Percutaneous left atrial appendage closure for stroke prophylaxis in patients with atrial fibrillation: 2.3-year follow-up of the PROTECT AF (Watchman Left Atrial Appendage System for Embolic Protection in Patients with Atrial Fibrillation) trial - Reddy, V Y; Doshi, S K; Sievert, H; PROTECT AF Investigators (Circulation, 2013)