This year, 2017, marks the 50th anniversary commemorating the publication of an article describing the results from the classic study by Killip and Kimball showing a reduction in mortality from acute myocardial infarction in patients sequestered in a specialized hospital unit1 at New York Hospital in New York City. Also described in the article was the Killip Classification of acute myocardial infarction, which described and detailed the relationship between the presence or absence of classic heart failure and shock with mortality outcomes, a bedside prognostic index that has stood the test of time.
When we (WHF and JSA) were medical students in Boston during the mid-1960s, patients with acute myocardial infarction were placed in oxygen tents, often on large medicine wards mixed with other medical patients. The in-hospital mortality rate of patients ranged from 30% to 40%. One of us (WHF) remembers the case of a 35-year-old Boston fireman with an acute myocardial infarction who was admitted to the Pavilion Medical Service at Boston City Hospital onto a 40 patient bed male medicine ward, where he was put in an oxygen tent for 1 week, with his bed situated between that of a patient with terminal uremia and another dying of metastatic esophageal cancer. A primitive bedside arrhythmia monitor was used, and the constant beeping sounds kept all the other patients on the ward awake. The fireman survived the acute myocardial infarction on coumadin without having the common complication of acute pulmonary embolism from prolonged bedrest, the practice at the time.
With advances taking place during the 1960s in cardiac resuscitation procedures, such as the introduction of closed chest cardiac massage,2 transthoracic defibrillation,3 and cardiac pacemakers, the natural history of in-patient acute myocardial infarction began to change in a favorable direction. More effective arrhythmia monitoring technologies also became available.3
The concept of the coronary care unit (CCU) actually began in the early 1960s and was first conceived by Day4 in the United States, by Brown in Canada,5 and by Julian6 in the United Kingdom. The large New York Hospital experience reported in 19671 demonstrated that monitored patients in a CCU, especially those patients without pulmonary embolism or shock, seemed to benefit from being in such a monitored unit compared with those patients treated on a general medicine ward. The benefit related to the early recognition and treatment of arrhythmias. The New York Hospital experience also recognized that trained nurses could begin resuscitation efforts immediately while in-house physicians were being called.
Realizing the potential importance of the CCU, the National Institutes of Health supported the Myocardial Infarction Research Unit (MIRU) program to further improve outcomes with acute myocardial infarction. The MIRUs were located at the University of Alabama in Birmingham, Duke University in North Carolina, New York Hospital-Cornell in New York City (where WHF was a fellow and where TK was Chief of Cardiology), Cedars of Sinai Hospital in Los Angeles, the University of Rochester, the University of Chicago, Johns Hopkins, and Massachusetts General Hospital in Boston. Many of the participating faculty and trainees in the MIRU program would become the leaders of academic cardiology for years to come. The Swan-Ganz catheter came out of the MIRU program,7 adding hemodynamic monitoring to the role of the CCU.8
With other advances in the management of acute myocardial infarction,9 such as coronary artery bypass surgery (also celebrating its 50th year),10 coronary angioplasty and stenting, the intra-aortic balloon pump,11 left and right ventricular assist devices, extracorporeal membrane oxygenation,12 anticoagulants, β-adrenergic blockers,13 and hypothermia, the overall in-hospital mortality from myocardial infarction has been reduced below 5%, including Killip Class III and IV patients. For class I patients, the in-hospital mortality has become negligible. Advances have also taken place in prehospitalization coronary care by trained paramedics, and prevention of acute myocardial infarction has become a major emphasis of medical care and public policy compared with 50 years ago.
Of significance, in recent years the types of patients admitted to the CCU have changed. The patients who are now admitted have more critical illnesses and comorbidities. In a recent retrospective review of 1042 patients admitted to a CCU,14 the patient diagnoses continue to include patients with acute coronary syndromes (ST and non-ST elevation acute myocardial infarctions) but also those with severe heart failure (ischemic and nonischemic), valve disease, pericardial disease, primary ventricular and bradyarrhythmias, acute aortic dissection, renal failure, and sepsis. The care needs of these patients go beyond the expertise of the clinical cardiologist15 and require the input of cardiothoracic surgeons, cardiac electro-physiologists, heart failure specialists, pulmonary–critical care intensivists with expertise in ventilation, nephrologists, and infectious disease consultants. The term CCU should be changed to “cardiac intensive care unit” (CICU), reflecting the changing population and their care needs.
The 50th anniversary of the Killip-Kimball article marks an important milestone, and to quote the authors, “the development of the CCU represents one of the most significant advances in the hospital practice of medicine.”1
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-William H. Frishman, MD, Joseph S. Alpert, MD, Thomas Killip III, MD
This article originally appeared in the September 2017 issue of The American Journal of Medicine.
