Acute myocardial infarction is a sudden heart attack that occurs without warning. Often, the pain cannot be diagnosed in the field. This is because there is often no history of prior angina or any history suggesting heart disease. These patients may have an embolism that caused the attack.
Such patients need a thorough workup to ensure they do not have any hypercoaguable states or causes of thrombus in the body, if found, such a cause needs immediate treatment to prevent future emboli. During such an attack, the thrombus dislodges from its sight of formation and attaches to the heart vessels, blocking the supply.