industrialised world. it exacts a significant mortality with approximately 70,000 to 90,000 sudden cardiac deaths each year in the united kingdom, and survival rates are only 2%. the majority of these deaths are due to ventricular fibrillation secondary to myocardial infarction, or "heart attack". during ventricular fibrillation, cardiac output drops to zero, and, unless remedied promptly, death usually ensues within minutes. history lyman brewer suggests that the first recorded account of ventricular fibrillation dates as far back as 1500 bc, and can be found in the ebers papyrus of ancient egypt. an extract, recorded 3500 years ago, states: "when the heart is diseased, its work is imperfectly performed: the vessels proceeding from the heart become inactive, so that you cannot feel them … if the heart trembles, has little power and sinks, the disease is advanced and death is near." a book authored by jo miles suggests that it may even go back farther. tests done on frozen remains found in the himalayas seemed fairly conclusive that the first known case of ventricular fibrillation dates back to at least 2500 bc. whether this is a description of ventricular fibrillation is debatable. the next recorded description occurs 3000 years later and is recorded by vesalius, who described the appearance of "worm-like" movements of the heart in animals prior to death. the significance and clinical importance of these observations and descriptions possibly of ventricular fibrillation were not recognised until john erichsen in 1842 described ventricular fibrillation following the ligation of a coronary artery (erichsen je 1842). subsequent to this in 1850, fibrillation was described by ludwig and hoffa when they demonstrated the provocation of ventricular fibrillation in an animal by applying a "faradic" (electrical) current to the heart. in 1874, edmé félix alfred vulpian coined the term mouvement fibrillaire, a term that he seems to have used to describe both atrial and ventricular fibrillation. john a. macwilliam, a physiologist who had trained under ludwig and who subsequently became professor of physiology at the university of aberdeen, gave an accurate description of the arrhythmia in 1887. this definition still holds today, and is interesting in the fact that his studies and description predate the use of electrocardiography. his description is as follows: "the ventricular muscle is thrown into a state of irregular arrhythmic contraction, whilst there is a great fall in the arterial blood pressure, the ventricles become dilated with blood as the rapid quivering movement of their walls is insufficient to expel their contents; the muscular action partakes of the nature of a rapid incoordinate twitching of the muscular tissue … the cardiac pump is thrown out of gear, and the last of its vital energy is dissipated in the violent and the prolonged turmoil of fruitless activity in the ventricular walls." macwilliam spent many years working on ventricular fibrillation and was one of the first to show that ventricular fibrillation could be terminated by a series of induction shocks through the heart. the first electrocardiogram recording of ventricular fibrillation was by august hoffman in a paper published in 1912. at this time, two other researchers, george ralph mines and garrey, working separately, produced work demonstrating the phenomenon of circus movement and re-entry as possible substrates for the generation of arrhythmias. this work was also accompanied by lewis, who performed further outstanding work into the concept of "circus movement." later milestones include the work by w. j. kerr and w. l. bender in 1922, who produced an electrocardiogram showing ventricular tachycardia evolving into ventricular fibrillation. the re-entry mechanism was also advocated by deboer, who showed that ventricular fibrillation could be induced in late systole with a single shock to a frog heart. the concept of "r on t ectopics" was further brought out by katz in 1928. this was called the "vulnerable period" by wiggers and wegria in 1940, who brought to attention the concept of the danger of premature ventricular beats occurring on a t wave. another definition of vf was produced by wiggers in 1940. he described ventricular fibrillation as "an incoordinate type of contraction which, despite a high metabolic rate of the myocardium, produces no useful beats. as a result, the arterial pressure falls abruptly to very low levels, and death results within six to eight minutes from anemia of the brain and spinal cord". spontaneous conversion of ventricular fibrillation to a more benign rhythm is rare in all but small animals. defibrillation is the process that converts ventricular fibrillation to a more benign rhythm. this is usually by application of an electric shock to the myocardium and is discussed in detail in the relevant article.