MI Diagnosis

Page by: E.J. Mayeaux, Jr., M.D.
Louisiana State University Medical Center Shreveport, Louisiana

      l           Cardiac Enzymes in MI

LDH  -l        *                 +

      l      * : *           +   :   +

 or  -l     *  :   *     +       :       +

      l    *   :     *+          :           +

CPK  -l   *    :      *          :            +

      l  *     :  +     *        :             +

     -l--+--+--+--+--+--+--+--+--+--+--+--+-//-+-

        .5  1     2     3     4     5     6   7-14

                         Days



Enzyme : Onset : Peak : End : False Positive

CPK    :  <1   : 1-2  : 2-4 : Muscle, Brain Ds.

AST    :   1   : 1-2  : 3-4 : Muscle, Brain Ds.

LDH    :   2   : 4-5  : 7-14: Lung embolus, renal infarct, hemolysis

Risk Factors for MI

• Major:
• • • Increased Cholesterol
    • • Serum > 200
      • HDL < 35
      • LDL > 120
    • Hypertension
    • Smoking
    • Family History of MI
    • Diabetes Mellitus
  • Minor:
  • • Obesity
    • Sedentary Lifestyle

  ---

  Must DDx from Pericarditis

  • Pleural/ Pericardial Pain
  • Friction Rub
  • Diffuse ST changes in multiple leads.
  • Lack of Q Waves
  • Lack of rise of enzymes

  ---

  Causes of ECG ST Segment Elevation

  • Acute myocardial infarction (Restricted to one coronary territory)
  • Coronary spasm (Reversible ST elevation, especially after nitroglycerin or calcium antagonist)
  • Pericarditis (Diffuse; associated P-R depression)
  • Left ventricular aneurysm (Associated Q waves)

  ---

  Return to The Intern in the Middle of the Night Home Page

  Return to LSUHSC-S Family Medicine Home Page

  Return to the LSUHSC-S Home Page.