For a patient with Right Bundle Branch Block (RBBB) undergoing Coronary Artery Bypass Grafting (CABG), is it better to place a temporary pacing wire and assess the need for pacing after 5-7 days, or to prophylactically place a permanent epicardial wire during surgery?

Management of Temporary vs. Permanent Pacing Wires for RBBB Patients Undergoing CABG

For patients with RBBB undergoing CABG, placement of temporary epicardial pacing wires with assessment after 5-7 days is recommended rather than prophylactic permanent epicardial wire placement during surgery. 1

Evidence-Based Approach to Pacing in CABG Patients with RBBB

Initial Management

• The 2019 ACC/AHA/HRS guidelines provide a Class IIa, Level B-NR recommendation for routine placement of temporary epicardial pacing wires in all patients undergoing isolated CABG 1, 2
• This recommendation applies regardless of pre-existing conduction disorders, including RBBB

Post-Operative Assessment Period

• Observe for 5-7 days post-CABG to determine if permanent pacing is needed 1
• Permanent pacing is only recommended if new postoperative sinoatrial node dysfunction or atrioventricular block develops with:
  • Persistent symptoms OR
  • Hemodynamic instability that doesn't resolve 1

Risk Factors for Requiring Post-CABG Pacing

Three major predictors have been identified for requiring pacing after CABG:

1. Pre-existing arrhythmias (especially bundle branch blocks) 3, 4
2. Need for pacing when separating from cardiopulmonary bypass 3, 4
3. Use of antiarrhythmics when leaving the operating room 3

Why Temporary Wires Are Preferred Over Prophylactic Permanent Wires

Low Incidence of Requiring Permanent Pacing

• Only 2.9-8.6% of CABG patients require pacing postoperatively 3, 4
• When excluding patients with the three major risk factors above, the need for pacing drops to just 1.1-2.6% 3, 4

Avoiding Unnecessary Procedures

• Prophylactic permanent epicardial wire placement would subject >90% of patients to an unnecessary intervention
• Temporary wires allow for assessment of true need before committing to permanent pacing

Safety Considerations

• While temporary wires have rare complications (bleeding, tamponade), these risks are outweighed by the benefit of having temporary pacing available when needed 1, 5
• Prophylactic permanent wire placement would expose all patients to risks of a permanent device when most won't need it

Special Considerations for RBBB Patients

• While RBBB increases risk of requiring pacing post-CABG, most RBBB patients still won't need permanent pacing
• The 5-7 day observation period allows for:
  • Resolution of transient conduction disturbances
  • Clear identification of patients with persistent pacing needs
  • Avoidance of unnecessary permanent device implantation

Conclusion

The evidence strongly supports placing temporary epicardial pacing wires during CABG in patients with RBBB, followed by a 5-7 day assessment period to determine if permanent pacing is truly needed, rather than prophylactic permanent epicardial wire placement during the initial surgery.