The Hip: Preservation, Replacement and Revision

Myocardial Infarction on EKG



- See: EKG interpretation

          Presence of Q wave    Reciprocal ST
Location:  or ST seg changes     Depression           Sequelae
------------------
Anterior:  V1-V4 (& poor R wave  II, III, AVF     Ant Hemiblock +/-R.BBB
          progression in V1-V6
Lateral:   I, AVL, V5, V6        V1 - V3                 R.A.D.
Inferior:  II, III, AVF (V6)     I, AVL,V1-3 (V4);  Post HemiBlock
                                                   Rt. BBB
                                                   AV block
Posterior: Abnormally tall R     V1 to V3;
          and T in V1 to V3;

Subendo:   No abnormal Q wave    None:
                  ST seg depression
                  in Ant leads (I, AVL,
                  V1-V6) or inferior
                 leads (II, III, AVL);
Septal:    V1 involvement;
Anterolat: V3-6, aVL, I;

- Discussion of  EKG Changes with MI:
    - ST depression: subendocardial ischemia;
    - ST Elevation : Transmural Ischemia, Acute Injury Phase (along with tall positive hyperacute T waves);
    - T Inversion  : Over days to weeks after MI, deep T wave inversion replaces ST seg elevation;
    - Q wave: Occur 24-48 hrs after a transmural MI; A Q wave is the initial negative deflection of QRS complex;
           A "significant" Q wave is 0.04 sec in duration and >25% Ht of R wave;
           - note: Q waves cannot be diagnosed w/ Left B.B.B. and old Q waves may mask new Q waves;
    - note: leads I, II, V5, and V6 commonly contain insignificant Q waves; ignore Q wave in AVR



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, December 19, 2011 4:03 pm