How can diagnosis of chest pain of acute pericarditis than chest pain of acute myocardial infarction?

PAIN OF MYOCARDIAL INFARCTION : it is precipitated on exertion and is relieved on taking rest. History of easy tiredness is also present. When pain starts it is in chest or epigastric region radiating to left arm or jaw.
PAIN OF PERICARDITIS: there is history of some heart problem and it is PRECIPITATED ON BREATHING MOVEMENTS. Usually dont radiates

Differential diagnoses between Pericarditis and Myocardial infarction should not be left to perception of symptoms. You run the risk of mistaking an MI for inflammation and doing yourself real harm. Even if a patient came into the ER with a classic pericardial rub (sounds like two pieces of leather being rubbed together when you listen with a stethescope), I would still get the cardiogram and send off cardiac enzymes (most notably Troponin I) just to document that he wasn't having an MI.

Besides, no one ever said that you can't have both at the same time. Since the symptoms are so close, a prudent practice would be to rule out both.

Ralph