Ventricular fibrillation is a heart rhythm problem that occurs when the heart beats with rapid, erratic electrical impulses. This causes pumping chambers in your heart (the ventricles) to quiver uselessly, instead of pumping blood. Sometimes triggered by a heart attack, ventricular fibrillation causes your blood pressure to plummet, cutting off blood supply to your vital organs.
Ventricular fibrillation, an emergency that requires immediate medical attention, causes the person to collapse within seconds. It's the most frequent cause of sudden cardiac death. Emergency treatment includes cardiopulmonary resuscitation (CPR) and shocks to the heart with a device called a defibrillator.
Treatments for those at risk of ventricular fibrillation include medications and implantable devices that can restore a normal heart rhythm.