How to manage bradycardia (abnormally slow heart rate) after Transcatheter Mitral Valve Replacement (TMVR) procedure?

Management of Bradycardia After TMVR Procedure

Symptomatic bradycardia after TMVR requires permanent pacemaker implantation before discharge to prevent potentially fatal outcomes. 1

Understanding Bradycardia After Transcatheter Valve Procedures

Bradycardia following transcatheter mitral valve replacement (TMVR) is a recognized complication similar to what occurs after transcatheter aortic valve replacement (TAVR), though with some important differences:

• While most evidence focuses on TAVR-related conduction disturbances, the principles apply to TMVR due to similar anatomical considerations
• The proximity of the mitral valve apparatus to the conduction system makes conduction disturbances a potential complication
• The risk of delayed high-degree atrioventricular block exists with both procedures

Assessment Algorithm

1. Immediate evaluation:

   • Document the type and severity of bradycardia
   • Compare with baseline ECG to identify new conduction abnormalities
   • Assess for symptoms (syncope, pre-syncope, fatigue, dizziness)

2. Risk stratification:

   • High risk: Symptomatic bradycardia of any type
   • High risk: New high-degree AV block or complete heart block
   • Moderate risk: New bundle branch block (especially RBBB)
   • Lower risk: Transient bradycardia that resolves completely

Management Recommendations

For Symptomatic Bradycardia:

• Permanent pacemaker implantation is indicated before discharge for patients with symptomatic bradycardia after TMVR 1
• Do not delay PPM implantation while waiting for spontaneous resolution as this puts the patient at unnecessary risk 2

For Asymptomatic Bradycardia:

• For high-degree AV block or complete heart block: Permanent pacemaker implantation is recommended before discharge 1
• For new bundle branch block: Extended monitoring is warranted with consideration for PPM if persistent 1

Temporary Management While Awaiting PPM:

• For symptomatic bradycardia requiring immediate intervention:
  • Atropine can be administered for temporary improvement in heart rate by blocking vagal effects on the AV node 3
  • Temporary pacing may be necessary if atropine is ineffective

Monitoring Recommendations

• All patients with new conduction disturbances should be monitored on telemetry with ability to perform emergency pacing if required 1
• For patients with new bundle branch block who don't receive a pacemaker, extended monitoring for at least 14 days is recommended 1
• The monitoring device should have the capacity to notify care teams quickly in the event of delayed high-degree AV block 1

Important Considerations

• Timing of PPM implantation: While specific timing hasn't been formally studied, the median time for pacemaker implantation after transcatheter valve procedures is approximately 3 days 1
• Risk of delayed events: In 29% of patients with new conduction abnormalities, the first episode of high-degree AV block occurs after discharge, with associated risk for syncope 1
• Mortality implications: Conduction disturbances after transcatheter valve procedures are associated with increased mortality risk, and early intervention is critical 2

Common Pitfalls to Avoid

• Underestimating risk in asymptomatic patients: Asymptomatic heart block can rapidly progress to symptomatic complete heart block 2
• Inadequate monitoring: Discharging with insufficient monitoring may not provide timely intervention if complete heart block develops 2
• Delayed intervention: Waiting too long for spontaneous resolution of conduction abnormalities increases risk of sudden cardiac death 1
• Failing to recognize high-risk features: Pre-existing conduction abnormalities significantly increase risk of requiring permanent pacing 1

By following this algorithm, clinicians can effectively manage bradycardia after TMVR procedures, minimizing the risk of adverse outcomes including sudden cardiac death.