Calcium channel blockers, also known as calcium antagonists, are a kind of drugs that can selectively block Ca2+ from flowing into cells through voltage-dependent calcium channels and reduce the intracellular Ca2+ concentration. Commonly used calcium channel blockers in clinic mainly include aniline (such as verapamil), dihydropyridine (such as nifedipine) and diltiazem (such as diltiazem). Verapamil was the first calcium channel blocker discovered. In 1967, Fleckenstein of Germany found that the effect of verapamil on the heart was similar to that after removing Ca2+ from the solution, which could reduce the contractility of the heart without affecting the change and amplitude of membrane potential, so it was called calcium antagonist. Since then, calcium channel blockers have been widely used in clinic.