Understanding Prinzmetal's Angina

Prinzmetal's angina, or coronary artery spasm, is a relatively uncommon cause of chest pain. It occurs when a spasm strikes in one of the coronary arteries -- the arteries that supply blood to your heart. While this condition can feel scary, it is often treatable. Vigilant medical care is important, though.

Not a Heart Attack, But May Feel Like It

While it can seem -- and feel -- very similar to a heart attack, Prinzmetal's angina is not the same thing. During an important diagnostic procedure known as cardiac catheterization, which lets doctors visualize your heart's arteries, the arteries typically appear normal -- a sign that it is not a heart attack causing the pain but perhaps Prinzmetal's. This is especially true when the disease affects women. In men, however, Prinzmetal's angina more often occurs in the setting of typical coronary artery disease (CAD) - so men's cardiac catheterizations may not show "normal" coronary arteries.

• Read more about angina with "normal" coronary arteries.

Who Is Affected By It? What Causes It?

Anyone can develop this condition, but it's more common in women. Women who develop Prinzmetal's angina are often relatively young, and commonly have few risk factors for typical heart disease, with the exception of smoking. (Smoking makes arterial spasm more likely in some individuals.)

Prinzmetal's angina can also be seen in people who use cocaine or amphetamines, substances that produce arterial spasm. Substance abusers with coronary artery spasm are more likely to suffer permanent (or fatal) heart damage than non-substance abusers.

In some cases, Prinzmetal's angina is thought to be caused by "endothelial dysfunction," that is, when the inner lining (i.e., the endothelium) of the arteries do not work normally. Endothelial dysfunction is also associated with cardiac syndrome x, Raynaud's phenomenon, and migraine headaches. Indeed, women with Prinzmetal's angina often have a history of migraine headaches.

Symptoms

In Prinzmetal's angina, chest pain - often particularly severe chest pain - is triggered because a small area within one of the major coronary arteries suddenly goes into spasm, temporarily shutting off blood flow to the heart muscle supplied by that artery. During these episodes, the electrocardigram (ECG) shows dramatic elevations of the "ST segment" - the same ECG changes commonly seen with heart attacks. However, because the spasm almost always goes away on its own, it is uncommon (though possible) for an actual heart attack to occur with Prinzmetal's angina.

While Prinzmetal's angina can be triggered by exercise, more often it occurs during periods of rest, most typically in the early morning hours. Also, episodes often appear in clusters.

How Is Prinzmetal's Angina Diagnosed?

Prinzmetal's angina should be suspected any time a person has severe chest pain accompanied by dramatic ECG changes, but a cardiac catheterization shows apparently normal coronary arteries. Once the diagnosis is suspected, the cardiologist usually performs what is called "provocative testing," to show whether coronary artery spasm can be induced. If so, Prinzmetal's angina can be definitively diagnosed. Two types of "provocation" are often used to attempt to induce coronary artery spasm - hyperventilation, and ergonovine.

Hyperventilation testing is usually performed in the early morning (when spasm appears most likely to occur). This testing requires the patient to breath deeply and rapidly for a full six minutes - which is much more difficult than it may sound - using continuous ECG monitoring and echocardiography to look for signs of coronary artery spasm. This test can be quite useful in patients who have frequent episodes of severe Prinzmetal's angina. It tends not to be nearly as useful in those whose episodes are sporadic or infrequent.

The ergonovine test yields the correct diagnosis more frequently than the hyperventilation test. Here, the drug ergonovine is administered intravenously, usually during cardiac catheterization. Ergonivine increases vascular "tone" and causes arteries to constrict. In people with Prinzmental's angina, ergonovine very often provokes the same localized coronary artery spasm that causes their chest pain. This localized spasm can be visualized during the catheterization procedure. Fortunately, ergonovine-induced spasm can be quickly reversed with a drug known as nitroglycerin.

What Are the Consequences of Prinzmetal's Angina

While in general the outlook of patients with Prinzmental's angina is quite good, this condition can cause serious problems. It can trigger dangerous and potentially fatal cardiac arrhythmias, especially ventricular fibrillation. And while heart attacks are uncommon, they can occur - which causes permanent damage to the heart muscle. Adequate treatment of Prinzmental's angina greatly reduces the risk of such complications.

How Is Prinzmetal's Angina Treated?

If you have Prinzmetal's angina, it will be important for you to control all your cardiac risk factors - and it's especially important for you to avoid tobacco products.

It is likely that you and your doctor will be able to gain excellent control over your episodes of angina with nitrates and/or calcium channel blockers. Also, you might discuss with your doctor the use of a statin - a class of drugs tat not only lower cholesterol but also improve endothelial function - as recent data suggests that statins can significantly improve Prinzmetal's angina.

Drugs that can provoke coronary artery spasm and which you generally ought to avoid include many beta blockers, and some migraine drugs - in particular, sumatriptan.