This is a prospective, randomized controlled (1:1) multicenter trial. The pilot study will be conducted up to three clinical sites in the United States. The primary purpose of this study is to compare the overall safety and efficacy between the leadless pacemaker and left bundle area pacing.

This is a prospective, randomized controlled (1:1) multicenter trial. The pilot study will be conducted up to three clinical sites in the United States. This study is designed to compare the safety and effectiveness of two types of pacemaker treatments: leadless pacemakers and left bundle area pacing. Patients who's heart rhythm indicate a degree of heart block that slows the heart beat and decreases the amount of blood the heart is pumping to the rest of the body will be identified by physicians to participate. This study seeks to improve our understanding of heart rhythm disorders to allow us to provide the best treatment for our patients.

Inclusion Criteria:

1. Age > 18

2. Planned for:

   1. permanent pacemaker implantation for AV node disease (first, second or third degree), OR
   2. post-TAVR patient requiring permanent pacemaker implantation

3. Preserved ejection fraction > 50%

4. Preserved sinus node function

5. Willingness to adhere to study restrictions and comply with all post-procedural follow-up requirements

6. Life expectancy > 1 year

7. Female subject of childbearing potential is not pregnant, not breast feeding, does not plan to be pregnant during the course of the study, and agrees to use a highly effective contraceptive method (i.e. IUD, birth control, vasectomized partner, sexual abstinence, etc.) during the course of the study.

8. Subject has been informed of the nature of the study, agrees to its provision and has provided written informed consent, approved by the IRB

Exclusion Criteria:

1. Sinus node dysfunction, anticipating atrial pacing or persistent atrial fibrillation

2. Anatomical restriction for either MICRA or transvenous pacing such as

   1. Access vein occlusion or thrombosis
   2. previous radiation therapy at insertion site
   3. inferior vena cava filter

3. Endstage renal disease (ESRD)/on dialysis

4. Dementia (inability to give consent)

5. Moderate to Severe or Severe Tricuspid valve regurgitation

6. Moderate to Severe or Severe Mitral valve regurgitation

7. History of mitral or tricuspid valve surgery

8. Preexisting implanted pacemaker or ICD or lead

9. Subject is allergic to titanium

10. Life expectancy < 1 year

11. Recurrent or high risk of infections

12. Active malignancy requiring systemic chemotherapy or local chest radiation

13. Subject has myocardial infarction, unstable angina, cerebrovascular accident, or heart failure admission within 3 months of the baseline visit

14. CABG, valve surgery or PCI within the last 3 months except TAVR

15. Other major cardiac surgery within the last 6 months

16. Persistent and permanent atrial fibrillation diagnosed by a healthcare provider

17. NYHA class 3 or 4 Heart Failure

    Additional post-TAVR Exclusion Criteria:

18. Evidence of renal injury (12 hours post-TAVR)

19. Access site complication(s) post-TAVR

20. Suspicion of stroke/cerebrovascular accident (CVA) or transient ischemic attack (TIA) within 12 hours post-TAVR

21. Physician suspicion that ambulation to pre-TAVR activities post-pacemaker implantation would be unattainable

22. Other post-TAVR complications that in the opinion of the investigator may seriously confound study outcomes

Clinical Events Committee is masked