Donald Emslie-Smith was educated at Trinity College, Glenalmond. After graduation, he held House Physicians and Medical Registrar posts at Aberdeen Royal Infirmary and then Poole General Hospital, Dorset. He became Registrar in Cardiology to Professor (later Sir) Ian Hill at Dundee Royal Infirmary, followed by spells as Research Fellow, Baker Institute, Melbourne, Australia (where he developed his interest in the ECG of hypothermia), then Senior Registrar in Medicine and Tutor in General Medicine at the Royal Postgraduate Medical School and Hammersmith Hospital under Professor Sir John McMichael.
On his return north as Senior Lecturer in Medicine, University of St Andrews and Consultant Cardiologist, Dundee Royal Infirmary, he published internationally recognised outstanding contributions in the fields of accidental hypothermia of the elderly and the intracardiac electrocardiogram.
Between 1963 and 1967 he was an Assistant Editor of the Scottish Medical Journal. In 1964 he supervised one of the first British Heart Foundation allocations of one of the first Lown DC cardioverters in the UK for the elective reversal of cardiac dysrhythmias. He was Chairman of the British Cardiac Society in 1987 and served on the Executive Committee of the Association of Physicians of Great Britain and Ireland. In 1987 he was President and Orator of the Harveian Society of Edinburgh. In 2013 he was given a Lifetime Achievement Award by the Scottish Cardiac Society.
He will be remembered as a lucid clinical teacher of both undergraduate and postgraduates. When teaching undergraduates about low-pitched murmurs, he proudly attributed his auscultation skills to the large bell of his stethoscope, made for him by a plumber in Cairo during his time there just after the Second World War. He was a staunch proponent and supporter of measures to improve the education and the lot of junior medical staff.
He was a Serving Brother and later Officer of the Order of the Hospital of St John of Jerusalem. His other interests included fly fishing, ornithology, Scottish alpine flowers, Roman Scotland, Greek, Roman and Byzantine classics, medical history, the antiques of Scotland and medical heraldry.
Predeceased by his wife Judy in 2005, he is survived by his son Alastair (also a doctor), his daughter Sophie, and four grandchildren.