Coronary heart disease
Summary
Coronary heart disease (CHD) is a life-threatening condition that occurs w hen the arteries that supply the heart muscle with oxygen-rich blood (coronary arteries) become blocked.
– CHD is usually caused by a condition called arteriosclerosis in which plaque builds up along the innermost layer of the coronary arteries.
– As the coronary arteries narrow, angina (chest pain) may result, especially on exertion. The risk of heart attack also increases.
– A complete medical history and a physical examination is usually the first step in the diagnosis of CHD. Other diagnostic procedures (e.g. electrocardiogram, stress test, coronary arteriogram or nuclear scanning) may follow.
– Treatment may involve lifestyle changes, coronary angioplasty or coronary artery bypass surgery.
– CHD is, to a large extent, preventable.
Alternative names
Coronary artery disease; arteriosclerotic heart disease
What is coronary heart disease?
Coronary heart disease is a life-threatening condition that occurs w hen the arteries that supply the heart muscle with oxygen-rich blood (coronary arteries) become blocked.
CHD affects men and women and, worldwide, more than 17.5 million people die of the condition every year. Globally, CHD is the leading cause of death.
What causes it?
CHD is usually caused by a condition called arteriosclerosis in which plaque (made up of fat, cholesterol, calcium and other substances found in the blood) builds up along the innermost layer of the coronary arteries. This process, which may already begin in childhood, progressively narrows the arteries and reduces blood flow to the heart muscle.
The build-up of plaque also increases the risk of blood clots forming on top of the plaque, which can partially or completely block blood flow. It may also deform the arterial wall, increasing turbulence and resistance to blood flow.
Further damage to the inner linings of the coronary arteries can be caused by cigarette smoking.
Factors that increase the risk of CHD include:
– High blood glucose (blood sugar) levels: fasting plasma glucose >100mg/dL (5.6 mmol/L)
– High blood pressure: systolic blood pressure > 130mmHg or diastolic blood pressure > 85mmHg
– High LDL ('bad') cholesterol levels: >3mmol/L
– Low HDL ('good') cholesterol levels: < 1mmol/L
– High levels of triglycerides: >1.7 mmol/L
– Inflammation: low adiponectin levels and/or high C-reactive protein levels
– Abdominal obesity: waist circumference >102cm for men or >88cm for women
– Insulin resistance
– Physical inactivity
– Smoking
– Family history of CHD
What are the symptoms?
As the coronary arteries narrow, angina (chest pain) may result, especially on exertion. The risk of heart attack also increases, often due to the formation of a blood clot forming on top of a previous narrowing. In a heart attack (myocardial infarction), a portion of the heart muscle actually dies.
Signs of a heart attack include:
– a pressing, centrally located chest pain, which may be felt in the arms and hands as tingling or numbness
– shortness of breath
Less characteristic features include:
– sweating
– nausea
– dizziness or light-headedness
– palpitations
– pain in the jaw or shoulder/upper arm
Note, however, that some people with CHD may experience no symptoms. This applies particularly to diabetics, who seldom experience angina. Women generally also do not experience classical symptoms: this leads to CAD not being recognized in the early stages. By the time it is diagnosed, there is often so much damage done that women tend to have a worse prognosis that men.
How is it diagnosed?
A complete medical history and a physical examination is usually the first step in the diagnosis of CHD.
Hereafter, a combination of diagnostic procedures may follow. These include:
– Electrocardiogram. This is a recording of the electrical activity of the heart, which may point to abnormal rhythms and possible heart damage.
– Exercise electrocardiogram('stress test'). With this test, the patient is required to walk on a treadmill while their heart, breathing and blood pressure are monitored.
– Coronary arteriogram. This involves an X-ray examination of an artery that has been outlined by the injection of a contrast agent. It points to narrowing, occlusions and other abnormalities in specific arteries.
– Nuclear scanning. Here, radioactive material is injected into a vein and observed by means of a camera. The information is transferred to a computer and an image is created.
How is it treated?
1.) Controlling the risk factors
Making lifestyle changes is the first course of action. These include smoking cessation, losing weight, following a balanced diet, and doing a moderate amount of exercise (see 'Prevention' below).
2.) Medical procedures
These may include:
– Coronary angioplasty. This permits more blood flow to the heart. Several options, including balloon angioplasty, atherectomy, laser angioplasty and the insertion of a coronary artery stent, are available.
– Coronary artery bypass surgery. This involves the attachment of a piece of a vein from the leg or artery from the chest or wrist to the coronary artery above and below the narrowed area or blockage – a process which allows blood to bypass the blockage.
What is the prognosis?
The outlook of CHD depends on many factors. The prognosis is generally good for people with stable angina, who take their medication as prescribed, eat correctly and exercise regularly.
H owever, there is a 10% mortality risk within 30 days in people who have had a heart attack. The sooner the patient receives appropriate treatment, the lower the mortality risk.
When to call your doctor
If there are symptoms of a heart attack, call the nearest emergency service immediately. Emergency treatment can prevent damage to the heart muscle and death.
A chest pain which occurs with exertion, stress, or after eating a large meal and which goes away with rest may be a heart attack or angina. Such pain is a warning sign of heart disease. Call the nearest emergency services immediately for urgent medical attention.
How can it be prevented?
CHD is, to a large extent, preventable. The following steps could cut your risk:
– Be acutely aware of your risk for CHD and consider getting genetic testing done as there is a strong hereditary link.
– Know your numbers. Go for regular tests to determine your waist circumference, as well as your blood-glucose, cholesterol, triglyceride and blood-pressure levels.
– Quit smoking.
– Lose weight. Obesity is associated with a number of risk factors for CHD. These include hypertension, insulin resistance and glucose intolerance, hypertriglyceridaemia and reduced HDL cholesterol.
– Follow a healthy diet. Cholesterol production and plaque build-up is closely linked to fat intake and metabolism. Just by controlling intake, especially of fat, your total cholesterol levels can be lowered by 10-20%. Limit your total daily fat consumption to 30% or less of total kilojoule intake. Concentrate on eating less saturated fat and trans fatty acids and more polyunsaturated and monounsaturated fat. Also aim to eat less than 200mg cholesterol per day.
– Do moderate exercise, at least 3-4 times per week.
The information provided in this article was correct at the time of publishing. At Mediclinic we endeavour to provide our patients and readers with accurate and reliable information, which is why we continually review and update our content. However, due to the dynamic nature of clinical information and medicine, some information may from time to time become outdated prior to revision.
