At what heart rate is a permanent pacemaker recommended after Transcatheter Mitral Valve Replacement (TMVR) and what interventions are necessary?

Permanent Pacemaker Implantation After Transcatheter Valve Replacement: Indications and Interventions

Permanent pacemaker implantation is strongly recommended for patients who develop persistent high-grade AV block after transcatheter valve replacement that does not resolve before discharge. 1

Heart Rate Thresholds and Indications for Permanent Pacemaker

Absolute Indications for Permanent Pacemaker:

• Persistent complete heart block that does not resolve within 24 hours 1
• Symptomatic bradycardia of any severity 1
• High-grade AV block (Mobitz type II or higher) that persists 1
• Recurrent episodes of transient high-grade AV block during hospitalization, regardless of symptoms 1

High-Risk Features Requiring Closer Monitoring:

• Pre-existing RBBB: Highest risk group with up to 24% chance of developing high-degree AV block 1, 2
• New LBBB with PR/QRS prolongation ≥20 ms: Requires continued monitoring 1
• Transient complete heart block during valve deployment: Requires at least 24 hours of monitoring 1

Management Algorithm Based on Conduction Disturbances

1. Patients with Persistent Complete Heart Block:

• Maintain temporary pacemaker for at least 24 hours to assess for conduction recovery
• If heart block persists, proceed with permanent pacemaker implantation before discharge 1

2. Patients with Pre-existing RBBB:

• Highest risk group (up to 24% risk of high-degree AV block) 1, 2
• If they develop any transient or persistent high-grade AV block, permanent pacemaker implantation is indicated in vast majority of cases 1
• Maintain transvenous pacing ability with continuous cardiac monitoring for at least 24 hours 1

3. Patients with New-Onset LBBB:

• Associated with increased risk of PPM implantation (RR: 1.89) 1
• Permanent pacemaker may be considered (Class IIb recommendation) 1
• Continue transvenous pacing for at least 24 hours with continuous cardiac monitoring 1
• Approximately 50% will resolve at 6-12 months 1

4. Patients with Normal Conduction Post-Procedure:

• Risk of delayed AV block is <1% 1
• Temporary pacemaker can be removed immediately post-procedure
• Continue cardiac monitoring for 24 hours and repeat ECG the following day 1

Interventions and Monitoring Strategies

Immediate Post-Procedure:

• Rapid atrial pacing test (up to 120 bpm) to predict need for permanent pacing:
  • If Wenckebach AV block does not develop: Low risk (1.3%) of needing PPM
  • If Wenckebach AV block develops: Higher risk (13.1%) of needing PPM 1, 2

Temporary Pacing Options:

• Permanent-temporary pacemaker (PTPM): Active-fixation lead with external pulse generator for patients with conduction abnormalities not meeting conventional PPM criteria 3
  • Allows time for assessment and may prevent unnecessary PPM implantation
  • Average duration of PTPM use: 2.3 days 3

Monitoring Duration:

• High-risk patients (pre-existing RBBB, new LBBB): Minimum 24 hours of continuous cardiac monitoring 1, 2
• Delayed high-grade AV block risk exists for up to 7 days, with higher risk for self-expanding valves 1
• For patients with new conduction disturbances: Consider inpatient monitoring for at least 2 days and ambulatory monitoring for 14+ days post-discharge 2

Important Considerations and Pitfalls

Recovery of Conduction:

• Recovery rates: 22-68% of patients receiving PPM may recover conduction within 10-30 days 4, 5
• Low pacing requirements: 27% of patients with PPM had <1% ventricular pacing requirements during follow-up 3

Long-term Outcomes:

• PPM implantation within 30 days post-valve replacement is associated with higher mortality and heart failure hospitalization during follow-up (HR 1.11) 6
• Consider this risk when making decisions about PPM implantation in borderline cases

Specific to TMVR:

• While most evidence focuses on TAVR, similar principles apply to TMVR patients 7
• Monitor for conduction disturbances after TMVR as they can also lead to high-grade AV block requiring pacemaker implantation

Practical Implementation

1. Assess baseline risk: Identify pre-existing conduction abnormalities (especially RBBB)
2. Monitor post-procedure: Continuous cardiac monitoring with appropriate duration based on risk
3. Perform daily ECGs: Track changes in PR and QRS intervals
4. Consider atrial pacing test: To predict need for permanent pacing
5. Implant PPM before discharge: For persistent high-grade AV block or recurrent episodes of transient high-grade AV block

Do not discharge high-risk patients (especially those with new LBBB or pre-existing RBBB) without adequate monitoring plans, as delayed high-grade AV block can occur with potentially fatal consequences. 1, 2