Ventricular fibrillation is a life-threatening cardiac arrhythmia characterized by rapid and chaotic contractions of the heart’s ventricles, the lower chambers. It can lead to a loss of effective blood circulation and cause sudden cardiac arrest. Immediate medical intervention, typically with defibrillation (electric shock), is necessary to restore a normal heart rhythm and save a person’s life.

In an electrocardiogram (ECG or EKG), ventricular fibrillation (VF) appears as a chaotic, irregular pattern of electrical activity. Instead of the typical organized waveforms seen in a normal ECG, VF shows rapid, irregular, and jagged lines. This irregularity corresponds to the erratic and ineffective contractions of the heart’s ventricles in VF. It’s a critical emergency situation that requires immediate intervention, such as defibrillation, to restore a normal heart rhythm. Early recognition of VF on an ECG is crucial for prompt treatment and the best chance of survival.