Angina or heart attack:
how symptoms may differ

Article written and reviewed by Dr Luca Moretti

Angina and a heart attack can cause very similar symptoms, and there is no safe way to distinguish them at home based only on the type of pain. An episode of stable angina tends to occur in fairly predictable circumstances, for example during exertion or emotional stress, and often improves within a few minutes after stopping the activity or following already prescribed treatment. A heart attack, by contrast, may cause new, more intense, or prolonged pain, occur at rest, and be associated with shortness of breath, sweating, nausea, or weakness.
These differences can provide clues, but they cannot rule out a heart attack. Unstable angina can also occur at rest or with new and prolonged pain, and heart attack symptoms may be relatively mild. If the clinical picture is new, different from usual, or suspicious, the priority is not to determine on your own which of the two conditions is present, but to seek medical assistance promptly.

In practice, particular attention should be paid to:

• chest pain that occurs for the first time or differs from usual episodes;
• pain that occurs at rest or with progressively less exertion;
• an episode that is more intense, more frequent, or longer than usual;
• chest pain or discomfort lasting more than 15 minutes or recurring within one hour;
• shortness of breath, sweating, nausea, weakness, dizziness, or a feeling of fainting;
• pain extending to one or both arms, shoulders, back, neck, or jaw.

Stable angina and myocardial infarction belong to the spectrum of ischemic heart disease, but they describe different situations. In angina, ischemia is transient and does not necessarily involve myocardial necrosis; in myocardial infarction, acute myocardial injury with necrosis occurs. This guide focuses on what a person can observe in symptoms and, above all, on the limitations of those observations.

When the clinical picture is more consistent with stable angina

In the most classic pattern, stable angina causes discomfort in the center of the chest during activities that increase cardiac workload, such as walking quickly, going uphill, or exerting oneself. It may also occur with emotional stress, cold exposure, or after large meals. The symptom is often described as pressure, heaviness, tightness, burning, or squeezing and may extend to the arms, shoulders, neck, jaw, or back.
What suggests a stable situation is not a single characteristic of the pain, but the reproducibility of the pattern: the same type of symptom tends to occur at a similar level of activity and resolve within a few minutes when exertion stops or after prescribed antianginal therapy. Even this pattern, however, is not perfect. More recent guidelines emphasize that many people with coronary artery disease do not display all the features traditionally considered "typical" and that exertional dyspnea or less easily recognized symptoms may predominate.

For this reason, pain should not be considered harmless simply because it does not match the classic description of angina. In addition, the perceived severity of the symptom does not directly measure the severity of coronary artery disease: very severe pain does not necessarily mean a more severe stenosis and, conversely, significant disease may produce modest symptoms.

When pain may indicate an acute coronary syndrome

The most important warning sign is a change from the person's usual pattern. Pain that occurs for the first time, develops at rest, becomes more frequent, lasts longer, or is triggered by progressively less exertion may indicate an acute condition. This includes both unstable angina and myocardial infarction.
European guidelines consider prolonged chest pain particularly alarming, especially if it lasts more than 15 minutes, or pain that recurs within about one hour. This is not, however, a threshold to wait for before seeking help: new and strongly suspicious pain associated, for example, with dyspnea, sweating, nausea, marked weakness, or a feeling of fainting requires urgent assessment even if it started more recently.

A heart attack does not necessarily cause unbearable pain. It may present with moderate pressure, discomfort resembling indigestion, or mainly with shortness of breath, nausea, or weakness. Likewise, the fact that pain decreases spontaneously does not prove that the problem has resolved: ischemia can be intermittent and symptoms may ease and then recur.

Why symptoms alone cannot determine with certainty whether it is a heart attack

Unstable angina and myocardial infarction are part of the acute coronary syndromes and may be practically indistinguishable at onset. The fundamental difference is that myocardial infarction involves acute injury to myocardial cells, whereas in unstable angina ischemia does not cause necrosis detectable by the diagnostic criteria for myocardial infarction.
Determining this requires clinical assessment, an electrocardiogram, and measurement of high-sensitivity cardiac troponin. In some situations, serial troponin measurements and additional tests are required. For this reason, a normal external appearance, pain that is not very severe, or an inconclusive first test should not be used by the person to self-diagnose.

The response to nitroglycerin does not resolve the uncertainty either. Nitroglycerin may reduce ischemic pain, but symptom improvement is not a reliable diagnostic test and cannot establish that a heart attack is not occurring. People who have nitroglycerin because it was prescribed for a known diagnosis should follow the plan agreed with their physician, without using the medication as a test to decide whether or not to seek assistance.

What to do if you already have a diagnosis of angina

People with stable angina often learn to recognize their usual pattern: which activity triggers the symptom, how it presents, and how quickly it tends to resolve. If an episode is identical to those already assessed by the cardiologist, exertion should be stopped and the individual's prescribed treatment instructions followed. It is not prudent, however, to change doses or medications independently based only on the symptom.
The situation changes when angina no longer behaves as usual. Pain that is more frequent, longer, more intense, triggered by less activity, or occurring at rest should be regarded as a new problem until it has been assessed. The same applies if additional symptoms develop, such as marked shortness of breath, cold sweating, nausea, loss of consciousness, or severe weakness.

If chest pain or discomfort is new or suspicious, lasts a long time, or recurs within a short period, you should call 112 or 118. It is preferable not to drive yourself to the emergency department. When the uncertainty is between unstable angina and myocardial infarction, the correct place to resolve it is an emergency pathway with ECG and biomarkers, not observation of symptoms at home. For a specific overview of heart attack warning signs, see also the guide on heart attack symptoms.

Frequently asked questions about angina and heart attack

How can you tell whether it is angina or a heart attack?
They cannot be distinguished with certainty from symptoms alone. A predictable exertional episode that resolves quickly may be more compatible with stable angina; pain that is new, occurs at rest, is prolonged, or differs from usual is more concerning. Diagnosis requires medical assessment, ECG, and troponin testing.
Can angina also occur at rest?
Yes. This may occur in unstable angina and in other forms, such as vasospastic angina. New or unexpected pain at rest warrants urgent assessment because it may fall within an acute coronary syndrome.
If the pain improves with nitroglycerin, does that mean it is not a heart attack?
No. Relief after nitroglycerin does not rule out a heart attack and should not be used as a diagnostic test.

How long can angina pain last?
In stable angina it often lasts a few minutes and tends to resolve when exertion stops or with prescribed treatment. Duration, however, is not sufficient to make a diagnosis.
When should you call 112 or 118?
When pain is new, severe, occurs at rest, is prolonged, recurs within a short period, or is associated with shortness of breath, sweating, nausea, weakness, fainting, or radiating pain. Pain lasting more than 15 minutes or recurring within one hour is particularly alarming.