Defibrillation is an integral part of the treatment of malignant arrhythmias, and it is embedded in the international guidelines on cardiopulmonary resuscitation. Since its first clinical use in the 1940s, it has undergone considerable progress, miniaturization, and research-based knowledge of myocardial electrophysiology.
The development of knowledge of myocardial electrophysiology was based on a number of theories and models, but even nowadays the effect of electrical shock on the myocardium is not fully explained. The first defibrillators produced a monophasic shock, but later biphasic shock proved to be more effective and safer in terms of reducing the shock energy.