Which class of drugs primarily relaxes smooth muscle in the heart and vessels for angina treatment?

Calcium channel blockers are the class of drugs that primarily work by relaxing smooth muscle in the heart and blood vessels, making them effective in treating angina. They block the influx of calcium ions into the cells of the heart and the vascular smooth muscle, which leads to vasodilation and a reduction in heart muscle contractility. This decreased contractility lowers the heart's oxygen demand, which is particularly beneficial for patients experiencing angina, as this condition is often characterized by oxygen supply-demand mismatch in the heart.

In addition, by relaxing the arteries, calcium channel blockers can help to reduce blood pressure, further alleviating the work of the heart. This dual mechanism of action—reducing both the heart's workload and enhancing blood flow—makes them particularly useful in the management of angina. Understanding this mechanism is crucial for effective treatment and management of conditions related to the heart and circulation.