Which of the following can lead to decreased myocardial oxygen demand?

Beta-blocker therapy is known for its ability to decrease myocardial oxygen demand through several mechanisms. These medications work by blocking beta-adrenergic receptors, which helps reduce heart rate and myocardial contractility. By lowering the heart rate, beta-blockers decrease the amount of oxygen that the heart muscle requires during periods of activity or stress. Additionally, they reduce the force of contraction of the heart, further lessening the oxygen demand.

In contrast, increased physical activity has the opposite effect, as it typically raises the heart rate and increases oxygen demand to supply the working muscles. A diet high in saturated fats can contribute to coronary artery disease, which can ultimately increase myocardial oxygen demand due to reduced blood flow to the heart. Smoking cigarettes is also detrimental, as it can cause vasoconstriction and increase heart rate, thereby increasing oxygen demand rather than decreasing it.

Overall, beta-blockers play a crucial role in managing conditions such as angina by effectively reducing the workload and oxygen requirements of the heart, making them a key component in the treatment of angina pectoris and related cardiovascular conditions.