This article explains why beta blockers are used to treat angina. It also covers what effect beta blockers have on angina, as well as potential side effects.
Why Are Beta Blockers Used for Angina?
In stable angina, one or more of the coronary arteries are partially blocked by an atherosclerotic plaque, which is made up of fat and other substances.
Typically, the heart muscle supplied by the impacted artery gets enough blood flow during periods of rest. But during exercise or periods of stress, the partial blockage prevents the blood flow from increasing enough to supply the heart with needed oxygen. As a result, angina occurs.
In individuals with stable angina, beta blockers are considered first-line therapy.
Beta blockers work by blocking the effect of adrenaline on the heart. This results in two major benefits including:
Slowing of the heart rate, in particular during periods of exercise or stress Reducing the force of heart muscle contraction
Both of these reduce the amount of oxygen needed by the heart muscle. As a result, angina and ischemia, which is when there is not enough blood flow to an organ, are delayed or prevented.
What Is the Effect on Angina?
Beta blockers have several effects on angina:
Beta blockers are often effective in improving the intensity or duration of exercise that can be done without developing ischemia or angina. In individuals with angina who have had a heart attack, beta blockers have been shown to reduce the risk of having another one. Studies suggest that beta blockers are helpful in preventing death related to heart attack or heart failure (when the heart doesn’t pump enough blood) in those with stable angina.
What Are the Side Effects of Beta Blockers?
In general, beta blockers are considered safe to take. Lower doses are associated with reduced side effects.
Common side effects of beta blockers may include:
Fatigue, or low energy Weight gain Shortness of breath Dizziness Headache Upset stomach
There are different types of beta blockers available. In some heart conditions, certain beta blockers are not recommended. For example, in individuals with vasospastic angina, which describes when there is a spasm in the coronary artery, certain beta blockers can occasionally cause more spasms.
Many of these side effects may be avoided by using beta blockers that work primarily on the heart itself, also known as cardioselective beta blockers. Unlike other beta blockers, these tend to have little effect on the blood vessels and lungs. Examples of these beta blockers include Tenormin (atenolol) and Lopressor (metoprolol tartrate).
Summary
Beta blockers are used to block the effect of adrenaline on the heart, particularly during exercise. This results in a slowed heart rate, as well as the reduced force of the heart muscle contraction. These effects help delay or prevent both ischemia and angina.
Beta blockers may also reduce the risk of having another heart attack, as well as preventing heart condition-related death. These medications are generally well tolerated.
