Angina pectoris:
It is type of condition in which heart lacks blood supply resulting in severe constricting pains in the chest. The pain of angina pectoris often develops and spreads from the precordium of the heart to a shoulder (usually left) and down in the arm (of left side).
Cause of angina:
It may be due to ischemia of the myocardium usually produced as a result of coronary heart disease.
Types of angina:
It may be of different types:
1. Classical angina:
This is also referred to as angina of effort or exercise induced or stable angina or typical angina.
Symptoms:
It is marked by feeling of squeezed chest as well as burning in the chest.
Mechanism:
It may be due to blockage of the large coronary vessels leading to reduced coronary perfusion. This blockage may be caused by lipid deposits in the vessels.
2. Variant angina:
It is also called as vasospastic or prinzmetal’s angina. This often occurs at rest.
Mechanism:
1. It is caused by coronary artery spasm.
2. It also occurs as a result of less flow of blood to the muscles of the heart.
3. Unstable angina:
It occurs fewer than other types of angina and its cause is not among other causes of angina. It is in between stable angina and myocardial infarction. This often occurs at night in bed.
Stable Angina ---------- Unstable Angina ----------- Myocardial Infarction
Treatment of angina:
Angina is treated by any/both of the following mechanisms:
1. Promote perfusion of the muscles of the heart
2. Less metabolic demand of the muscles of the heart
Less requirement of oxygen in patients with angina is done by one of the following mechanisms:
1. Less generation of impulses in SA node
2. Reduced conduction velocity in AV node and Purkinje cells
3. Reduced contractions of the heart muscles
4. Reduced cardiac output.
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