Why is a pacemaker (permanent artificial cardiac pacemaker) needed after Transcatheter Aortic Valve Replacement (TAVR)?

Why Pacemakers Are Needed After TAVR

Permanent pacemakers are required after TAVR when patients develop new atrioventricular block associated with symptoms or hemodynamic instability that does not resolve, due to mechanical trauma to the cardiac conduction system during valve deployment. 1

Anatomical Basis for Conduction Disturbances

• The aortic valve is in close anatomical proximity to critical conduction structures:

  • Atrioventricular (AV) node
  • Bundle of His
  • Left bundle branch

• During TAVR, mechanical compression of these structures can occur due to:

  • Direct pressure from the prosthetic valve frame
  • Edema from procedural trauma
  • Calcium displacement from the native valve

Incidence and Types of Conduction Abnormalities

• New conduction disturbances occur in a significant number of TAVR patients:

  • New left bundle branch block (LBBB): 19-55% of patients 1
  • High-degree AV block requiring pacemaker: approximately 10% of patients 1
  • Overall pacemaker implantation rate: 12.5% with balloon-expandable valves 2

• Self-expanding valves have higher pacemaker implantation rates than balloon-expandable valves (15.9% vs 3.7%) 3

Risk Factors for Requiring a Pacemaker

Pre-procedural factors:

• Pre-existing right bundle branch block (RBBB) - increases risk 26-fold 1, 4
• Increased age 2
• First-degree AV block

Procedural factors:

• Larger valve size 2
• Greater valve oversizing 2
• Moderate or severe annular calcification 2
• Implantation depth >6 mm 2
• Self-expanding valve design 3

Timing of Conduction Disturbances

• Immediate: During valve deployment
• Early: Within 48 hours post-procedure
• Delayed: Beyond 48 hours or after discharge (occurs in ~10% of patients) 1

Indications for Permanent Pacemaker After TAVR

According to ACC/AHA/HRS guidelines:

1. Class I recommendation (strong): New atrioventricular block associated with symptoms or hemodynamic instability that does not resolve 1

2. Class IIa recommendation (reasonable): Careful surveillance for bradycardia in patients with new persistent bundle branch block 1

3. Class IIb recommendation (may be considered): Implantation of a permanent pacemaker in patients with new persistent LBBB 1

Management Algorithm

1. Pre-TAVR Assessment:

   • Identify high-risk patients (pre-existing RBBB, first-degree AV block)
   • Discuss potential need for pacemaker and obtain consent

2. Intra-procedural Management:

   • Place temporary pacemaker via right internal jugular vein for high-risk patients
   • Monitor for conduction disturbances during valve deployment

3. Post-TAVR Monitoring and Decision-Making:

   • For patients with new high-grade AV block:

     • Maintain temporary pacemaker for at least 24 hours
     • If persistent or recurrent, implant permanent pacemaker before discharge 1

   • For patients with new LBBB or PR/QRS prolongation ≥20ms:

     • Continue monitoring for at least 24 hours
     • Consider rapid atrial pacing test (absence of Wenckebach AV block at rates up to 120 bpm has 98.7% negative predictive value for needing a pacemaker) 3
     • Monitor for 14 days post-discharge with ambulatory monitoring 1

   • For patients with normal conduction or unchanged pre-existing conduction abnormalities:

     • Can be considered for early discharge without extended monitoring 1

Clinical Outcomes

• Permanent pacemaker implantation after TAVR with SAPIEN 3 valve was not associated with increased 5-year mortality or rehospitalization 2
• However, patients with new pacemakers had a decline in left ventricular ejection fraction at 1 year that persisted at 5 years 2
• Only about half of patients with a new pacemaker will be pacemaker-dependent at follow-up 1

Key Pitfalls to Avoid

• Failing to identify high-risk patients (especially those with pre-existing RBBB)
• Premature removal of temporary pacing in patients with new conduction abnormalities
• Neglecting to monitor for delayed high-grade AV block after discharge
• Overlooking modifiable factors that could reduce pacemaker rates (valve oversizing, implantation depth)