Chances are, you know someone who has survived a heart attack. The modern treatment of heart attacks has saved millions of lives worldwide. Dr Peter Rentrop, a pioneer in this field, reviews its beginnings.
In 1880, Dr Karl Weigert, Professor of Pathology in Leipzig, Germany, established the basis for our current treatment when he recognized that myocardial infarction is caused by abrupt cessation of blood flow due to a blood clot in one of the heart’s arteries (coronary thrombosis).
Dr James Herrick familiarized American physicians with this insight and with the clinical manifestations of heart attacks in his 1912 landmark paper “Clinical features of sudden obstruction of the coronary arteries”. He stressed that acute myocardial infarction is not inevitably fatal, as was widely believed. In 1918, he showed that changes in the electrical activity of the heart caused by myocardial infarction could be identified on the electrocardiogram and prove the diagnosis.
Herrick’s publications created an awareness of myocardial infarction among clinicians that hardly existed before. Treatment of patients with heart attacks was guided by Herrick’s statement in his 1912 paper: “If these cases are recognized, the importance of absolute rest in bed for several days is clear.” Physicians believed that death most frequently resulted from a tear in the infarcted heart muscle, called myocardial rupture, and that physical activity increased this risk. Bedrest remained the core treatment of acute myocardial infarction for almost half a century. It was soon extended to 3 weeks, followed by in-hospital ambulation for another three weeks. Support for this treatment came in 1939 from a study by Kenneth Mallory, who showed that replacement of infarcted heart muscle by a firm scar required up to two months.
Immobilization was, at times, extreme. Samuel Levine, a physician practicing in Boston, recommended in 1929 that patients should not feed themselves nor lift themselves in bed in the early days after infarction. The liquid or soft solid diet fed to the patient by nurses did not require much chewing. Emotional rest was also considered essential. Visitors were not allowed. Extensive examinations were to be avoided. Morphine was administered liberally to control the intense pain often associated with acute myocardial infarction.
As physicians diagnosed and treated patients with heart attacks more frequently, they began to realize that rupture of the heart muscle was not the most frequent cause of death. Levine directed attention to dangerous irregularities of the heartbeat, arrhythmias caused by acute myocardial infarction, and introduced drug treatments for some of these conditions. Signs of weakness of the heart muscle were observed in patients with large infarcts. This complication, called heart failure, was treated with fluid restriction and the administration of digitalis. Severe heart failure was recognized as a frequent cause of death. The high mortality rate of myocardial infarction was not significantly decreased by the available treatment modalities.
In the late 1950s, however, important insights were gained, and technical breakthroughs occurred. Ventricular fibrillation, a severely abnormal heart rhythm, was recognized as the most frequent cause of death in patients with acute myocardial infarction. In ventricular fibrillation, the coordinated activity of the muscle fibers, which is organized by the electrical current displayed on the electrocardiogram, is lost. The muscle fibers contract in a chaotic fashion, the heart muscle quivers instead of pumping blood, and the patient dies suddenly.
Several investigators showed in experimental animals that an electrical shock administered directly to the heart could break this disorganization and restore normal electrical activity and contraction, a procedure called defibrillation. The surgeon Dr Claude Beck of Cleveland, Ohio performed the first defibrillation of an exposed human heart in 1947 as an unplanned emergency procedure, when a 14-year-old patient experienced ventricular fibrillation during surgery. Beck developed the procedure further and it became rapidly standard in operating rooms.
Open-chest defibrillation was obviously not suitable for the treatment of heart attack patients in general wards. In 1956, Paul Zoll, a Boston cardiologist, introduced an apparatus that delivered the required electrical shock to the heart through the unopened chest, known as external cardiac defibrillator, rendering this treatment available outside of operating rooms.
A second breakthrough was the development of the modern cardiopulmonary resuscitation technique (CPR), the combination of closed-chest, cardiac massage with mouth-to-mouth respiration, which William Kouwenhoven published in 1960.
Two physicians understood that infarct patients with a high risk of ventricular fibrillation could not benefit adequately from these new procedures because of the hospital policies of that time. Patients with heart attacks were placed into the calmest available reas on the ward, usually far away from the nurses’ station with its hustle and bustle, often to be found dead in bed at routine rounds. Dr Morris Wilburne in California and Dr Desmond Julian in England suggested the solution in October of 1961, when they published almost simultaneously the concept of the Coronary Care Unit.
Both physicians envisioned placing all patients with acute myocardial infarction in specialized intensive care units staffed and equipped to discover and treat potentially fatal arrhythmia without any time delay. There would be 24-hour coverage by nurses trained to recognize ventricular fibrillation and ventricular standstill, a second potentially fatal arrhythmia. The patient’s electrocardiogram would be continuously displayed, and an audible alarm would be triggered by the occurrence of ventricular fibrillation or ventricular standstill. A defibrillator and an external pacemaker to treat ventricular standstill, as well as drugs to support the resuscitative effort, would be available in the unit. The nursing staff would be qualified to administer cardiopulmonary resuscitation combined with defibrillation or external electrical pacing of the heart.
Neither Dr Wilburne nor Dr Julian were afforded the opportunity to pioneer the implementation of their vision. This was left to Dr Hughes Day, who opened the first coronary care unit in Kansas City in 1962. Cardiologists rapidly embraced the concept across the industrialized world, and coronary care units were established in all major hospitals within five years. Rapid recognition and treatment of potentially fatal arrhythmias in these units reduced the in-hospital mortality of myocardial infarction from approximately 30% to 15%, a dramatic improvement. Dr Klaus Peter Rentrop felt very privileged in 1967 when he was chosen to serve as the first intern in the coronary care unit of the University Hospital in Giessen, Germany, and still remembers the staff’s and his own excitement on opening day; they knew they were entering a new era. However, patients were still at high risk. Death now occurred primarily among patients with large infarcts due to severely weakened pump function of the heart.
This outcome would be prevented only if the size of the heart attack could be limited. Herrick hinted at such a therapy when he speculated in his 1912 paper about an improvement of blood supply as “the hope for the damaged myocardium.” The path to the realization of this hope took unexpected twists and turns. It will be the subject of another review by Dr Peter Rentrop MD.
