[1] UNIV HELSINKI, DEPT MED, SF-00170 HELSINKI 17, FINLAND
[2] HAMMERSMITH HOSP, ROYAL POSTGRAD MED SCH, CARDIOVASC RES UNIT, LONDON W12 0HS, ENGLAND
[3] HARVARD UNIV, BRIGHAM & WOMENS HOSP,SCH MED,DEPT MED, DIV CARDIVASC, BOSTON, MA 02115 USA
[4] GEN PRACTITIONER RES GRP, TWICKENHAM, ENGLAND
[5] UNIV OXFORD, DEPT PSYCHIAT, OXFORD, ENGLAND