Heart of the Matter

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The year 2017 marked the 50th anniversary of several important developments in medical care. In 1967, a classic study by Killup and Kimball was published regarding the care of patients admitted to New York Hospital for myocardial infarctions (heart attacks, or MIs). In the study, these patients were placed in a specialized hospital unit where they had constant monitoring of their heart rhythm. One of the greatest dangers following an MI is the sudden development of an abnormal heart rhythm, or a fatal arrhythmia. The authors of the study reported that this heart monitoring, along with staff trained to respond quickly to an arrhythmia, significantly reduced mortality from MIs. This was the birth of the coronary care unit, or CCU.

Prior to this study, patients admitted for MIs were placed in wards with other patients (hospitals years ago had some private rooms for the privileged few but most patients were admitted to large wards where there were 10 or 12 other patients in the same room). Patients with MIs were placed in the ward with an oxygen tent and mortality rates were 30 to 40 percent. Primitive monitors were sometimes used but were not watched constantly. After this study, the National Institute of Health (NIH) supported the Myocardial Infarction Research Unit, or MIRU. Under MIRU, CCUs were set up in multiple hospitals around the country. Many of the faculty and trainees in the MIRU program would go on to become leaders of academic cardiology for years to come. During the MIRU project, deaths from heart attacks dropped precipitously.

MIs are classified according to severity using the Killup classification system where Class I is a mild heart attack with no complications to Class IV is a major heart attack with shock, heart failure, and other complications. In the past 50 years, there have been many advances in the management of MIs including coronary artery bypass surgery, which also celebrated its 50th anniversary last year, coronary angioplasty and stents, intra-aortic balloon pumps, and left and right ventricular assist pumps (both devices are used to help a failing heart pump blood), anticoagulants, Beta-blockers, and hypothermia (cooling a patient with an MI). Thanks to these and other advances, the mortality for Killup Class III and IV patients has been reduced to under five percent and the mortality for Class I patients is negligible. Other advances outside of the hospital like pre-hospitalization coronary care by trained paramedics and automatic external defibrillators have also helped reduce mortality.

In recent years, patients admitted to CCUs have more critical illness and complications, and the care of these patients goes beyond the skill of a clinical cardiologist and often requires the care of cardiothoracic surgeons, intensive care specialists, and many other specialists. For this reason some experts are now saying it is time to move beyond the CCU and create a “cardiac intensive care unit,” or CICU.

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