Heart attack, or cardiac arrest, became a leading cause of death after the turn of the century. Defibrillation is one of the most important medical advances of the twentieth century. Defibrillation is a critical step in the treatment of cardiac arrest as it can be the only way to restore a normal heart rhythm and save the life of the individual. However, it is important to note that defibrillation is only effective if it is performed quickly and in conjunction with other life-saving measures such as cardiopulmonary resuscitation (CPR). The history of cardiac defibrillation therapy is long and fascinating, spanning several centuries, many countries and continents. The aim of this article was to provide historical information about technical and scientific advances in cardiac devices and the development of today defibrillators. Review of the available literature, historical data, personal contacts, others and personal experience in this field. In 1947, Beck published the first paper describing open chest defibrillation of the human heart. Ten years later, Kouwenhoven demonstrated that the heart could be defibrillated through a closed chest. The first external defibrillator weighed 120 kg and delivered 500 v of alternating current (AC) potential. The mere size of the defibrillator restricted its use to surgical suites or other areas hospital locations. In many cases, cardiac arrhythmias recurred. This was thought to be related to the amount of energy used to defibrillate the heart which it was believed caused myocardial damage. These factors limited the practical application of defibrillators. By 1956, a unit was built that could be wheeled into the emergency room, plugged into a wall outlet, and deliver 1000 volts. By 1962, Lown realized that AC current resulted in a high frequency of cardiac arrhythmias and cardiac damage. A direct current (DC) defibrillator, consisting of a battery, a capacitor to store energy, and a transformer was developed. The therapy spread from operating rooms to coronary care units and emergency departments and in the late 1960s left the hospital and started appearing on mobile intensive care units. The first portable EMS defibrillators (used by paramedics) emerged in the early 1970s. In 1980 the automatic implantable cardioverter-defibrillator was invented. Automated external defibrillators began appearing in the late 1980s allowing the therapy to be delivered by EMTs and lay people. The 'father' of the modern automated external defibrillator (AED), Professor James Francis (1916-2004) was a physician and cardiologist from Northern Ireland who transformed emergency medicine and paramedic services with the invention of the portable defibrillator. Defibrillators are critical resuscitation devices. The use of reliable defibrillators has led to more effective treatments and improved patient safety through better control and management of complications during Cardiopulmonary Resuscitation (CPR). The 75th anniversary of the world's first successful human cardiac defibrillation represents the landmark event that defined the future of cardiovascular medicine and ushered in a new era of advanced cardiac life support.