text: Blood tests will not show imminent heart attack.  High cholesterol readings put one at risk, but not imminently.  There are symptoms that can foreshadow a heart attack, however.  These are most often bouts of fleeting chest pain or chest pressure associated with some shortness of breath.  They can occur with increased frequency and severity over period of weeks to give one a warning.  On the other hand, many heart attacks are sudden and without warning.  There are stress tests to perform in order to see whether the arteries are blocked and high risk of heart attack exists. Talk to your doctor about these.