RT Journal Article SR Electronic T1 Alternatives to warfarin in atrial fibrillation: drugs and devices JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 1113 OP 1116 DO 10.1136/hrt.2007.118844 VO 94 IS 9 A1 Yves L Bayard A1 Stefan H Ostermayer A1 Horst Sievert YR 2008 UL http://heart.bmj.com/content/94/9/1113.abstract AB