“…The operative mortality in 361 cases reported in recent series (Lambert et al, 1971;Cheanvechai et al, 1973;Conti et al, 1973;Fischl et al, 1973;Scanlon et al, 1973;Segal et al, 1973;Bonchek et al, 1974;Berndt et al, 1975) was 9 4 per cent and the perioperative infarct rate 13 per cent. Of the 180 patients who survived surgery and who have been followed for more than 1 year (Conti et al, 1973;Fischl et al, 1973;Segal et al, 1973;Bonchek et al, 1974;Berndt et al, 1975), there has been a late mortality of only 1 per cent per year during a follow-up period of 16 months.…”