Definition:

Myocardial infarction (a.k.a. "heart attack") is a severe condition where the muscular layer of the heart (myocardium) is deprived of its blood supply and oxygen for a extended period of time.  Causes of this deprivation include thrombus/clot occluding a blood vessel in the heart or vessel spasm (seen in cocaine users).

Symptoms:

• Severe, "pressure-like" chest pain that lasts more than 30min and not relieved by nitroglycerin
• Pain can radiate to jaw, shoulder, left arm, neck
• Nausea/vomiting
• Diaphoresis (sweating)
• Dyspnea (shortness of breath)

Diagnosis:

• Physical exam - may have low blood pressure or high heart rate, new mitral regurgitation murmur
• Electrocardiography - look for ST segment elevations/depressions or T-wave inversions
• Cardiac enzyme studies - can trend out to see if heart muscle was destroyed

Treatment:

• Nitroglycerin for pain relief
• Morphine sulfate for pain relief and anxiety
• Thrombolysis (streptokinase, t-PA) given within 6hrs of chest pain onset
• Antiarrhythmic therapy
• Digitalis/vasodilators for treatment of heart failure
• Adjunctive therapy - beta-blockers, ACE inhibitors, anticoagulants, aspirin