RT Journal Article SR Electronic T1 Balloon valvuloplasty JF Heart JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 223 OP 228 DO 10.1136/heart.85.2.223 VO 85 IS 2 A1 Alec Vahanian YR 2001 UL http://heart.bmj.com/content/85/2/223.abstract AB