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1
The Basics
This vector is precisely what our EKG electrodes record when
measuring the electrical flow within the heart. The vector’s angle of
orientation represents the average
direction
of current flow, and its
length represents the voltage (
amplitude
) attained.
At any given moment, the electrical forces moving within the
heart can be represented by a single vector. Furthermore, over
any particular period of time during the cardiac cycle (
e.g.
, atrial
depolarization), these individual vectors can be summed into a
kind of
vector of vectors,
which describes the average direction and
magnitude of current flow during that time period (
e.g.
, during atrial
depolarization, corresponding, let us say, to all the goalie’s kicks over
the first half of the game). Thus, a particular wave (in this case, the
wave of atrial depolarization) can be described by a single vector of
given direction and magnitude. You will see how this works and how
it simplifies our understanding of the 12-lead EKG in the following
section.