MYOCARDIAL INFARCTION

Myocardial infarction (MI) (ie, heart attack) is the irreversible death of heart muscle secondary to prolonged lack of oxygen supply.

Signs and symptoms

Patients with typical MI may have the following symptoms in the days or even weeks preceding the event (although typical STEMI may occur suddenly, without warning):

· Fatigue

· Chest discomfort

· Malaise

Typical chest pain in acute MI has the following characteristics:

· Intense and unremitting for 30-60 minutes

· Substernal, and often radiates up to the neck, shoulder, and jaw, and down the left arm

Laboratory studies

Laboratory tests used in the diagnosis of MI include the following:

· Cardiac biomarkers/enzymes

· Troponin levels: Troponin is a contractile protein that normally is not found in serum; it is released only when myocardial necrosis occurs

· Complete blood cell count

· Comprehensive metabolic panel

· Lipid profile

Electrocardiography

The ECG is the most important tool in the initial evaluation and triage of patients in whom an acute coronary syndrome (ACS), such as MI, is suspected. It is confirmatory of the diagnosis in approximately 80% of cases.

Cardiac imaging

For individuals with highly probable or confirmed acute MI, coronary angiography can be used to definitively diagnose or rule out coronary artery disease.

Levine sign:

References:

https://en.wikipedia.org/wiki/Myocardial_infarction

http://emedicine.medscape.com/article/155919-overview