Virtual Medical Centre

Angina Pectoris and Unstable Angina

• What is Angina Pectoris and Unstable Angina?
• Who gets Angina Pectoris and Unstable Angina?
• Predisposing Factors
• Progression
• Probable Outcomes
• How Will Angina Pectoris and Unstable Angina Affect Me?
• Clinical Examination
• How is Angina Pectoris and Unstable Angina Diagnosed?
• How is Angina Pectoris and Unstable Angina treated?
• Angina Pectoris and Unstable Angina References
• Drugs/Products Associated with Angina Pectoris and Unstable Angina

What is Angina Pectoris and Unstable Angina?

Angina Pectoris and unstable Angina is a condition of the coronary arteries - the arteries that supply blood to the heart muscle. When the heart is not receiving sufficient blood supply because of the narrowing of the coronary arteries - this causes pain referred to as "angina". The narrowing of the arteries is usually due to a process called "atherosclerosis" or "atheroma", where the walls of the arteries become coated with a fatty plaque over time.

Who gets Angina Pectoris and Unstable Angina?

About 2% of the overall population suffer from angina pectoris as a result of coronary artery disease. The condition is much more common in older patients with the risk factors mentioned below.

Predisposing Factors

There are many risk factors for coronary artery disease:

1. Hypercholesterolaemia (elevated levels of cholesterol in the blood) plays a central role in the development of the plaques.
2. Increased age and being of the male sex.
3. Family history of coronary artery disease.
4. Smoking: The risk is directly related to number of cigarettes smoked.
5. Diabetes mellitus: Abnormal blood sugar levels promote vascular damage and the development of plaques.
6. Hypertension: High blood pressure promotes artery damage which may initiate or exacerbate atherosclerosis causing plaque rupture. It should be noted that hypertension also worsens myocardial ischaemia (heart attack) through the adaptive changes it causes in the left ventricle. In hypertension the heart has to work harder to pump blood and as a consequence the left ventricle becomes hypertrophied (increased muscle bulk). This bulkier muscle then has higher blood requirements. This is theoretically independent of vessel narrowing.

Other, less important risk factors (soft factors) include:

• Stress/anxious personality.
• Obesity.
• Alcohol consumption. It should be noted that a variant form of angina pectoris exists called Prinzmetal Angina which usually occurs at rest. This is not due to atherosclerosis but rather to spasmodic contraction of the coronary arteries. Prinzmetal angina is rare.

Progression

Early in the disease process angina pectoris (chest pain) is experienced when the demand for blood is increased, as in exercise. Angina may progress to become unstable angina. This is when the chest pain becomes more frequent, or begins to occur at rest. However a definitive diagnosis of MI cannot be made because no ECG or enzymatic patterns are seen. Left untreated, over 10% of cases will progress to frank MI (heart attack), consequently when it is discovered it is treated aggressively.