Chronic Evaluation of Novel Pacemaker System

Inclusion Criteria:

1. Age 18 or above

2. Willing and capable of providing informed consent

3. Class I or IIa indication for implantation of a single-chamber ventricularpacemaker, according to ACC/AHA/HRS guidelines

4. A life expectancy of at least one year, and is a suitable candidate based on overallhealth and well-being

Exclusion Criteria:

1. Patients with complete AV block or other pacemaker-dependent conditions

2. Patients in whom a substernal device implant should be avoided:

3. Any prior sternotomy;

4. Any prior medical condition or procedure that leads to adhesions in theanterior mediastinal space;

5. Any marked sternal abnormality, such as pectus excavatum or pectus carinatum

6. Prior abdominal surgery in the epigastric region

7. Planned sternotomy

8. Prior or planned chest radiotherapy

9. Hiatal hernia that distorts mediastinal anatomy

10. Adhesions in the anterior mediastinal space

11. Severe obesity so that subxiphoid/substernal tunneling cannot be safelyperformed

12. Patients with severe RV dilation, gross hepatosplenomegaly, or severe obesity suchthat subxiphoidal/substernal tunneling cannot be safely performed

13. Patients with a class III indication for a permanent pacemaker

14. Patients with decompensated heart failure not due to bradycardia and expected toworsen with chronic RV pacing

15. Patients with an implanted cardiac pacemaker, cardioverter defibrillator, cardiacresynchronization device, or neurostimulator device, or planned implantation of acardioverter defibrillator, cardiac resynchronization device, or neurostimulatordevice

16. Patients with a current or planned implantation of a substernal device, or anyimplanted device that would interfere with the implantation or operation of asubsternal device

17. Patients who have previously undergone an open-heart surgical procedure.

18. Patients with an active infection

19. Patient on chronic oral anticoagulation which cannot be temporarily discontinued forsurgery

20. Patients with a condition in which pericardial pacing would be difficult orimpossible, such as acute pericarditis, chronic pericardial effusion or pericardialthickening or calcification, cardiac tamponade, or chronic restrictive pericarditis

21. Patients who have tested positive for the COVID-19 in the past 3 months, or arecurrently showing symptoms consistent with COVID-19

22. Women of childbearing potential who are or might be pregnant at the time of thestudy or breastfeeding

23. Subjects with a life expectancy of less than 12 months

24. Patients who are currently enrolled or planning to participate in any concurrentclinical study with an investigational therapy

25. Patients with decompensated heart failure expected to worsen with chronic RV pacing

26. Patients with COPD with oxygen dependence