What distinguishes dihydropyridine calcium channel blockers from non-dihydropyridine calcium channel blockers?

Dihydropyridine calcium channel blockers are primarily distinguished by their predominant influence on vascular smooth muscle rather than cardiac muscle. These agents mainly cause vasodilation by inhibiting calcium entry into vascular smooth muscle cells, which leads to a reduction in peripheral vascular resistance and a decrease in blood pressure. This effect is mainly why they are frequently used in the management of hypertension.

In contrast, non-dihydropyridine calcium channel blockers, such as verapamil and diltiazem, have a more significant impact on the heart. They slow down the conduction through the AV node and reduce heart rate and contractility, which makes them useful in treating cardiac conditions like atrial fibrillation as well as hypertension.

While other options mention effects on heart rate or rapid action, those characteristics do not define the fundamental difference in their primary sites of action. The correct understanding of the specific location and mechanism of action is crucial for the appropriate clinical application of these medication classes in treating cardiovascular diseases.