Evolution of the Coronary Care Unit: Past, Present, and Future

Early Days of Resuscitation

The first impactful therapy to attenuate the most common and life-threatening complications of MI, ventricular tachycardia and ventricular fibrillation, emerged with open-chest and, later, closed-chest defibrillation. Soon after these original descriptions, the overall construct of a CCU designed with specific goals to detect and treat fatal ventricular arrhythmias rapidly evolved.

Desmond Julian was the first to articulate the general construct of a CCU. In his original 1961 presentation to the Royal Thoracic Society, he described five cases of cardiac massage with the goal to resuscitate patients with acute MI. He came to the profound conclusion that “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 massage, and if the cardiac rhythm of patients…was monitored by an electrocardiographic link to an alarm system.” His vision for the CCU was founded on the following four basic principles:

• Continuous electrocardiogram monitoring with arrhythmia alarms

• Cardiopulmonary resuscitation with external defibrillator capabilities

• Admission of patients with acute MI to a single unit of the hospital where trained personnel, cardiac medications, and specialized equipment were readily available

• The ability of trained nurses to initiate resuscitation attempts in the absence of physicians

Approximately 3 years later, the first CCU was established at the Royal Infirmary of Edinburgh. Soon thereafter, several clinicians in North America developed specialized units devoted exclusively to the treatment of patients with suspected MI. Meltzer created a two-room research unit with an aperture in the wall through which defibrillator paddles could be passed from one patient to the other. Brown and associates established a four-bed unit with an adjacent nursing station and arrhythmia surveillance provided using a converted electroencephalogram unit with electrocardiogram amplifiers.

Day, a contemporary of Meltzer, Brown, and Julian, built mobile “crash carts” in an attempt to resuscitate patients with acute MI who were admitted to general medical wards. He recognized that delays in arrhythmia detection significantly limited the success of subsequent resuscitation attempts. As a result of his observations, an 11-bed unit was established at Bethany Hospital in New York staffed by “specially trained nurses who could provide expert bedside attention, interpret signs of impending decompensation and quickly institute CPR.” Day is largely credited with introducing the term code blue to describe resuscitation efforts for cyanotic patients following cardiac arrest and the term coronary care unit .

A Paradigm Shift—Prevention of Cardiac Arrest

Julian described the “second phase” of CCUs as an expansion from a sole focus on resuscitation to prevention of lethal arrhythmias and advanced care. Killip and Kimball published their experience of 250 patients with acute MI treated in a four-bed CCU at New York Hospital–Cornell Medical Center and reported that aggressive medical therapy reduced in-hospital mortality from 26% to 7%. This led Killip and Kimball to conclude that “the development of the coronary care unit represents one of the most significant advances in the hospital practice of medicine.” Not only did it seem that patients with acute MI had improved survival if treated in a CCU, but also all in-hospital cardiac arrest patients seemed more likely to survive if geographic­ally located in the CCU. “Although frequently sudden, and hence often ‘unexpected,’ the cessation of adequate circulatory function is usually preceded by warning signals.” Thus began the era of CCUs throughout the world, with a categorical focus on the prevention of cardiac arrest.

Lown and colleagues detailed the key components of the CCU at the Peter Bent Brigham Hospital in Boston. The foundation of their CCU centered on assembling a “vigilant group of nurses properly indoctrinated in electrocardiographic pattern recognition and qualified to intervene skillfully with a prerehearsed and well-disciplined repertoire of activities in the event of a cardiac arrest.” With a CCU mortality of 11.5% and an in-hospital mortality of 16.9%, these clinician-investigators hypothesized that an aggressive protocol for arrhythmia suppression after MI could virtually eradicate sudden, unexpected death. While cumulative data did not support routine preventive antiarrhythmic therapy in MI, the fundamental construct of advanced care for patients at risk for post-MI complications established a foundation for contemporary CCUs.

Additional developments in the care of patients with acute MI—including the use of intraaortic balloon counterpulsation, the implementation of flow-directed catheters for hemodynamic monitoring, and either pharmacologic or mechanical myocardial reperfusion therapy —contributed to the advance and wide-scale availability of CCUs.

Economic Impact of the Cardiac Intensive Care Unit

Intensive care units (ICUs) are places of high resource use and high expenditure. Accordingly, they contribute significantly to the economic burden of health care. While ICUs constitute less than 10% of hospital beds in the United States, estimates suggest that they consume more than 20% of total hospital costs and nearly 1% of the US gross domestic product. It has been reported that ICU costs have increased by nearly 200% in the years 1985 to 2000. These observations underscore the importance of patient selection and resource utilization. Contemporary data support similarities in resource use, morbidity and mortality, and in-hospital length of stay for ICUs and CICUs.