Stable angina has a typical pattern. You can likely predict when it will happen. It happens
when your heart is working harder and needs more oxygen, such as during exercise. Symptoms go
away when you rest or take nitroglycerin.
Unstable angina is a change in your usual pattern of
stable angina. It is a warning sign that a heart attack may soon occur. It is an
Some people don't have any symptoms. This is called "silent ischemia." In rare cases, you can even have a "silent heart attack," a heart attack without symptoms.