regardless of LAFB status 1
  • This is standard practice for all cardiac surgeries

• For non-cardiac surgery:

  • The 2018 ACC/AHA/HRS guideline specifically states that routine prophylactic temporary transvenous pacing should not be performed in patients with LBBB who require pulmonary artery catheterization 2
  • This recommendation can be reasonably extended to LAFB, which is a less severe conduction abnormality than LBBB

Important Caveats

1. Monitoring Requirements:

   • While not a contraindication, patients with LAFB should have appropriate cardiac monitoring during surgery
   • Transcutaneous pacing pads may be reasonable for patients at high risk for intraoperative bradycardia 2

2. Special Anatomical Considerations:

   • In patients with congenital heart disease like atrioventricular septal defect (AVSD), the atrioventricular node is typically displaced inferiorly and associated with relative hypoplasia of the left anterior fascicle 2
   • These patients may require more careful evaluation, but LAFB itself remains not a contraindication

3. Rare Complications:

   • While extremely uncommon, there have been isolated case reports of progression to higher-degree AV block during surgery in patients with bifascicular block (RBBB + LAFB) 3
   • These rare events do not change the overall guideline recommendations but emphasize the importance of monitoring

Conclusion

Based on current guidelines, isolated LAFB is not a contraindication for surgery. Standard perioperative cardiac monitoring is sufficient, with no need for prophylactic pacing unless LAFB is part of a more complex conduction disorder pattern.