Brief Summary: This cohort study aims to compare thoracoscopic left atrial appendage excision plus atrial fibrillation ablation versus oral anticoagulants for secondary prevention of stroke and non-central nervous systemic embolism in patients with atrial fibrillation and thromboembolism.

Detailed Description: BACKGROUND: Atrial fibrillation (AF) is one of the most common cardiac arrhythmias and has been shown to be an important cause of stroke. AF is responsible for 15% of all strokes. Most strokes in AF are caused by cardioembolism. The left atrial appendage (LAA) is the dominant source of cardioembolism. The greatest priority in treating AF is stroke prevention. There are now 3 main approaches for prevention: (1) oral anticoagulation (OAC), (2) eradication of AF, and (3) exclusion of the LAA from the systemic circulation. OAC therapy, including warfarin and novel oral anticoagulants, effectively reduces the risk of stroke in AF and is currently the first line of treatment in patients with AF and one or more risk factors. Despite the advancements in medical therapy, the risk of stroke in patients with AF who undergo optimal anticoagulation therapy still remains between 2% and 5% per year, regardless of the agent used. The limitations of OAC include (1) patient unsuitability for OAC, (2) increased risk of bleeding, (3) need for monitoring optimal international normalized ratio (INR) levels (with warfarin), and (4) patient noncompliance. Percutaneous methods of ablation are widely used to attempt to eliminate AF. Approximately 20% of patients who underwent ablation had AF recurrence. It is because of this well-demonstrated occurrence that the guidelines do not recommend discontinuation of warfarin or equivalent therapies after ablation. Since at least 90% of all left atrial thrombi are found within the LAA, it is plausible that its occlusion will lead to a decreased risk of stroke in patients with AF. However, the evidence for surgical excision is extremely limited.

AIM OF THE STUDY: The primary objective of this study is to evaluate whether thoracoscopic LAA excision plus atrial fibrillation ablation for the purpose of prevention of thromboembolism in patients with AF and thromboembolism is more effective and safer compared with OACs for reducing the composite endpoint of stroke, TIA and systemic embolism. The primary end point was the composite of ischemic stroke/systemic embolism/transient ischemic attack (TIA), major bleeding, or all-cause mortality. The secondary end point is defined as ischemic strokes, all strokes (including ischemic and hemorrhagic), major and fatal bleeding events, minor bleeding complication, all-cause mortality, cardiovascular death, and hospitalization due to cardiovascular or cerebral diseases.

STUDY DESIGN: This is a single-center prospective cohort study. Adult patients with non-valvular AF and a previous history of ischemic stroke/systemic embolism/ TIA are eligible for inclusion of this study. Approximately 300 patients with paroxysmal or persistent AF and previous thromboembolic events will receive novel oral anticoagulant or warfarin treatment with a targeted INR between 2.0 and 3.0 or surgical LAA excision plus AF ablation. Follow-up for these patients includes visits at 3 m, 6 m, 9 m, 12 m, and every additional 6 months there after.