Ventricular fibrillation is the final event in the majority of cases of sudden death. The ECG and clinical precursors of ventricular fibrillation are discussed in this article. Ventricular fibrillation usually appears as a consequence of a chain of events that leads to the appearance of this lethal arrhythmia. We review the markers of the vulnerable myocardium prone to ventricular fibrillation, the triggers and modulators that act on this vulnerable myocardium, and the event(s) that constitute the final step preceding this arrhythmia. The final step may be as unique as a sudden waterfall or present as a cascade of successive phenomena.