Prinzmetal's angina

Prinzmetal’s angina — also known as variant angina or angina inversa — occurs with coronary artery vasospasm resulting in myocardial ischemia. The smooth muscle in the coronary wall contracts without explanation, resulting in decreased blood flow to the myocardium which causes symptoms of angina.

More common in young women, the etiology remains unclear. Symptoms usually occur at rest and are thought to be due to endothelial cell dysfunction. Coronary angiography will show normal coronary arteries (no atherosclerotic stenosis); however, the infusion of ergonovine can reproduce the spam. Ergonovine is not commonly used for this purpose any longer since the spasm can be severe and result in infarction.

Coronary vasospasm can cause ST elevation on the ECG, but only during symptoms. Once the vasospasm resolves, the ECG changes will as well, making it a challenge to diagnose this condition.

The treatment for coronary vasospasm includes dihydropyridine calcium channel blockers (such as amlodipine or nifedipine), alpha blockers and avoiding the use of beta-blockers. Animal studies have shown these to be effective; however, no human trials have been performed. Beta-blockers are thought to cause “unopposed alpha receptor agonism.” Since the beta receptors would be occupied by the beta-blockers, substances (epinephrine, norepinephrine, etc.) can stimulate the alpha receptors more easily, causing worsened vasospasm. Avoidance of alpha agonists are important to treat coronary vasospasm. These include pseudoephedrine and oxymetazoline.