Coronary Artery Disease (CAD)
Coronary artery disease (CAD) or otherwise coronary (ischemic) heart disease is a widespread condition, which progresses when there is an insufficient oxygen supply to the muscle tissue of the heart (myocardium).
While the heart pumps needed blood to the body, it also requires a blood supply. Heart muscle gets its blood through two coronary arteries. These two arteries are split into several smaller branches, each nourishing its own part of the heart. These are the only arteries that deliver blood to the heart, therefore if there is an inadequate blood supply (Ischemia), the heart muscle experiences oxygen and nutrient deficiencies and diseases develop.
Ischemic heart disease is one of the most common conditions all over the world, and one of the major causes of death in developed countries. Up to half of the needed blood supply can be blocked without symptoms. It is a silent killer. When the blockage increases up to 70% or more, clinical signs of heart disease can be observed.
The disease develops at different rates with different people. Dormant stages can take turns with acute periods of the disease. It can develop for decades changing from one of its forms to another during this time. If CAD is not treated the heart is not able to function properly, and organs are not supplied with the required amount of blood. This condition is called chronic heart failure. CAD has a number of clinical manifestations and may occur in acute or chronic forms.
There are several forms of CAD that vary with the degree of the oxygen starvation of the heart, duration and speed of onset:
- Asymptomatic forms, or “silent myocardial ischemia”, provoke no complaints in patients;
- Angina of effort or stable angina pectoris – a chronic form manifested by shortness of breath, as well as chest pain induced by physical activity, emotional stress, or some other factors;
- Unstable angina – angina attacks that are much more severe than previous ones, or that are accompanied by new symptoms. Also, increasing attacks signify the aggravation of the disease and may be the precursor of heart attacks;
- Arrhythmic form – declares itself by heart rhythm disorders, with atrial fibrillation being the most common. It occurs acutely and may develop into a chronic form;
- Myocardial infarction (heart attack) – an acute form of the disease, with necrosis of a region of the heart muscle most often caused by a clot of blood or atherosclerotic plaque separated from the wall of a coronary artery which results in a complete blockage;
- Post infarction cardiosclerosis (heart muscle scarring after heart attack)– results from myocardial infarction and affects heart muscles as well as heart valves in most of the cases. Their muscle fibers are not restored as they are being replaced by scar tissue, which cannot perform the function of the muscle tissue. And, as a result, heart function deteriorates, and heart failure as well as arrhythmias develop;
- Sudden cardiac death – a cardiac arrest, in most cases caused by a sharp decrease in the amount of the blood supplied to the heart resulting from the complete blockage of a large artery. This form of CAD includes only those cases when death occurs during one hour after the first impending symptoms appear.
These forms may be combined with one another or overlap. For example, angina is often accompanied with arrhythmia, and then a heart attack happens.