When a stable angina attack occurs, remain calm. Typically, the pain will subside with rest, so take a break if you are doing a strenuous activity. Try a relaxation technique if stress is causing the angina attack. Take any medication your doctor has prescribed for an angina attack. This may include nitroglycerin to help relax your heart. If symptoms don’t subside with these measures after 15 minutes, seek emergency medical attention (call 911).