Prospective, non-randomized, single-arm, international multicenter, clinical safety and effectiveness of a leadless pacemaker system in patients who are indicated for a VVIR pacemaker.

Following completion of enrollments in the IDE, patients will continue to be enrolled in the continued access phase of the study under the same protocol.

The purpose of this study is to evaluate the safety and effectiveness of the leadless pacemaker system in treating patients with a slow heart rate or irregular heartbeats. The Nanostim leadless pacemaker provides bradycardia pacing as a pulse generator with built-in battery and electrodes, for permanent implantation in the right ventricle. As a leadless pacemaker, it does not need a connector, pacing lead, or pulse generator pocket, but it has the same operating principles as a conventional pacemaker.

Inclusion Criteria:

1. Subject must have one of the clinical indications before device implant in adherence with Medicare, ACC/AHA/HRS/ESC single chamber pacing guidelines including:

   • Chronic and/or permanent atrial fibrillation with 2 or 3° AV or bifascicular bundle branch block (BBB block), including slow ventricular rates (with or without medication) associated with atrial fibrillation; or
   • Normal sinus rhythm with 2 or 3° AV or BBB block and a low level of physical activity or short expected lifespan (but at least one year); or
   • Sinus bradycardia with infrequent pauses or unexplained syncope with EP findings; and

2. Subject ≥18 years of age; and

3. Subject has life expectancy of at least one year; and

4. Subject is not enrolled in another clinical investigation; and

5. Subject is willing to comply with clinical investigation procedures and agrees to return for all required follow-up visits, tests, and exams; and

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

7. Subject is not pregnant and does not plan to get pregnant during the course of the study.

Exclusion Criteria:

1. Subject has pacemaker syndrome, has retrograde VA conduction or suffers a drop in arterial blood pressure with the onset of ventricular pacing; or
2. Subject is allergic or hypersensitive to <1 mg of dexamethasone sodium phosphate; or
3. Subject has a mechanical tricuspid valve prosthesis; or
4. Subject has a pre-existing endocardial pacing or defibrillation leads; or
5. Subject has current implantation of either conventional or subcutaneous implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT); or
6. Subject has an implanted vena cava filter; or
7. Subject has evidence of thrombosis in one of the veins used for access during the procedure; or
8. Subject has an implanted leadless cardiac pacemaker; or
9. Subject had recent cardiovascular or peripheral vascular surgery within 30 days of enrollment