What makes calcium channel blockers effective for treating angina?

Calcium channel blockers are effective in treating angina primarily due to their potent vasodilatory effects on coronary arteries. These medications work by inhibiting the influx of calcium ions into vascular smooth muscle and cardiac muscle, leading to relaxation of the muscle and dilation of blood vessels. This vasodilation decreases vascular resistance and increases blood flow to the heart muscle, enhancing the delivery of oxygen-rich blood during times of increased demand, such as physical activity or stress.

By improving blood flow to the heart, calcium channel blockers help alleviate the symptoms of angina, which is often triggered by inadequate oxygen supply to the heart muscle. The reduction in coronary artery spasm can also help prevent episodes of angina.

Other choices, while related to cardiovascular effects, do not directly address the key mechanism by which calcium channel blockers relieve angina symptoms. For instance, increasing heart rate would actually increase myocardial oxygen demand, which is counterproductive in the context of angina. Reducing fluid retention is more associated with other classes of antihypertensive agents, such as diuretics, rather than with calcium channel blockers. Inhibition of heart contractility can be a side effect of some calcium channel blockers, which might help reduce the workload of the heart, but the primary mechanism