RT Journal Article SR Electronic T1 Dr Walker reply JF British Heart Journal JO Heart FD BMJ Publishing Group Ltd and British Cardiovascular Society SP 112 OP 113 DO 10.1136/hrt.55.1.112-b VO 55 IS 1 A1 P R Walker YR 1986 UL http://heart.bmj.com/content/55/1/112.2.abstract AB