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.
Left untreated, ventricular fibrillation is rapidly fatal as the vital organs of the body, including the heart, are starved of oxygen, and as a result patients in this rhythm will not be conscious or responsive to stimuli. Prior to cardiac arrest, patients may complain of varying symptoms depending on the underlying cause. Patients may exhibit signs of agonal breathing, which to a layperson can look like normal spontaneous breathing, but is a sign of hypoperfusion of the brainstem.It has an appearance on electrocardiography of irregular electrical activity with no discernable pattern. It may be described as coarse or fine depending on its amplitude, or as progressing from coarse to fine V-fib. Coarse V-fib may be more responsive to defibrillation, while fine V-fib can mimic the appearance of asystole on a defibrillator or cardiac monitor set to a low gain. Some clinicians may attempt to defibrillate fine V-fib in the hope that it can be reverted to a cardiac rhythm compatible with life, whereas others will deliver CPR and sometimes drugs as described in the advanced cardiac life support protocols in an attempt to increase its amplitude and the odds of successful defibrillation. Causes
Ventricular fibrillation has been described as "chaotic asynchronous fractionated activity of the heart" (Moe et al. 1964).