Background
By the end of the first decade of the twentieth century the AV conduction system had been described. Drug therapy for Stokes-Adams disease was being investigated and the lethal nature of the condition had been recognized. But a few physicians sought other treatments for the "stopped heart."
Albert S. Hyman (1893-1972), a practitioner cardiologist in New York City, has for decades intrigued historians of electrical stimulation of the heart, because in the early 1930s he invented an artificial pacemaker. We have attempted to reconstruct Hyman’s ideas and purposes and describe the workings and limitations of the invention.
"Intracardial Therapy" in the 1920s
After his residency and a period of study in Europe, during which he was greatly influenced by British cardiologist James Mackenzie, Hyman set up a clinical practice in New York City. With financial support from a small foundation he authored three reports (1930, 1932, 1935) and several newspaper reports on management of the "stopped heart." He advocated treatment by "intracardial (his term) therapy". At first this consisted of injection into the right atrium of one of several stimulants, usually but not exclusively coupled with epinephrine. He soon decided that it was not the stimulant itself that occasionally restored heart rhythm, but the needle’s puncturing the heart wall and setting up an action current of injury. He explained that during the first seconds of standstill, the threshold of electrical conductivity in the heart was lowered and myocardial tissue temporarily became more irritable.
Hyman asserted that the "ectopic beats" (his term, apparently the first such use) induced by the needle "were sufficient to restore a sufficient volume output of the left ventricle to flood the coronary system, which in turn led to the restoration of normal sinus nodal activity." If the physician could react swiftly enough, a good chance existed of reviving the heart with a single thrust. Hyman reported in 1930 that he had revived a woman, aged 45, who suffered from mitral stenosis and had been pronounced dead by the intern on service. Seven minutes after her "death," Hyman percutaneously and transthoracically inserted a needle into the woman’s right atrium. This irritant elicited "a very rapid, irregular [atrial] rate." Within an hour, the patient began to regain consciousness and "after a rather stormy six hour period she became conscious and could speak to those around her." Eight days later, she died of her underlying heart disease. "No attempt was made to resuscitate her the second time."
Hyman recommended atrial injection as a means of restarting the heart stopped in its entirety with neither atrial nor ventricular function. In each of his three reports he described the "stopped heart" as the result of anoxemia (his term). Only in the third paper (1935) did Hyman mention the possibility of injecting the ventricles as well as the right atrium, though he still advocated atrial injection only. He recommended that "intra-auricular puncture should be attempted in every case of death occurring as the result of the asystolic heart," but he knew that this period of heightened myocardial irritability was temporary. "As the electrodynamic balance of the entire heart becomes more and more disturbed, a single prick of the needle may not be sufficiently powerful. . . . Two or even three or more needle thrusts may be required." Yet he was plainly uneasy about making multiple punctures and began to consider other ways to deliver repeated irritants to the heart.
