thaler chapter 1

Making Waves

35

As the wave of depolarization recedes, a negative deflection is inscribed.

EKG

The wave of depolarization begins to recede from the electrode, gener- ating a negative deflection.

The EKG finally returns to baseline once again when depolarization is complete.

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EKG

The cell is fully depolarized, and the EKG once again returns to baseline.

The final inscription of a depolarizing wave moving perpendicularly to a positive electrode is therefore a biphasic wave .

What would the tracing look like if the recording electrode were placed over a region of pacemaker cells sufficient to generate a detectable current? The tracing would show a downward, negative deflection, since all the current is moving away from the origin where you are recording.