Think of the process of ischemia, injury and infarction as a worsening continuum.
If immediate, aggressive and effective care is not provided, ischemia will worsen (or progress) to injury and ultimately infarction (tissue death)
Ischemia, injury and infarction each impact the cardiac complex in unique ways.
12-Lead Analysis requires we follow these steps of analysis.
- ST segment for presence of deviation
- T wave morphology changes
- Q wave morphology changes
The changes I have been referring to must occur in anatomically contiguous leads. This refers to 2 or more leads “looking” at (viewing) the same part of the heart or numerically consecutive chest leads
- II, III, aVF (2 of the 3 leads must show changes. It does not have to be all three)
- I, aVL can show changes and not effect V5 and V6 to still be clinically significant
- Numerically consecutive chest leads
We always recall that V1 is next to V2, but do not forget that V2 is also contiguous with (next to) V3…if V2 & V3 are showing changes, this is clinically significant too. See the next slide for an illustration.