Due to atherosclerosis, a layer of cholesterol gets accumulated inside the arteries and forms a plaque. Sometimes this plaque ruptures acutely which results into a blood clot formation and cessation of blood circulation inside the artery. Just as the water-supply stops when some rubbish gets trapped inside the water pipeline ! In the absence of continuous supply of blood and oxygen, muscles of the heart cannot work effectively and start losing life within only a few minutes. Depending on the site of the block in the artery, this damage is caused in a small or larger part of the heart. If the blockage occurs in the initial part of an important coronary artery, millions of heart cells get destroyed and it results in a severe heart attack. If the blockage occurs in a distal or remote part of an artery, only a small part of the heart dies and damage caused to the heart is less.
Due to continuous beating of the heart, significant shear stress (mechanical forces) is experienced in the initial parts of three main coronary arteries. That’s the reason why blockage are generally created in proximal parts, and when they rupture, they lead to major heart attacks.
In many cases of heart attack, patients do not have prior heart problems or symptoms. A sudden earthquake ! That is why, not only the heart but also body and mind of the patient become incapable to bear this blow.