Asymptomatic Atrial Fibrillation and Stroke Evaluation in Pacemaker Patients and the Atrial Fibrillation Reduction Atrial Pacing Trial

Inclusion Criteria 1. Age ≥ 65 years 2. History of hypertension requiring pharmacological therapy (≥ 4 weeks of therapy). 3. Recent (\< 8 weeks) St. Jude Medical Inc. pacemaker implant (IDENTITY® Adx DR (Model 5386/5380)), ICD implant (EPIC 2 or Atlas 2) or other St. Jude Medical Inc. pacemaker or ICD with the same capabilities. 4. In pacemaker patients only the primary indication for pacing is sinus or AV node disease. Exclusion Criteria 1. Previous documented AF, atrial flutter (lasting greater than 5 minutes), or other sustained SVT (not including episodes detected by the device) 2. Geographic/social or psychiatric factor likely to interfere with follow-up 3. Requirement for oral anticoagulation (heart valve, deep vein thrombosis, etc.)