Calcium channel blockers for the treatment of coronary artery spasm: rationale, effects, and nursing responsibilities
Braun, L.T.
Heart and Lung the Journal of Critical Care 12(3): 226-232
1983
ISSN/ISBN: 0147-9563 PMID: 6551368 Document Number: 203959
Coronary artery spasm is recognized as a cause of ischemic heart disease, producing a syndrome of the variant form of angina that occurs at rest. Spasm also may play a role in other types of rest angina (unstable angina) and exertional angina. Calcium is essential for the basic tonus of vascular smooth muscle. The accentuated contraction that occurs in coronary artery spasm is the result of an increase in intracellular calcium ions. Current therapy is aimed at blocking the slow calcium currents that are responsible for electrical activation and contraction of smooth muscle cells. A marked coronary vasodilatation is produced with calcium channel blockers, thus demonstrating effective therapy for coronary artery spasm. A similar effect is achieved by nitrates, and these agents will continue to have a role in the therapy of spasm. Calcium channel blockers produce beneficial effects on myocardial oxygen supply and demand and, therefore, are also useful in the prevention of classic exertional angina caused by fixed obstruction. Verapamil and diltiazem possess electrophysiologic effects and have, in addition, proved useful in the treatment of supraventricular dysrhythmias.