The heart is the central organ of the blood-vascular system and consists mainly of a hollow muscle of conical form that pumps blood into a set of outgoing vessels - arteries and through them to all parts of the body.

The heart has double circulation, both functional and nutritional. The functional circulation consists of all heart chambers and the great vessels of the heart. These parts serve for conducting the blood through the heart.

The nutritional circulation brings blood to all parts of the heart, because the heart, as with every organ in the human body, needs the delivery of oxygen and nutrients. There are several anatomical variations, but, in general, the two main arteries, the left and right coronary arteries originate from the aorta, just above the aortic valve.

The right coronary artery runs backwards, just between the left and right ventricle, to the apex where its small branches anastomose with branches from the left coronary artery. The left coronary artery runs forwards onto the anterior surface of the heart. It divides then into two arteries. The left anterior descending artery runs into the sulcus atrioventricularis anterior, just between left and right ventricle, to the apex, where its small branches anastomose with the right coronary artery. The second branch, the left circumflex artery, runs around the left margin of the heart on the posterior surface. The veins of the heart follow the coronary arteries at the beginning, but then join together on the posterior surface as the sinus coronarius, which ends in the right atrium.

Atherosclerosis (ath-er-o-skler-O-sis) is a disease in which plaque (plak) builds up on the insides of your arteries.Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. Over time, plaque hardens and narrows your arteries. The flow of oxygen-rich blood to your organs and other parts of your body is reduced.

This is the first step in the reduction of blood supply to heart when the atherosclerosis occurs in the coronary arteries.This does'nt happen suddenly.It takes years to build.It might happen fast if the diet has more of fat,physical inactivity,diabetes,stress,etc.

Although the disease process tends to be slowly progressive over decades, it usually remains asymptomatic until an atheroma obstructs the bloodstream in the artery. This is typically by rupture of an atheroma, clotting and fibrous organization of the clot within the lumen, covering the rupture but also producing stenosis, or over time and after repeated ruptures, resulting in a persistent, usually localized stenosis.When the stenosis crosses over 60% of the lumen it results in ischemic heart disease .Angina is the pain ocurring when the heart does'nt receive enough blood and oxygen in the event of exertion.

Acute coronary disease is caused by disruption of a vulnerable atherosclerotic plaque leading to thrombosis.The rupture in the plaque stimulates the clotting mechanism.This causes the formation of clot inside the lumen which is thrombosis.The thrombus obstructs the flow of blood through the blood vessel completely and causes the heart muscle to suffer ischaemia .Eventually leading to infarction ie death of the muscle tissue.If intervened and the clot dissolved it saves the heart and the patient.