The purpose of antiangianl drug therapy is to:
a. increase myocardial oxygen demand
b. increase blood flow to ischemic myocardium
c. increase blood flow to peripheral arteries
d. decrease blood flow to ischemic myocardium
The correct answer and explanation is:
The correct answer is: b. increase blood flow to ischemic myocardium
Explanation:
Antianginal drug therapy aims to relieve the symptoms of angina pectoris, which is chest pain caused by reduced blood flow and oxygen supply to the heart muscle (myocardium). The primary goal of these medications is to improve oxygen delivery to the ischemic myocardium—the part of the heart muscle suffering from insufficient blood flow.
Angina occurs when the oxygen demand of the heart exceeds the oxygen supply, often due to narrowing or blockage of the coronary arteries. Antianginal drugs work through different mechanisms to restore the balance between oxygen supply and demand.
Some antianginal drugs dilate coronary arteries, allowing more blood and oxygen to reach the ischemic areas. Others reduce the heart’s oxygen demand by lowering heart rate, blood pressure, or myocardial contractility. By either increasing blood flow or reducing workload, these drugs help prevent or relieve angina attacks.
For example, nitrates (like nitroglycerin) cause vasodilation of coronary arteries, improving blood flow directly to ischemic regions. Beta-blockers reduce heart rate and contractility, decreasing oxygen demand. Calcium channel blockers dilate coronary and peripheral arteries, also enhancing oxygen supply.
The other options are incorrect for the following reasons:
- Option a (increase myocardial oxygen demand) is counterproductive because increasing oxygen demand worsens ischemia.
- Option c (increase blood flow to peripheral arteries) is not the main target of antianginal therapy. Although some drugs may have peripheral effects, the primary focus is on coronary circulation.
- Option d (decrease blood flow to ischemic myocardium) would worsen angina by further limiting oxygen supply.
Therefore, the main purpose of antianginal drug therapy is to increase blood flow to the ischemic myocardium, either by improving coronary artery perfusion or by reducing the heart’s oxygen needs. This helps relieve chest pain and prevent myocardial damage.