Although the mechanism of vasospasm is not clear, it is thought that a defect in calcium transfer in smooth muscle or sympathetic nervous system responses may cause smooth muscle spasm. As with classic angina, nitroglycerin is usually effective as it dilates coronary arteries. Treatment with calcium channel blockers relaxes smooth muscle, decreasing total peripheral resistance, and reducing cardiac work. Unstable Angina . Unstable angina is often called preinfarction angina due to it's propensity for accelerating to myocardial infarction.
Unstable angina is pain with a changing pattern.
Anginal pain of this type appears more often, is more severe, lasts longer, and may appear while at rest. Usually atherosclerosis is involved, and it is uncertain the role coronary vasospasm plays. Individuals with unstable angina commonly require admission for treatment and stabilization that may require cardiac catheterization, angioplasty, or coronary bypass. Types of Pain . Anginal pain is frequently described as squeezing, suffocating, constricting pain.