What events lead up to a heart attack?

Also, how does ventricular fibrilation work and what are its dangers?

What events lead up to a heart attack?opera singer

A heart attack is myocardial ischemia due to imbalance between oxygen demand and oxygen supply to the heart. Oxygen demand depends on the amount of work done by the heart, which depends on four factors, heart rate, contractility, preload (amount of filling) and afterload (amount of resistance to flow). It is increased in cases of exercise, emotions, stress, and after heavy meals. Oxygen supply is decreased in many conditions but most important is coronary artery disease in which one or more coronary arteries are narrowed by atheromatous plaques. This is precipitated by diabetes mellitus, hypertension, hyperlipidemia, and smoking. Other conditions causing decreased blood supply to the heart include severe aortic stenosis, shock, aortic aneurysm involving coronary arteries, etc.

Ventricular fibrillation is the change of heart rhythm (called sinus rhythm) to a disorganized rhythm where every segment acts individually unlike the normal rhythm where both atria contract followed by both ventricles leading to the pumping of blood. Heart appears as if fibrillation, or in my opinion, dancing. The main causes are myocardial ischemia, Wolf-Parkinson-White syndrome, and some medications. The result is loss of cardiac pumping (it is a form of cardiac arrest) and death will occur within few minutes if CPR was not started.

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What events lead up to a heart attack?

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