What are the main reasons for heart disease?
World over, the most important cause of heart disease is narrowing of the blood vessels supplying the heart. This is known as coronary artery disease. The risk factors for coronary artery disease are classified into modifiable and non modifiable. The non modifiable ones are genetic predisposition, age and male gender. As age advances, the chance for narrowing of coronary arteries increases. The modifiable ones are smoking, high cholesterol, high blood pressure and diabetes mellitus (high blood sugar). Stress also contributes to destabilisation of a stable coronary artery disease. If a stable plaque in a coronary artery becomes unstable by fissuring or rupture, a clot forms over it, totally occluding it.
Another important cause of heart disease, especially in children is congenital or birth defects in the development of the heart.
In developing countries, rheumatic heart disease as a consequence of streptococcal (a type of bacteria) infections is also common cause of valvular heart diseases. Infections of the heart by viruses, bacteria and protozoa also contribute to burden of heart diseases.