The disorder is rapidly fatal, because the weak, rapid heartbeats pump little or no blood into the circulation. Ventricular fibrillation may be caused by coronary thrombosis, drugs such as digitalis, excess diuretic use, or electric shock. Atrial fibrillation is effectively treated either with digitalis or with other drugs used to bring the rhythm of the heart under control. All such drugs are used under medical supervision. If fibrillation is associated with a thyroid disorder, thyroid treatment is necessary.
Ventricular fibrillation is an emergency treated as a cardiac arrest.
Regular heart rhythm is restored using a special machine that causes defibrillation.