How is mechanism of action of Ca channel blockers?

CCB prevent the entry of Ca to myocytes (smooth muscles mainly) through the L type Ca channels by binding on the a1 site, this leads to less actin-myosin interaction thus relaxation of different types of smooth muscles causing vasodilation, in addition to blocking of myocardial contractility, decreased HR and decreased velocity of conduction w/in heart (negative ionotropy, chronotropy, and dromotropy)