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Prinzmetal angina, now more commonly called vasospastic angina or variant angina, differs from typical, “classic” angina in several important respects. Its cause is different, its clinical presentation tends to be different, and both its diagnosis and its treatment tend to differ from classic angina.
What Is Prinzmetal angina?
Angina is not always caused by the blockages produced by typical coronary artery disease (CAD). Sometimes angina can occur in people whose coronary arteries are entirely clear of atherosclerotic plaques. In some people, angina can occur because of a sudden spasm in one of the coronary arteries — the arteries that supply blood to your heart.
Prinzmetal angina, or vasospastic angina, is caused by a spasm in a coronary artery.
Coronary artery spasm can produce ischemia (oxygen starvation) in the part of the heart muscle supplied by the affected artery, and angina results. While Prinzmetal angina can have important consequences, including heart attack and life-threatening cardiac arrhythmias, it can almost always be treated very effectively, once it is correctly diagnosed.
Not a Heart Attack, But May Feel Like It
The chest pain that people experience with Prinzmetal angina is indistinguishable from classic, typical angina caused by atherosclerosis. As with typical angina, people with Prinzmetal angina will often describe one or more of several symptoms, including chest tightening, squeezing, pressure, fullness, a weight or knot in the chest, aching, or a burning sensation. Such chest “discomfort” may be accompanied by dyspnea, nausea, or sweating, and/or palpitations. These symptoms often persist for 15 minutes or more. And in contrast to typical angina, which usually occurs during exertion or stress, Prinzmetal angina more typically occurs while at rest. In fact, people most frequently experience Prinzmetal angina at the quietest time of the day —between midnight and early morning.
This combination of symptoms sometimes causes people with Prinzmetal angina to believe they are having a heart attack. In a way, this may not be a bad thing, because people who think they are having a heart attack are more likely to seek medical help. And the sooner Prinzmetal angina is diagnosed, the sooner it can be treated effectively.
Who Gets Prinzmetal Angina?
Prinzmetal angina is more common in women than in men. People with this condition are often relatively young, quite healthy, and commonly have very few risk factors for typical heart disease — with the exception of smoking. Smoking is commonly a major factor in provoking angina in people with this condition because tobacco products can cause arterial spasm. The autonomic nervous system may play a role as well.
Cocaine or amphetamines can also provoke Prinzmetal angina. Substance abusers with Prinzmetal angina are much more likely to suffer permanent (or fatal) heart damage than non-substance abusers who have this condition.
Endothelial dysfunction," a condition in which the inner lining (i.e., the endothelium) of the arteries does not work normally, may be a factor as well, but is not the main cause. Endothelial dysfunction is also associated with cardiac syndrome x, Raynaud's phenomenon, and migraine headaches. And as it turns out, people with Prinzmetal's angina often are also migraine sufferers.
The more severe consequences of Prinzmetal angina are much more likely to occur in smokers, and in people who abuse cocaine or amphetamines.
How Prinzmetal Angina Is Diagnosed
Prinzmetal angina occurs when an 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 electrocardiogram (ECG) shows dramatic elevations of the "ST segment" — the same ECG changes commonly seen with heart attacks. Nitrates usually relieve the spasm very quickly, returning the coronary artery back to normal.
So, the things healthcare providers look for to diagnose Prinzmetal angina are:
- • typical “anginal” chest pain,
- • accompanied by dramatic changes on the ECG,
- • which are relieved by nitrate administration,
- • with “normal’ coronary arteries demonstrated on cardiac catheterization.
In many cases, a healthcare provider will not be present during an actual episode of angina. That is, a person with Prinzmetal angina will come in for evaluation after the angina has gone away. In these instances, diagnostic testing may include ambulatory ECG monitoring for a period of a few weeks (looking for spontaneous episodes of angina accompanied by ECG changes) or stress testing. (While Prinzmetal angina usually occurs at rest, about 20% of people with this condition may have their angina provoked during an exercise test.)
Sometimes, however, a cardiac catheterization with “provocative testing” is necessary to make the diagnosis. Because Prinzmetal angina is caused by coronary artery spasm rather than by a fixed blockage in the artery, the catheterization usually shows “normal” coronary arteries. Further, because Prinzmetal angina is not the only kind of angina that can be seen with normal coronary arteries, making the correct diagnosis may require a demonstration that coronary artery spasm can be provoked.
Two types of drugs, acetylcholine and ergovine, are often used to attempt to induce coronary spasm at the time of heart catheterization. This kind of testing helps find the correct diagnosis.
With the hyperventilation test, the patient is instructed to breathe deeply and rapidly for a full six minutes — which is much more difficult to do than it may sound— while an ECG is being continuously recorded, and echocardiography is done to look for signs of coronary artery spasm. This test is especially useful in people who have frequent episodes of severe Prinzmetal's angina. It tends not to be nearly as useful in those whose episodes are more sporadic, or infrequent.
Testing with acetylcholine or ergonovine is performed during a cardiac catheterization. This kind of testing yields the correct diagnosis more reliably than the hyperventilation test. In this test, one of these drugs is injected intravenously (ergonovine) or directly into a coronary artery (acetylcholine). In people with Prinzmental angina, this often provokes the same localized coronary artery spasm that causes their symptoms. This localized spasm can be visualized during the catheterization procedure. Currently, testing with acetylcholine is considered safer than testing with ergonovine and is the preferred invasive provocative test.
Outlook and Consequences
While in general the outlook of patients with Prinzmental angina is quite good, this condition can trigger dangerous and potentially fatal cardiac arrhythmias. The type of arrhythmia provoked depends upon which coronary artery is involved. For example, if the right coronary artery is involved, it could cause a heart block, and if the left anterior descending artery is involved it might result in ventricular tachycardia.
And while heart attacks are uncommon with Prinzmetal angina, they can occur, producing permanent damage to the heart muscle. Adequate treatment of Prinzmental angina greatly reduces the risk of such complications. In fact, once on effective treatment, people with this condition can expect to lead full, healthy lives.
Treatment
If you have Prinzmetal angina, it will be important for you (as it is with everybody) to control all your cardiac risk factors. But in your case, it is especially critical to avoid tobacco products, which are powerful stimulants of coronary artery spasm.
Calcium channel blockers are often the first line agent used for vasospastic angina. If additional medication is required, a nitrate may be added to a calcium channel blocker.
Also, you might discuss with your healthcare provider the use of a statin — a class of drugs that not only lower cholesterol but also improve endothelial function — as recent data suggests that statins can help to prevent coronary artery spasm.
Drugs that can trigger coronary artery spasm and which you generally ought to avoid include many beta-blockers and some migraine drugs — in particular, Imitrex (sumatriptan). Aspirin should be used with caution as it may exacerbate vasospastic angina.
A Word From Verywell
Prinzmetal angina is an uncommon condition that produces angina due to spasm in a coronary artery. While Prinzmetal angina can sometimes lead to severe consequences (especially in smokers or people who abuse cocaine or amphetamines), it can usually be treated very successfully once the correct diagnosis is made.