Life Health Sciences – Science Rules it All

Coronary Heart Disease (CHD) is the most common heart disease in the developed world. In United Kingdom one male in every four males and one female in every five females suffers with CHD during lifetime.  Advancing age and family history of CHD are major risk factors. Other main risk factors for development of CHD include obesity, smoking, increased blood cholesterol level, stress, hypertension and diabetes mellitus. Angina pectoris is one of the most frequent presentations of CHD.   It has two types, stable angina and unstable angina.

Stable Angina
Transient ischemia of heart muscles can occur due to imbalance between supply and demand of oxygen to the heart. The most common reason of it is atheroma of coronary artery. Atheroma formation in coronary arteries lead to narrowing of their lumens thus making them unable to meet increased demand for arterial blood and oxygen supply during activities like physical exertion after heavy meals, walking in the cold and excessive emotional stress.

Symptoms
There is feeling of pain in the central part of chest, a discomfort or difficulty in breathing with exertion or with different forms of stress. The pain is relieved by rest. In some people pain starts when they start walking and latter on it does not come again even with more physical exertion (start up angina). The pain may radiate to one arm, both arm or neck.

Investigations

Electrocardiogram (ECG)
ECG at rest is mostly normal in patients with left main coronary artery disease and even in three main coronary arteries disease. The most important change is ST segment elevation or depression with or without T-wave inversion.
In ECG taken during exercise, T-segment is flat or depressed up to 1 mm shows ischemia. Examining ECG during exercise is used to confirm diagnosis of angina.

Myocardial Perfusion Scanning
This test is useful in patients who are unable to exercise or whose exercise tolerance test is not decisive. The radioactive isotope thallium is injected intravenously and scans are taken at rest and during stress. Perfusion defects present during stress shows myocardial ischemia.

Stress Echocardiography
This technique uses echocardiography of heart to detect ischemic areas of heart muscle. It is superior to ECG.

Coronary Arteriography
This is used when non-invasive tests have failed to diagnose cause of chest pain. This is also helpful for coronary bypass grafting.

Management
Life style changes can help to reduce risk factors, relieve symptoms and improve outcome. These include quitting smoking; normalize body weight, treatment of diabetes and hypertension and regular exercise till point of chest pain. Avoiding heavy exercise and exercise after meals in cold weather protect from angina.

Using sublingual nitrate, before exercise or exertion that can cause angina, help increase revasculrisation of heart. Aspirin in low dosage 75-150 mg a day decreases risk of complications like Myocardial Infarction.  Aspirin inhibits blood platelet aggregation thus inhabits thrombi formation in coronary arteries.

Drug Treatment
Different groups or drugs are used including nitrates, beta blockers, calcium antagonists and potassium channel activators in different combinations.

Other Treatments
These are invasive methods of treatment and include percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG).

Unstable Angina
When angina is rapidly worsening that is angina on rest or with minimum exertion, it is called unstable angina. It may occur when patient has stable angina previously. It occurs when an atheroma plaque in coronary artery ruptures with thrombus formation and coronary artery spasm. This leads to sudden reduction in blood supply to heart muscle. The obstruction may increase or decrease with changes in the plaque and emboli formation.

Investigations
Continuous monitoring of heart by ECG is useful. ST depression, initial ST elevation and T wave inversion are present in unstable angina.
Biochemical markers of cardiac damage are checked by serial measurements of troponin I and T.

Management
Patient needs hospitalization and aspirin, beta-blockers, calcium antagonists, and nitrate are given. PCI and CABG are considered if needed.

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