Difference Between Stable and Unstable Angina

Stable angina and unstable angina are two clinical entities in cardiology caused by reduced blood supply to the heart muscle. High serum cholesterol level leads to deposition of cholesterol on the blood vessel wall. This is called atheromatous plaque formation. When this happens in the blood vessels supplying the heart muscle it is called coronary atherosclerosis. The top of the plaque may get damaged, and blood clots may form occluding the already compromised artery, and the blood supply to the heart diminishes.This is called myocardial ischemia.

What is Stable Angina?

The definition of stable angina is ischemic type chest pain occurring with exertion, not accompanied by electrocardiogram changes. It features chest pain, sweating, shortness of breath. The chest pain is a severe, sudden onset, tightening pain that radiates down the medial side of the left arm, up the neck and the left side of the jaw. Walking and exertion aggravates it while rest and nitrates relieve it. It usually lasts less than 20 minutes. Electrocardiogram does not show any ischemic changes. It is diagnosed with the characteristics of the chest pain alone. If you get these symptoms, get yourself admitted to the nearest hospital because serious heart attacks also present the same way. You cannot differentiate between angina and heart attack with symptoms alone. Doctors need an electrocardiogram to differentiate. In the emergency room, the doctors will give you stat doses of aspirin, clopidogral and a statin. These drugs may be prescribed for you to use long term. Stable angina is a sign of narrowed arteries supplying the heart muscle. It is a risk factor for a more serious heart attack.

What is Unstable Angina?

Unstable angina is an ischemic type chest pain occurring at rest, not accompanied by electrocardiogram changes of an infarction. Its symptoms are similar to stable angina. The chest pain is a severe, sudden onset, tightening pain that radiates down the medial side of the left arm, up the neck and the left side of the jaw. Walking and exertion aggravates it while rest and nitrates relieve it. It usually lasts less than 20 minutes. Immediate hospitalization is essential. Electrocardiogram does not show any ischemic changes.  Emergency management is similar to stable angina. Stat doses of aspirin, clopidogral, and a statin, followed by a long term prescription are in the usual regimen. Unstable angina suggests a more serious block in arteries supplying the heart muscle.

Stable vs Unstable Angina

• Stable angina occurs with exertion while unstable angina comes on while the patient is at rest.

• Stable angina occurs because the blood going to the heart muscle is not enough to cover for the extra workload in exercise. Unstable angina occurs because a blood clot blocks an artery supplying the heart muscle.

• The lack of blood supply in unstable angina is short lived, and it is not enough to damage the heart muscle permanently.

• Electrocardiogram does not show any ischemic changes in both stable and unstable anginas, but there may be a rapid heart rate, non-specific ST segment changes.

• The risk of developing further heart attacks in the future is higher with unstable angina than with stable angina. Individuals with diabetes, high blood pressure, high serum cholesterol levels and family history of said diseases are at a higher risk.