What is the primary benefit of beta-blockers in stable coronary artery disease?

• A. Decrease heart rate and myocardial oxygen demand
• B. Increase heart rate
• C. Increase myocardial oxygen demand
• D. Cause vasoconstriction

Answer: (A)

In stable coronary artery disease, the main aim of beta-blockers is to reduce the heart’s oxygen needs to prevent or lessen ischemia during activity. They do this by blocking beta-1 receptors in the heart, which slows the heart rate and reduces contractility. With a slower heart rate, diastolic time lengthens, improving coronary perfusion, and with lower contractility and blood pressure, myocardial wall stress and oxygen consumption fall. That combination directly lowers oxygen demand and helps relieve angina, making it the primary benefit.

Increasing heart rate would raise oxygen demand and can worsen ischemia, so that option isn’t beneficial. Increasing myocardial oxygen demand or causing vasoconstriction would similarly oppose the goal in stable CAD.