12.02.4 Atypical Angina

Atypical angina is due to coronary artery spasm. The spasm closes the blood vessel, and gives the same symptoms as typical angina. As contraction of vascular smooth muscle requires Ca^{2 +} entry into cells through Ca²⁺ channels, Ca²⁺ channel blockers, which act predominantly on the blood vessels (e.g. amlodopine) are effective in atypical angina.