History of Defibrillators – How Far We Have Come
Defibrillation is essentially a way of treating life-threatening heart conditions such as ventricular fibrillation (VF), cardiac arrhythmia and ventricular tachycardia (VT) that can lead to cardiac arrest and death.
The process of defibrillation basically delivers an electric shock to the heart that depolarises the heart muscles and coerces them into functioning normally. The machine that is used to deliver the electric shock to the heart in the case of any of the above heart conditions is known as a defibrillator.
Tracing the Timeline of the Evolution of the Defibrillator
Electricity was discovered in the mid-1700s. In 1771, Galvani discovered that electric current could produce contractions in the muscle. At this time, electrical current was used to ensure that a person was actually dead.
In 1775, Peter Christian Abilgaard, a Danish physician, discovered that electricity could stop and restart the heart through his experiments on chickens.
It was in 1850, that Karl Ludwig, a German physician, applied electric current to a dog’s heart and stimulated ventricular fibrillation causing the heart to palpitate.
In 1888, John Mac William, the British physiologist suggested that ventricular fibrillation could cause sudden death. In 1899, F. Batelli and J.L. Prevost, Swiss physiologists discovered that a weak electrical current could cause ventricular fibrillation, while strong voltages applied to the heart directly could stop the ventricular fibrillation and restart the heart.
In 1928, William Kouwenhoven, an Electrical Engineer in the US began the development of defibrillators. In 1933, Kouwenhoven and Langworthy demonstrated the reversal of ventricular fibrillation by internal application of electric current.
For the first time, in 1947, Claude Beck, a US surgeon used the procedure of defibrillation to restore the heartbeat of a 14-year-old boy undergoing a surgical procedure.
The early defibrillators consisted of paddle-type electrodes that delivered 300-1000 volts of electricity. However, the disadvantage of this type of a defibrillator was that it required an open-heart surgery and the defibrillation units were quite large, unwieldy and difficult to transport. They were also not very effective in reversing VF.
In 1950, Eskin and Klimov from the USSR developed a more effective device that could be used to deliver an electric shock of over 1000 volts to the heart via nodes that were applied externally from outside the chest cage.
In 1960, Bernard Lown and William Edmark developed the first portable defibrillator that enabled treatment to be carried outside the hospitals and in 1966 these portable defibrillators were installed in an ambulance and the first Mobile Intensive Care Unit was created by cardiologists Frank Pantrige and John Geddes. These are the portable defibrillators that are used even today.
The Automated External Defibrillator (AED) was introduced in 1978 that contained sensors which could detect the rhythm of the heart during VF and provided instructions electronically. This reduced the training required to operate the defibrillation equipment. And the 80s saw further advancements in the AED technology, enhancing the sensitivity and functions of the equipment.
The latest in the defibrillator technology was the development of the implantable cardioverter defibrillator or ICDs, which was developed in Baltimore at the Sinai Hospital.
Defibrillators have undergone a long evolution process and the various technological advancements have recognised the life-saving capability of electricity and harnessed it in the device we know as the defibrillator, which is indeed a boon to medicine and mankind.
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