Health Sciences · Temerty Faculty of Medicine
A disc-like object with an amber-tinted transparent body. One face is mostly covered by a circular metal plate that is marked with information from the manufacturer. Five metallic battery cells are visible within the artifact. Above these are two circuit boards with electronic components facing inwards towards each other.
Above these are two circuit boards with electronic components facing inwards towards each other. A protrusion at the top of the object is a port to which a partial pacing lead is connected. The pacing lead is a length of cable (~9.5cm long) in a clear housing. The cable has been cut, possibly ding removal from a patient.
Visible through the clear material covering the top of the protrusion is a small red label that reads: “150°F”.
Accession Number: 2020.med.26
Alternative Name:
Primary Materials: Plastic, Metal
The writing on the metal face of this item reads as follows: ECTOCOR// STANDBY PACER// RATE 70// 144C7 13499 // CORDIS// MIAMI FLORIDA// U. S. A”
The following number is written in white lettering on a circuit board. It is visible through the clear case: “13499”
Visible through the clear material covering the top of the protrusion is a small red label that reads: “150°F”.
Height = 6.6, Length = 5.6, Width = 2.6.
A pacemaker is an implantable prosthetic device that is used to regulate the natural electrical signal that governs the contractions of the heart. Pacemakers are used in cases when the natural signal is weak, irregular, or impeded. The pacemaker is typically implanted below the collarbone under the skin of the chest with one or more pacing leads entering the heart through a vein.
This is a relatively early commercial implantable pacemaker, likely from the early 1970s. It is a demand, or standby, pacemaker, meaning that it activates when it senses the heart’s natural signal falling below a certain threshold. This example was meant for demonstration rather than implantation.
This artifact is in good cosmetic condition. There are light scratches and wear on every outside surface of this artifact. The pacing lead attached to this pacemaker has been cut.
Associated Instruments:
Manufacturer: Cordis, corp., Miami Fl, U. S. A.
Date of Manufacture: C. Early 1970s.
This artifact belongs to a small collection of items related to cardiac surgery that was collected by Dr. Wilfred Gordon “Bill” Bigelow (1913 – 2005). After his death, the collection was donated to the Cardiovascular Sciences Collaborative Program of the University of Toronto, where it is currently on display.
Edward Shorter, Hugh E Scully, and Bernard S Goldman (2022). The Heartbeat of Innovation : A History of Cardiac Surgery at the Toronto General Hospital. University of Toronto Press.
Kirk Jeffrey and Victor Parsonnet (1998) “Cardiac Pacing, 1960–1985: A Quarter Century of Medical and Industrial Innovation.” Circulation 97, 19: 1978–1991.
Wilfred G. Bigelow (1987). “The Pacemaker Story: A Cold Heart Spinoff.” Pacing and Clinical Electrophysiology 10, 1 : 142–50.
David C. MacGregor, Edward J. Noble, John D. Morrow, Hugh E, Scully, H Dominic Covvey, and Bernard S. Goldman (1977) “Management of a Pacemaker Recall.” The Journal of Thoracic and Cardiovascular Surgery 74, 5 : 657–67.
William H. Walter III (1971) “Radiographic Identification of Commonly Used Pulse Generators—1970.” JAMA : The Journal of the American Medical Association, 215,12, 1974–1975.
Alan S. Trimble, R. O. Heimbecker, and Wilfred G. Bigelow (1964).“The Implantable Cardiac Pacemaker.” Canadian Medical Association Journal 90, 3: 106–10.
This pacemaker is one of three belonging to a small collection gathered by the heart surgeon Dr. Wilfred Gordon “Bill” Bigelow (1913 – 2005). It has a special significance due to Dr. Bigelow’s contribution to the technology’s establishment. This history is recounted in “The Pacemaker Story: A Cold Heart Spinoff”, published by Bigelow in 1987, as well as in the 2022 history of cardiac surgery at Toronto General Hospital by Shorter, Scully, and Goldman.
The earliest developments date to 1949 and involve research by Bigelow and his team into microcirculation and hypothermia in anesthetized dogs. During one experiment, in which he found himself unable to resuscitate a dog in cardiac arrest, Bigelow poked the left ventricle with forceps and found that this made the heart contract. Repeating the gesture produced an effect resembling a heartbeat. The dog was resuscitated and recovered.
This experience inspired Bigelow and his colleague Dr. John Callaghan to experiment with electrical stimulation of the heart. Working first with a commercial Grass signal generator, then with an apparatus built by engineer Jack Hopps of the National Research Council in Ottawa, the group created an external pacemaker that could regulate the heart rate of a dog. The mature design was housed in a table-top electronics console to which was attached a single “bipolar” electrode that was passed through an incision in the neck and through the jugular vein until it reached the sinoatrial node of the heart.
The group presented their work on October 23, 1950 at the meeting of the American College of Surgeons in Boston, Massachusetts. This garnered media coverage, notably a piece in the New York Times. They subsequently provided the circuit diagram to American surgeon Paul Zoll, who used it in the first successful treatment of heart block in humans.
The technology then entered a phase of development with various investigators working towards creating a useful implantable technology. The key development was the availability of early transistors that permitted the creation of a miniaturized, battery powered device. A breakthrough came with the work of Åke Senning of Stockholm who implanted the first practical device in 1958.
Early Cordis pacemakers
The device shown here, likely made in the early 1970s, represents an early generation of commercial implantable pacemakers. It was produced by Cordis Corp. a company based in Miami, Florida, that was selling synchronous pacemakers by 1966. (This standby model was introduced in 1969.)
This example retained many of the components and their corresponding flaws of the early implantable pacemakers. The principal limitation was the mercury-zinc battery cells, first developed during the Second World War. These had an expected life of 3 – 5 years, but often failed much sooner.
Mercury-zinc battery cells also produced hydrogen. The epoxy silicone resin that encases the electronics allows for its release but does not provide a hermetic seal. This was resolved with the introduction of lithium cells in the 1970s. Many problems were also encountered with the early electrical leads, which could fracture or become displaced due to mechanical stresses (Jeffrey and Parsonnet 1998, 1978- 1980).
The early pacemaker experience at Toronto General Hospital
The implantation of transistorized asynchronous pacemakers began at Toronto General Hospital in the early 1960s. These involved the Medtronic Model 5860. By early 1964, 24 pacemakers had been implanted into 23 patients. (See Trimble, Heimbecker, and Bigelow, 1964)
The Toronto General Hospital Pacemaker Clinic was established in 1970. By 1971, nearly 300 pacemaker procedures (including battery changes) had been performed at TGH (Shorter, Scully, and Goldman 2022, 125). In September 1972, a Pacemaker Evaluation Center was established to coordinate with a network of doctor’s offices and clinics in tracking patients.
A major function of the Pacemaker Evaluation Center was to track pacemaker recalls, including a number involving Cordis models. (It is unclear whether this model was implicated.) These began in July of 1973 and increased over subsequent years.