Evaluation of a New Cardiac Pacemaker

Inclusion Criteria: * Subject must have one of the following clinical indications: 1. Chronic atrial fibrillation with 2 or 3° AV or bifascicular bundle branch block (BBB block) ; or 2. 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 3. Sinus bradycardia with infrequent pauses or unexplained syncope with EP findings; and * Subject ≥18 years of age; * Subject has life expectancy of at least one year; * Subject is not enrolled in another clinical investigation; * Subject is willing to comply with clinical investigation procedures and agrees to return for all required follow-up visits, tests, and exams; * Subject has been informed of the nature of the study, agrees to its provisions and has provided written informed consent, approved by the EC; * If female, for 3 months post-operative, subject will actively practice a contraception method, or will practice abstinence, or is surgically sterilized, or is postmenopausal. Exclusion Criteria: * Pacemaker dependent; * Known pacemaker syndrome, have retrograde VA conduction or suffer a drop in arterial blood pressure with the onset of ventricular pacing; * Hypersensitivity to \< 1 mg of dexamethasone sodium phosphate; * Mechanical tricuspid valve prosthesis; * Pre-existing pulmonary arterial (PA) hypertension or significant physiologically-impairing lung disease; * Pre-existing pacing or defibrillation leads; * Current implantation of an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy (CRT); * Presence of implanted vena cava filter; * Presence of implanted leadless cardiac pacemaker; * Pregnant or breastfeeding.