We can now see that the development of the coronary care unit, which Braunwald  has called ‘the single most important advance in the treatment of AMI’, was inevitable. But this was not obvious to most cardiologists of the day because so few of them considered the management of myocardial infarction to be a primary concern. They saw the diagnosis and treatment of congenital and rheumatic heart disease to be their main function. In 1956, when I was training under Paul Wood at the National Heart Hospital, I was advised by a Professor of Medicine in London not to become a cardiologist because ‘all the mitrals had been operated on’.
Insofar as there was an interest in myocardial infarction, this was concentrated on two modes of treatment — anticoagulants and inotropic drugs. Irving Wright of New York wrote a 1000-page book on myocardial infarction, mentioning cardiac arrest and ventricular fibrillation in a footnote only . The main concern of the book was the use of anticoagulant drugs. There was also a lively interest in the use of noradrenaline in shock; it was claimed that this drug reduced the mortality of this complication from 80 to 50%.
There were, however, other developments taking place in the 1950s that led to the explosion of interest in coronary disease that took place in the 1960s. Beck had pioneered open-chest defibrillation and reported the successful resuscitation of a physician with myocardial infarction in 1953 . He wrote, with remarkable foresight, ‘This one experience indicates that resuscitation from a fatal heart attack is not impossible and might be applied to those who die in hospital and perhaps to those who die outside hospital’. A few more cases were described in the succeeding years and it became fashionable for the more enthusiastic surgeons to carry a scalpel in their wallet. Richard Ross of Baltimore has described how he awoke from a faint to see a surgical colleague with a scalpel poised over his chest.
Zoll in Boston introduced external defibrillation in 1956 , and, shortly afterwards, Kouwenhoven et al. at Johns Hopkins  showed the effectiveness of combining mouth-to-mouth breathing, sternal compression and closed chest electrical defibrillation in restoring normal cardiac function in victims of ventricular fibrillation. It was this advance that triggered the interest in intensive care for myocardial infarction.
It is, perhaps, worth mentioning here that these techniques, in embryo, were in use in the late 17th century. In 1809, Allan Burns in his classic work ‘Observations on Diseases of the Heart’ had written in the chapter entitled ‘On disease of the coronary arteries and on syncope anginosa’ — ‘where, however, the cessation of vital action is very complete, and continues long, we ought to inflate the lungs, and pass electric shocks through the chest’.
My own interest in coronary disease may have been stimulated by my father having sustained a nonfatal infarction in 1954. Another factor was being Samuel Levine Fellow of Cardiology at what was then the Peter Bent Brigham Hospital in 1957–1958. Dr. Levine, who had introduced the armchair treatment of myocardial infarction some years earlier, was still an active member of the staff. During the same year, I learned of Zoll's work and saw a demonstration at the Massachusetts General Hospital of an electrocardiographic machine that was triggered by the onset of an arrhythmia. Returning to the United Kingdom with a position at the Royal Infirmary, Edinburgh, I and a colleague (David Leak) were impressed by a film made by Russell Brock on treating cardiac arrest by an open chest technique. We decided that, if a suitable occasion arose, we would treat a cardiac arrest in this way. On May 5, 1960, while poised with a scalpel in my hand, about to do a venous cutdown as a preliminary to a cardiac catheterisation, David Leak came into the laboratory and told me that a physician with a myocardial infarction had been admitted into an adjacent ward and had sustained a cardiac arrest. I had little choice but to go ahead with our plan, so I opened his chest and started cardiac massage. Cardiac surgical colleagues arrived with a defibrillator shortly afterwards, and we were able to resuscitate the patient. He made an excellent cardiac but rather a slow mental recovery, suffering particularly from verbal aphasia — there was a period when he could say ‘surgeon’ but not, for some unexplained reason, ‘physician’. He survived for 23 years in good health after this event, with slight impairment of cerebral function.
By a remarkable coincidence, our resuscitated physician was an alumnus of Johns Hopkins and, shortly after his recovery, he showed me a note in the hospital bulletin about Kouwenhoven's work. By this time, we had already attempted two other open chest resuscitations; in both cases, sinus rhythm had been restored but death ensued, probably because of the delay in initiating treatment. In the succeeding months, we treated another two patients with the Kouwenhoven technique, being initially successful but both died some days later.
