What effect do beta-blockers have on the heart?

Beta-blockers primarily decrease heart rate and blood pressure by blocking the action of adrenaline (epinephrine) on beta-adrenergic receptors, particularly in the heart. When beta-adrenergic receptors are stimulated, they typically increase heart rate and force of contraction. By inhibiting these effects, beta-blockers lead to a reduction in heart rate, which is beneficial for conditions like hypertension and arrhythmias.

Additionally, the decrease in heart rate leads to lower myocardial oxygen demand, making beta-blockers especially useful in managing cardiovascular conditions such as angina and heart failure. Along with reducing the heart's workload, these medications also help in lowering blood pressure, which can further prevent strain on the heart and reduce the risk of more serious complications like heart attacks.

While beta-blockers can have other beneficial effects, such as stabilizing heart rhythm and influencing vascular tone, their primary and most well-documented effects in the context of heart function are the decrease in heart rate and blood pressure.