RT Journal Article SR Electronic T1 Lower 24 hour urinary sodium concentrations are associated with more severe symptoms in subjects with vasovagal syncope JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 687 OP 688 DO 10.1136/hrt.2003.020115 VO 90 IS 6 A1 J L Hampton A1 S W Parry A1 R A Kenny A1 J L Newton YR 2004 UL http://heart.bmj.com/content/90/6/687.abstract AB