Micra Transcatheter Pacing Study

Inclusion Criteria: * Subjects who have a Class I or II indication for implantation of a single chamber ventricular pacemaker according to ACC/AHA/HRS 2008 guidelines and any national guidelines * Subjects who are able and willing to undergo the study requirements and are expected to be geographically stable for the duration of the follow-up. * Subjects who are at least 18 years of age (or older, if required by local law). Exclusion Criteria: * Subjects who are entirely pacemaker dependent (escape rhythm \<30 bpm). (Please note: Subjects who are entirely pacemaker dependent (escape rhythm \<30 bpm) can now be included in the study. Medtronic notified all sites on July 23, 2014 that the restriction against pacemaker dependent subjects was lifted, following review of the Early Performance Assessment.) * Subject has an existing or prior pacemaker, ICD or CRT device implant. * Subject has unstable angina pectoris or has had an acute myocardial infarction (AMI) in the 30 days prior to eligibility assessment. * Subjects with current implantation of neurostimulator or any other chronically implanted device which uses current in the body. Note that a temporary pacing wire is allowed. * Subjects with a mechanical tricuspid valve, implanted vena cava filter, or left ventricular assist device (LVAD). * Subjects who are morbidly obese and physician believes telemetry communication of ≤5 inches (12.7 cm) could not be obtained with programmer head. * Subjects whose femoral venous anatomy is unable to accommodate a 23 French introducer sheath or implant on the right side of the heart (for example, due to obstructions or severe tortuosity) in the opinion of the implanter. * Subjects who are considered as unable to tolerate an urgent sternotomy * Subjects with a known intolerance to Nickel-Titanium (Nitinol) Alloy. * Subjects for whom a single dose of 1.0mg dexamethasone acetate may be contraindicated. * Subjects with a life expectancy of less than 12- months. * Subjects who are currently enrolled or planning to participate in a potentially confounding drug or device trial during the course of this study. Coenrollment in concurrent trials is only allowed when document pre-approval is obtained from the Medtronic study manager. * Pregnant women, or women of child bearing potential and who are not on a reliable form of birth control. * Subjects with exclusion criteria required by local law (e.g. age, breast feeding, etc.).