Introduction

The appropriateness of implanting a ventricular rate (VR) leadless pacemaker is determined by a combination of patient-specific factors, including life expectancy, infection risk, presence of prosthetic valves, left ventricular ejection fraction (LVEF), and patient mobility. These factors collectively influence the risk-benefit analysis for each patient. Understanding how they interact helps clinicians make informed decisions to optimize patient outcomes.

Life Expectancy

• Impact on Device Choice:

  • Long-Term Benefits: Patients with a longer life expectancy stand to benefit more from the reduced long-term complications associated with leadless pacemakers, such as the elimination of lead-related issues (e.g., fractures, insulation failures).

  • Device Longevity Considerations: Leadless pacemakers have a finite battery life (approximately 8–12 years). For patients with a long life expectancy, the potential need for future device replacements or extractions must be considered.

• Appropriateness Determination:

  • Younger Patients: May require multiple device replacements over their lifetime, and the current limitations in extracting leadless devices could pose challenges.

  • Elderly Patients or Those with Limited Life Expectancy: May benefit from the minimally invasive nature and reduced immediate procedural risks.

Infection Risk

• Impact on Device Choice:

  • Reduced Infection Rates: Leadless pacemakers eliminate the need for transvenous leads and subcutaneous pockets, which are common sources of infection in traditional pacemakers.

  • High-Risk Populations: Patients with prior device infections, immunosuppression, or comorbidities like diabetes are at increased risk for infections.

• Appropriateness Determination:

  • Patients with High Infection Risk: Leadless pacemakers are more appropriate due to their lower infection profile.

  • Infection Prophylaxis: Leadless systems are advantageous in patients where infection control is paramount.

Presence of Prosthetic Valves

• Impact on Device Choice:

  • Anatomical Considerations: The presence of prosthetic tricuspid valves can interfere with the implantation and function of leadless pacemakers.

  • Risk of Device-Valve Interaction: Potential for device dislodgment or interference with valve function.

• Appropriateness Determination:

  • Patients with Mechanical Tricuspid Valves: Generally considered inappropriate candidates for leadless pacemakers due to the risk of mechanical interference.

  • Patients with Bioprosthetic Valves: May be considered on a case-by-case basis, with careful imaging and assessment.

Left Ventricular Ejection Fraction (LVEF)

• Impact on Device Choice:

  • Risk of Pacing-Induced Cardiomyopathy: Chronic right ventricular pacing can worsen heart failure in patients with reduced LVEF due to dyssynchronous ventricular contraction.

  • Need for Cardiac Resynchronization Therapy (CRT): Patients with low LVEF may benefit more from CRT devices, which are not available in leadless forms.

• Appropriateness Determination:

  • Normal LVEF: Patients with normal or mildly reduced LVEF are appropriate candidates for VR leadless pacemakers.

  • Significantly Reduced LVEF: Leadless pacemakers are generally inappropriate, and devices capable of providing CRT should be considered.

Patient Mobility

• Impact on Device Choice:

  • Lifestyle Considerations: Active patients may have higher risks of lead dislodgement or pocket complications with transvenous systems.

  • Impact of Subcutaneous Pocket: Traditional pacemakers require a pocket that can be uncomfortable or restrictive for physically active individuals.

• Appropriateness Determination:

  • Highly Active Patients: Leadless pacemakers are appropriate as they eliminate the subcutaneous pocket and leads, reducing restrictions on movement and potential discomfort.

  • Limited Mobility Patients: May not derive significant additional benefit from a leadless system over a traditional pacemaker.

Collective Determination of Appropriateness

When these factors are considered together, they guide the clinician in determining the most suitable pacing strategy:

1. Optimal Candidates for Leadless Pacemakers:

   • Patients with normal LVEF, high infection risk, no prosthetic tricuspid valves, reasonable life expectancy, and high mobility are ideal candidates.

   • Example: An elderly patient with a history of device infections and normal cardiac function.

2. Suboptimal Candidates:

   • Patients with significantly reduced LVEF who require CRT, those with mechanical prosthetic tricuspid valves, or those with a very long life expectancy that exceeds the device's battery life without feasible extraction options.

   • Example: A young patient with heart failure and an LVEF of 30% needing biventricular pacing.

3. Individualized Assessment:

   • Risk-Benefit Analysis: Each patient's unique combination of factors must be evaluated to determine if the benefits of a leadless pacemaker outweigh the risks.

   • Patient Preferences: Consideration of the patient's lifestyle, values, and preferences is essential.

Conclusion

The collective consideration of life expectancy, infection risk, presence of prosthetic valves, LVEF, and patient mobility is crucial in determining the appropriateness of VR leadless pacemaker implantation:

• Life Expectancy: Balances the benefits of reduced complications against the challenges of device longevity and potential future replacements.

• Infection Risk: Prioritizes leadless systems for those at high risk to minimize infection-related morbidity.

• Prosthetic Valves: Avoids implantation in patients where device-valve interactions could pose significant risks.

• LVEF: Ensures that patients who would not benefit from single-chamber ventricular pacing are directed toward more suitable therapies.

• Patient Mobility: Enhances quality of life for active patients by reducing physical limitations associated with traditional devices.

By integrating these factors, clinicians can make evidence-based decisions tailored to individual patient needs, optimizing outcomes and resource utilization.

References

1. Reddy, V. Y., Exner, D. V., Cantillon, D. J., et al. (2015). Percutaneous Implantation of an Entirely Intracardiac Leadless Pacemaker. New England Journal of Medicine, 373(12), 1125–1135.

2. Duray, G. Z., Ritter, P., El-Chami, M., et al. (2018). Long-term performance of a transcatheter pacing system: 24-Month results from the Micra Transcatheter Pacing Study. Heart Rhythm, 15(5), 702–709.

3. Glikson, M., Nielsen, J. C., Kronborg, M. B., et al. (2021). 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. European Heart Journal, 42(35), 3427–3520.

4. Slotwiner, D., Varma, N., Akar, J. G., et al. (2019). HRS Expert Consensus Statement on remote interrogation and monitoring for cardiovascular implantable electronic devices. Heart Rhythm, 12(7), e69–e100.

5. Burke, M. C., Gold, M. R., Knight, B. P., et al. (2015). Safety and Efficacy of the Totally Subcutaneous Implantable Defibrillator: 2-Year Results From a Pivotal International Trial. Journal of the American College of Cardiology, 65(16), 1605–1615.

Note to Readers

This explanation is based on current evidence and expert consensus as of the latest guidelines. Individual patient circumstances may vary, and clinical judgment should always be applied. Future studies may provide additional insights that could refine these recommendations.