Sudden cardiac arrest caused by ventricular fibrillation is the cause of half of all cardiac deaths. In VF, the heartbeat is fast and chaotic, causing the lower heart chambers, or ventricles, to spasm. Sometimes, a heart attack (blockage of the heart pipes/arteries) can lead to VF. VF is sudden, happens without warning, and stops the heart from working.
The lack of oxygen to the body, especially to the brain, is deadly. Sudden cardiac arrest is caused by an electrical problem. It is not the same as a heart attack (myocardial infarction), which is a circulatory (plumbing) problem caused by clogged blood vessels that cut off the supply of blood to the heart.
Though CPR may help, the only truly effective VF treatment is defibrillation, which uses paddles or electrodes to “shock” the heart back to normal rhythm. Without treatment, the person with VF will pass out suddenly and die.
Ventricular Tachycardia (VT)
Credit: Heart Rhythm Society