Pain due to dynamic coronary narrowing from arterial spasm, although ischemic, tends to occur at rest or nocturnally. Myocardial ischemic pain usually lasts only minutes. Pericardial pain, which is due to inflammation involving the parietal pericardium, feels like stabbing, burning, or cutting and is made worse by coughing, swallowing, deep breathing, or lying down. It is less variable in character, position, and referral area than myocardial ischemic pain. It is diminished by leaning forward and remaining still.
Pericardial pain can last for hours or days.
It is not relieved by nitroglycerin. Atypical chest pain tends to be stabbing or burning and is often quite variable in position and intensity from one episode to another. It tends to be unrelated to physical exertion and unresponsive to nitroglycerin. Some persons with atypical chest pain have physical signs or echocardiographic evidence of mitral valve prolapse. Whether the pain is related to the mitral valve prolapse or whether it is an epiphenomenon is controversial because it is common in the absence of evident prolapse.