Ventricular fibrillation is most often caused by sudden occlusion of the left anterior decending coronary artery by delamination of an atheromatous plaque or develelopement of a clot in that artery due to nonlaminar flow of blood. In other words,..a suddend occlusion of that artery. Also ischemic heart disease is probably one of the most common causes. Drug toxicities such as phenothiazine toxicity. Other causes might include mitral valve prolapse (more common in females). Profound hypothermia can also cause sudden ventricular fibrillation. Sudden rupture of a papillary muscle can cause this condition.
All result in this same ventricular dysrhythmia and sudden death.
Ventricular fib took my dad at 67. The only possibility of survival is if it occurs IN an ambulance, ICU, or ER, as they have around ninety seconds to get the paddles on you or there’s no possibility of resuscitation.
We assume there was no pain, and grateful that it was so fast (for him).