What is Coronary Heart Disease?
1.4 The term cardiovascular disease (CVD) refers to any disease that affects the cardiovascular system, principally coronary heart disease (CHD), vascular diseases of the brain and kidney and peripheral arterial disease. Although cardiovascular disease usually affects older adults, its antecedents, notably atherosclerosis, begin in early life, making primary prevention efforts necessary from childhood
1.5 CVD can affect people of all ages and population groups including women and children. Men are at greater risk of heart disease than menopausal women. Once past menopause, it has been argued that a woman’s risk is similar to a man’s.
1.6 Although technically speaking Coronary Heart Disease (CHD) can refer to any ailment afflicting the heart, we generally use it to identify the problems that arise when the blood flow to the heart is clogged or blocked and it suffers injury called “myocardial infraction” and commonly known as “heart attack”.
1.7 CHD is an “insidious” killer that takes 10-20 years to develop, often striking without warning. According to experts the so called “silent” heart attacks, which come out of the blue, in almost half of all heart attacks are either completely asymptomatic or have mild symptoms which the patient dismisses as indigestion or heartburn. Silent heart attacks may strike anyone, but people most likely to experience them are those who had a prior heart attack, individuals who have diabetes and elderly patients with high blood pressure. So identifying risk factors early in healthy people is a must to delay disease and prevent death.
1.8 The damage to the heart arteries or its precursors is usually initiated fairly early in life or childhood and progresses slowly into adulthood. The disease process comes to light only when the blockage in the artery(ies) is severe enough to interfere in the functioning of the heart muscle. In keeping with the principles of hydrodynamics, blood flow through a blood vessel is not usually affected unless the narrowing is at least 50% or more! Once the blockage assumes a particular size, the patient would first begin to feel chest discomfort during exercise, recogised as angina. Angina means coronaries are unable to supply adequate amount of blood to the heart muscle as required by it. With increasing blockages the severity of symptoms increases till the patient begins to experience symptoms even at rest. If at any point the blockage is complete, a heart attack will ensue. All patients do not follow this orderly course. In some cases, the disease may come to attention only with a heart attack out of the blue, without warning; there are all kinds of variations in between. The point to understand is that the individual remains unaware of the disease before symptoms appear. Just because the patient was feeling alright does not mean that there was no disease.
1.9 Heart Attack or Myocardial Infraction occurs due to a complete obstruction or reduced blood flow in one of the coronary arteries resulting in lack of blood through the artery. Though the symptoms of a heart attack can occur suddenly without warning, it is a result of a slowly developing disease “atherosclerosis” of the coronary arteries.
1.10 In atherosclerosis, coronary arteries can easily become roughened, narrowed or blocked by years of accumulated “debris” we call plaque. Made up of dead immune cells, fat, cholesterol, and other elements, plaque can form a dam across an artery, slowing the flow of blood. The dam itself may not cause a serious problem, if enough blood still manages to get through. The plaque can rupture any time due to inflammation and result in the formation of thrombus or blood clot. If the blood clot drifts through arteries and gets stuck at the dam: now the passage is completely blocked. Starved of oxygen, the part of the heart muscle fed by this artery will die. Lay people call it a “heart attack”; physicians refer to it as a “myocardial infraction” or “coronary thrombosis”.