Video narration
How can a heart attack be dangerous if the heart has not stopped? Think of a blocked drain: when flow is cut off, whatever is downstream goes without what it needs. In your heart, the stakes are living muscle. A clot can block a coronary artery, interrupting oxygen-rich blood to part of the heart. The danger is not that the heart stops beating. Heart muscle is being starved. Without oxygen, muscle begins to suffer injury, and the longer blood flow is interrupted, the more damage becomes permanent. That is why suspected symptoms demand immediate emergency medical care. Symptoms vary, so do not wait until you are certain; only medical professionals can diagnose it. Myocardial infarction means heart-muscle injury caused by interrupted blood flow. So, what is a heart attack? It is the heart losing blood and oxygen, with every minute without restored flow risking more permanent damage.