PT - JOURNAL ARTICLE ED - , TI - British Cardiac Society AID - 10.1136/hrt.37.7.779 DP - 1975 Jul 01 TA - British Heart Journal PG - 779--784 VI - 37 IP - 7 4099 - http://heart.bmj.com/content/37/7/779.short 4100 - http://heart.bmj.com/content/37/7/779.full SO - Heart1975 Jul 01; 37