DSAE STEMI Review, Module 1: Wavefront Depolarization of the Left Ventricle

Schematic of the wavefront depolarization of the Left Ventricle

Wavefront Direction — Endocardium to Epicardium

Note : These images, illustrations #2, #3, #4, #5, will serve as the building blocks as we predict the waveshape of the 12-lead ECG. This will be accomplished by focusing on one lead at a time and applying the principles of #2, #3, #4, and #5 to that lead.

Illustration #5 demonstrates positive or negative deflection on cardiogram depending on the following three scenarios:

1. Positive deflection if depolarization wave moving toward the electrode to line of sight.

2. Negative deflection if depolarization wave moving away from the electrode to line of sight.

3. No deflection if depolarization wave is perpendicular to line of sight.

DEFINITION: A VECTOR is an entity characterized by both Magnitude and Direction.  It is often denoted with an arrow; direction is indicated by the arrow head.  Magnitude indicated by length of arrow.

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