It became very clear that the potential of cardiopulmonary resuscitation (CPR) was great but could not be realised because of the inherent delays when patients with myocardial infarction were scattered throughout the hospital, when there were very few trained in the techniques of CPR, and when there was a dearth of appropriate apparatus.
This experience led me to write in 1961  ‘Many cases of cardiac arrest associated with acute myocardial ischaemia could be treated successfully if all medical, nursing and auxiliary staff were trained in closed chest cardiac massage and if the cardiac rhythm of patients with acute myocardial infarction were monitored by an electrocardiogram linked to an alarm system’… ‘All wards admitting patients with acute myocardial infarction should have a system capable of sounding an alarm at the onset of an important rhythm change and recording the rhythm automatically on an ECG’…and ‘The provision of the appropriate apparatus would not be prohibitively expensive if these patients were admitted to special intensive care units. Such units should be staffed by suitably experienced people throughout the 24 h’. The Lancet was initially unwilling to publish the details of the four patients that we had treated unsuccessfully, but agreed to publish them when it was pointed out these were more instructive than those of the successful case.
In August 1961, I emigrated to Sydney with the intention of putting these ideas into practice. Thanks to the strong support of Malcolm Whyte and Gaston Bauer, plans to provide the necessary beds, apparatus, and training were put in hand in October 1961, and we started monitoring patients with myocardial infarction in Sydney hospital early in 1962. Later in that year, the monitoring of all patients with heart attacks had become routine in the research ward of the hospital.
In the United States, Hughes Day of Kansas City is regarded as the pioneer of coronary care and it is he who coined the term ‘coronary care unit’ (CCU) . Soon after hearing about the work of Kouwenhoven, he introduced a mobile crash cart, equipped with defibrillator and external pacemaker, into the 200-bed private Bethany Hospital. Because patients with myocardial infarction were scattered around the hospital, the initial results were very poor. He concluded that patients at risk should be kept under surveillance in an environment suitable for immediate resuscitation and he opened a special unit for this purpose in May 1962. Surprisingly, he found asystole the commonest arrhythmic problem (eight out of 11 cardiac arrests).
Almost simultaneously, two other hospitals in North America were approaching the problem in different ways. Brown and MacMillan in Toronto General Hospital were primarily interested in recording arrhythmias in acute myocardial infarction, and had adapted an old electroencephalograph to register continuously the electrocardiograms of patients with this condition . Again, surprisingly, ventricular fibrillation was found to be relatively uncommon.
In the Presbyterian University of Pennsylvania Medical Center, Meltzer and Kitchell opened a two-bed research unit in November 1962 . They later wrote ‘The results were dismal: the resident physicians were hopelessly bored with the inactivity and the seemingly endless vigil, and it became necessary to discontinue the effort abruptly to avoid (what now would be called) a demonstration. By default, a system of specialized care was then conceived wherein nurses rather than physicians assumed the primary responsibility for surveillance as well as for emergency treatment’. This group must take credit for establishing nurses as the key personnel of coronary care.
Our initial report from Sydney Hospital was submitted to the Lancet early in 1963, but it was rejected because the journal had recently accepted the report from Brown et al. in Toronto . The paper was rejected by the British Medical Journal because ‘it was irresponsible to suggest that all patients with myocardial infarction should be admitted to wards in which they could receive intensive care’. It was then submitted to the Medical Journal of Australia where it lay for some months until Graeme Sloman pointed out the importance of the subject and contributed an article on his similar experiences in Melbourne .
I returned to Edinburgh in 1964, and with Michael Oliver, planned a major unit in the Royal Infirmary. In 1967, we held the first international conference on coronary care, and most of the leading figures in the field attended.
In retrospect, it is interesting to note the topics that dominated discussion. The most charismatic personality was that of Bernard Lown who managed to convince most of the participants that our efforts should be concentrated on the detection and suppression of ventricular arrhythmias. If we were to do this, he told us, ventricular fibrillation would be a thing of the past. This advice was highly influential, and over the succeeding years, more and more sophistication in the recognition of arrhythmias was required of nurses. Indeed, a nurse being interviewed for a post in our unit was asked what her greatest personal weakness was. She replied ‘the inability to distinguish hemiblocks’.
