Causes of a Heart Attack
Although a heart attack or a coronary thrombosis is a sudden event, the catastrophic event itself is an outcome of coronary artery disease that usually takes years to develop.
With advancing years, the blood vessels tend to lose their elasticity. The hardening and the narrowing of the arteries with the deposition of cholesterol and fat in the wall of the coronary arteries interferes with the blood flow. The decrease in the blood supply to the heart commonly leads to angina, the chest pain that arises when the heart muscle is temporarily deprived of sufficient oxygen. A complete blockage of the blood supply to the heart due to the complete blockage of the artery presents itself as a heart attack. While in the vast majority of cases, CAD is the underlying problem for a heart attack, in rare cases, a spasm or sudden constriction of the coronary artery may lead to a heart attack.
ATHEROSCLEROSIS: A PRIME CAUSE
All arteries are pliable and flexible. A typical artery is made up of three different layers: the intima, media and adventitia. The intima is the innermost layer and has a smooth surface. The smoothness of the intima ensures the continuous flow of blood. Deposits of fat and cholesterol in the intima lead to progressive narrowing and occlusion of the artery. This blockage and degeneration of the arteries due to the build up of fatty assets is called Atherosclerosis. If there is Atherosclerosis in the coronary arteries, it may cause a heart attack.
Although heart attacks are rare before the age of 30 years, the process of Atherosclerosis surprisingly starts at a much earlier stage. Deposits of fat and cholesterol in the intima result in the appearance of fatty streaks. Most people unfortunately have fatty streaks in their coronary arteries by the age of 20 years. Fatty streaks slowly increase in size and result in rest areas called fibrous plaques. Over the years the plaques keeps increasing in size. The plaque may rupture and with progressive and repeated bleeding, ulceration, thrombosis hand calcification, the blockage of the arteries continue over the years. This process itself is a slow and gradual one. It may take several years between 10 to 20 years for the fibrous plaques and a significant blockage to develop.
A minor degree of blockage may not really interfere with the blood flow of the heart and hence remain recognized. It is only when the blockage is severe enough to reduce the blood supply of the heart that a person experiences symptoms. During periods of exercise, the heart demand more blood and oxygen supply. With the rapid heart rate and an increase need for the blood supply, the narrowed artery simply does not allow sufficient blood flow to the heart. Under these circumstances, the person commonly experiences chest pain and shortness of breath, which is called an angina attack. Often the person has to slow down and take rest. The need for blood supply diminishes and the pain settles since partial blockage of the artery does allow some blood to pass through the heart. Unfortunately, in most cases the process of Atherosclerosis and plaque formation continues and the partial blockage then turns into complete blockage resulting in a heart attack.
BLOOD CLOTS IN THE CORONORY ARTERY
The blood is made up of red cells, while cells and other small cells called platelets. Normally, the blood is in a fluent state and continues to flow without any interruption. When and if the blood comes in contact with the broken surface for example a ruptured plaque within a wall of a coronary artery several chemicals changes occur which lead to a clot formation. This is a local reaction to bleeding. A similar situation exists when there is a small cut on your finger. When a clot occurs in the coronary artery, it is really dangerous for the heart. The clot may lead to a complete blockage of the artery and causes a heart attack. It is only because of the dangerous and the damages caused by a clot that physician wants to dissolve a clot as soon as possible. The sooner the clot is dissolved, the easier it is for the blood supply to be resumed.