But he revealed in a television interview shortly before his death that his health was still improving after his first 'massive' attack in October, 1988.
He said it had been a 'rude awakening . . . a hell of a shock' for him but that it had opened as well as closed doors in his life. 'I took up mountaineering which has been one of the great joys of my life. I would never have got into mountaineering unless I had had this attack,' he said.
It is the commonest single cause of death in Britain. Every year at least 250,000 suffer a heart attack, or myocardial infarction, and 160,000 of them die.
When Mr Smith had his first attack, on a Sunday evening following the Labour Party conference, he was fortunate enough to already be in hospital. At home in Edinburgh, he had been planning to go to the opera when he began to feel unwell - 'uneasy, headachey, almost as if I was going out of my skin'.
His wife called in a GP friend who sent him to Edinburgh Royal Infirmary. Tests could find no evidence of anything wrong with his heart - so-called silent infarcts are not unusual. But when he was dressing to leave and bent down to tie his shoelaces, the attack struck suddenly and with force. He said afterwards he had 'dived into a black void'. The next he knew he was on a hospital trolley. He spent two days in the coronary care unit and another eight in a general ward.
A month later, having started to lose weight, he returned for a check-up. He told one interviewer that after a strenuous work-out on a treadmill, doctors had said his heart performed well. The next day he climbed a hill near his home: 'I broke the psychological barrier, you have to get your confidence.'
A heart attack happens when heart muscle is deprived of oxygen, usually because a clot, or thrombus, is blocking a blood vessel that feeds the heart. If severe enough, this results in heart failure when the ability of the heart to pump effectively is interrupted. The heart goes out of rhythm and arrythmias, abnormal heart beats, are common. The attack proves fatal, very often, because the patient suffers ventricular fibrillation which so severely interferes with the muscle cells that the heart stops pumping.