What defines the mechanism of action of calcium channel blockers in treating angina?

The mechanism of action of calcium channel blockers in the treatment of angina centers on their ability to decrease heart rate and workload. These medications work by inhibiting the entry of calcium ions into cardiac and vascular smooth muscle cells, leading to various beneficial effects.

By reducing the influx of calcium, calcium channel blockers cause both vasodilation of the coronary arteries and peripheral blood vessels. This vasodilation decreases vascular resistance, allowing for improved blood flow to the myocardial tissues without increasing oxygen demand.

Moreover, calcium channel blockers reduce the force of myocardial contraction, leading to decreased myocardial oxygen consumption. The reduction in heart rate further contributes to a decrease in overall workload on the heart, which is particularly advantageous for patients experiencing angina.

Through these mechanisms, calcium channel blockers effectively alleviate the symptoms of angina by improving myocardial oxygen supply while decreasing the demand, thereby providing relief from chest pain during periods of ischemic stress.