RT Journal Article SR Electronic T1 Failed Mitral Valvotomy JF Thorax JO Thorax FD BMJ Publishing Group Ltd and British Thoracic Society SP 320 OP 326 DO 10.1136/thx.14.4.320 VO 14 IS 4 A1 J. K. Ross YR 1959 UL http://thorax.bmj.com/content/14/4/320.abstract AB