Pacemaker

Cardiac electro-stimulation, which is the basic function of the pacemaker, began in the mid eighteenth century. This was an important part in why this was a turning point in world history because electrical currents play a huge role in pacing. Electrical currents were first used on animals to stimulate cardiac nerves and muscles to try to resuscitate ones that had died. This was demonstrated on a cat in the mid 1700s. The animal had experienced a fall in blood pressure, then a single induction shock was sent into its heart. This caused a more rapid series of ventricular beats. Individual beats improved in strength as compared with the spontaneous beats occurring before and after. Also, in 1949, Dr. Wilfred G. Bigelow, a Canadian surgeon, did an experimental operation on a dog whose heart stopped. He gave the left ventricle a poke with a probe, and all 4 chambers responded.

            In 1864, Althaus, who was a German theologian, reported successful resuscitation of cardiac arrest victims by electrical currents applied through a transthoracic needle. Then in 1899, Prevost and Batelli, who were physiologists, demonstrated that electrical currents could cause ventricular fibrillation that could often be reversed by another stimulus of either alternating or direct current.

            Then came stimulation of the human heart. This was vital in this turning point because the goal of the pacemaker was to it could be used by humans, not only animals. In 1932 and 1947, Kounwehowen and Beck, who were also physiologists, made efforts, and those efforts made electrical defibrillation widely used in clinical settings. Initial experiences however, did not lead to immediate clinical trials. When stimulation of the heart occurred, shocks were employed. These shocks were strong and sufficient enough to excite powerful contraction in the voluntary muscles of the heart.

            Cardiologist, Albert Hyman, and his engineer brother patented the artificial pacemaker in 1930. This device was operated by a hand crank and spring motor which turned a magneto, which produced electricity. This device was used in the New York area and received press coverage. However, the medical community did not accept it. Then in 1932, Albert Hyman developed a machine for controlled electrical stimulation of the heart. He named this the “Artificial Cardiac Pacemaker”. During his promulgation of the artificial pacemaker, he claimed to have designed and constructed different models. Siemens, which is a very old German engineering company still in existence today, back then did, was determined that the pacemaker would never accomplish its intended job or function. It was actually believed that all actual models of the Hyman pacemakers had been destroyed in World War II.

            Now we move on to defibrillation. This is also a vital part in why this was a big turning point because defibrillation goes hand in hand with pacing and the function of the pacemaker. If ventricular fibrillation develops in hearts that are relatively normal, then defibrillation may be lifesaving. This is especially helpful during operation. During periods before regular hear rhythms are restored, the heart must be exposed and rhythmically massaged in intervals. If defibrillation is necessary during an operation, the heart is placed between two large electrodes and currents are sent to the heart. A series of shocks is necessary to accomplish defibrillation. If this treatment is successful, the ventricles cease fibrillation and remain in a standstill momentarily before rhythm is established. Massaging of the heart is then continued until the vigor of the heartbeat is successful to empty the cardiac cavities of blood. This was shown in the mid-late 1900s, Dr. Claude Beck, who was a cardiac surgeon, was operating on a 14 year-old boy. During this operation, the boy’s heart stopped. Beck massaged his heart, multiple shocks were applied and eventually, contractions were seen.

            Jack Hopps, a Canadian medical researcher, first built the cardiac stimulator defibrillator in 1950. This device used 60-Hz currents at voltages up to 220V to arrest fibrillation through the open chest. This instrument’s main function is to stimulate a stopped heart to resume beating and regulate the heartbeat.

            In 1958, first attempts at pacing with an implantable pacemaker were made in Sweden. Due to the fact that pacemakers are implanted in current day, this event was significant in the turning point. To reduce the amount of infection, a totally implantable battery-powered pacemaker/radiofrequency stimulator was introduced that could be externally programmed in 1959. However since infection was still a risk, another pacemaker was developed at the initiative of Dr. Senning, a cardiovascular surgeon. This device was small enough to implant subcutaneously in the epigastrium, which is the upper central region of the abdomen. It was thought that the pulse generator should deliver pulses about two volts and an impulse period of 1.5 milliseconds at a rate of 70-80 per minute. The first apparatus had two electrode wires and it was unsuitable as an electrode. It ceased to stimulate and patients went into heart block.

             On February 3, 1960, Dr. Robert Rubio implanted the battery-operated pacemaker, which was invented by C. Walten Lillehei in 1957. This patient later died because of an infection, which developed on the thoracic incision site. The National Society of Professional Engineers recognized Dr. Lillehei for creating one of the 10 outstanding engineering advances of the 20th century.

           Prototypes of the pacemaker were also made for laboratories so they could study the threshold of heart pacing, waveform studies and pulse widths. In the mid 1900s, transistors and reliable batteries permitted the design of pacemakers of an implantable size. Prototypes included a transformer-type pacemaker. This consisted of an external transmitting coil, an internal receiving coil, and a myocardial electrode. Both transmitting and receiving coils created the effective electromagnetic coupling. From 1964-1968, this pacemaker was used in 14 patients at the Tokyo University Hospital. The average period of usage was 40 months.

           After 2 years of experimental work in the animal laboratory, a 77 year-old patient with complete heart block was referred to a doctor. The elderly man had an operation done in June 1960 and his heart block was successfully corrected. In the late 1960s, experimental implantation on a dog was carried out for intermittent pacing. And finally, in the late 1960s, the first cardiac pacemaker was implanted by H.K. Sylosch Düsseldorf using the Greatbach fixed pacemaker.