RT Journal Article SR Electronic T1 Left ventricular ejection fraction: are the revised cut-off points for defining systolic dysfunction sufficiently evidence based? JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 426 OP 428 DO 10.1136/hrt.2007.123877 VO 94 IS 4 A1 G Mahadevan A1 R C Davis A1 M P Frenneaux A1 F D R Hobbs A1 G Y H Lip A1 J E Sanderson A1 M K Davies YR 2008 UL http://heart.bmj.com/content/94/4/426.abstract AB