Chazov of Moscow was also at the meeting and talked with enthusiasm of the use of fibrinolytic therapy and how this therapy leads ‘to rapid relief of pain, less cardiac failure, less rise of blood transaminase, and more rapid signs of ECG healing’ . Another trail blazer present was Pantridge of Belfast who had initiated mobile coronary care in that city in 1966 .
We now realise that the overemphasis on arrhythmia detection and treatment was a mistake, whereas the contributions of Chazov and Pantridge, which were received at the time with some scepticism, have been vindicated by the passage of time.
The concept of coronary care had been quickly adopted in the United States, but much more slowly in Europe. There was a remarkable degree of antagonism in some quarters, notably by the pioneer of ‘evidence-based medicine’ Archie Cochrane and the famous epidemiologist Geoffrey Rose. In 1972, Cochrane had written ‘the battle for coronary care is just beginning’  and Rose  particularly criticised the failure of CCUs to compare their experiences before and after their introduction. In fact, our unit in Edinburgh had done this , and we had written an article entitled ‘Problems in evaluating coronary care units’ . For some reason, Rose did not refer to our articles. We had pointed out the potential difficulties of carrying out randomised trials but two went ahead, one in Bristol and the South-West of England  and the other in Nottingham . No benefit of hospital treatment was established but in both studies low-risk patients were enrolled and the trials were not adequately powered to address the issues. Unfortunately, these negative findings influenced the Department of Health which failed conspicuously to support the development of coronary care units in England and Wales. It is of interest that, because the treatment of cardiac arrest does not lend itself to randomised trials, the spectacularly successful results of cardiopulmonary resuscitation are still not regarded as ‘evidence-based’ and do not figure in books such as ‘Evidence-based Cardiology’ .
Both Chazov and Pantridge had believed that prompt and appropriate treatment could limit the size of the eventual infarction. This concept of infarct size limitation was taken up vigorously by the Myocardial Infarction Research Units in the United States because it was realised that, now that arrhythmias could generally be prevented or controlled, the outstanding problem was pump failure. Over the succeeding years, large numbers of experiments in both animals and man were undertaken to establish the value of various strategies. Although animal experiments had often been promising with such agents as calcium antagonists and hyaluronidase, these did not translate into clinical practice. During this era, only beta-blockers were shown to be effective in reducing mortality in myocardial infarction and it is by no means certain that this was achieved by reducing infarct size.
The next major advance was the recognition of the value of fibrinolytic therapy, especially when combined with aspirin. Streptokinase was first introduced for the treatment of myocardial infarction by Sherry and his colleagues in the United States, but it was not widely applied in North America or the United Kingdom in the succeeding decades. Over the years, many trials of fibrinolytic therapy were carried out with variable results and it was not until the publication of the GISSI trial from Italy  and the international ISIS-2 trial  that this therapy became accepted as standard.
Many advances have subsequently been introduced into the management of myocardial infarction. These include angiotensin converting enzyme therapy and, perhaps most importantly, percutaneous coronary interventions. As a result, little further reduction in fatality can be anticipated in patients who are admitted to coronary care units. Yet, the mortality of acute heart attacks remains high — in the community, and in patients whose infarction is not promptly recognised. Attempts to improve the early diagnosis and care of patients with myocardial infarction have achieved only very limited success, mainly because symptoms in the elderly, who now comprise a high proportion of victims, are often difficult to assess.
The future of the coronary care unit will depend upon changing strategies of management and economic considerations. Bearing in mind the great cost of providing advanced forms of care, it is essential that, as far as possible, only patients who need intensive therapy are admitted to the most sophisticated units. Triage becomes of increasing importance; modern techniques of stratifying patients will permit the selection of the most appropriate and cost-effective mode of care for each individual.
The coronary care unit has come a long way in the 40 years of its existence. Although at one time it was anticipated that it would be gradually phased out, it seems probable that it will continue to provide a critically important component in the management of heart attacks.