title: Watching the watchman.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Block
mesh_terms: D020517:Atrial Appendage; D001281:Atrial Fibrillation / Q000150:complications*; D005240:Feasibility Studies; D006801:Humans; D019736:Prostheses and Implants; D020521:Stroke / Q000209:etiology* / Q000517:prevention & control*