31. Transmural and subendocardial MI Q-MI does not always correlate with transmural MI Non-Q-MI does not always correlate with subendocardial MI
32.
33. Sampling through electrically “ silent” area into the cavity. In the cavity, all initial wavefronts are directed away Q wave Transmural Injury Q wave
34.
35.
36. Regions of the Myocardium Inferior II, III, aVF Lateral I, AVL, V5-V6 Anterior / Septal V1-V4
Terms transmural and non-transmural MI are appropriate only for pathological studies. Q-MI on ECG do not correspond with transmural MI and non-Q-MI do not correspond with subendocardial MI. That is why we advise to use terms Q-MI and Non-Q-MI to describe ECGs.
Myocardial necrosis consist mainly of electrically inert tissue (loss of electrical potential). Dominant electrical forces will be forces of the opposite wall (directed to the opposite direction) and that is why the overlying electrodes inscribe negative initial deflection (Q wave). If the size of MI is small, reduction of R wave is occur instead of Q wave.
First part of this slide contains the definition of pathological Q wave. However, Q wave is not pathological if it is confined only to lead III or to lead aVL. When the Q wave is inscribed in leads V1 and V2, Q-MI cannot be excluded but many other abnormalities can cause the same pattern.