Which of the following is a function of calcium blockers?

Calcium blockers, also known as calcium channel antagonists, primarily function by inhibiting the influx of calcium ions through voltage-gated calcium channels in cardiac and smooth muscle cells. By blocking these channels, calcium blockers lead to a decrease in intracellular calcium concentration, which has several physiological effects on the heart and blood vessels.

One of the key effects of calcium blockers is the reduction in heart rate, achieved primarily through their action on the sinoatrial (SA) node, the natural pacemaker of the heart. By decreasing calcium entry into the cells of the SA node, these medications reduce the rate at which the pacemaker generates electrical impulses, resulting in a lower heart rate. This feature is particularly beneficial in managing conditions such as hypertension and certain arrhythmias, where a decreased heart rate can help to alleviate symptoms and reduce cardiac workload.

Understanding this mechanism highlights why decreasing heart beats is an essential and correct function of calcium blockers. In addition to this effect, calcium blockers can also decrease the force of contraction in the heart, which can help in reducing the overall oxygen demand while improving blood flow, but the primary action related to decreasing heart beats distinctly represents their role in heart physiology.