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The Basics
Electricity and the Heart
Electricity, an innate biologic electricity, is what makes the heart go.
The EKG is nothing more than a recording of the heart’s electrical
activity, and it is through perturbations in the normal electrical
patterns that we are able to diagnose many different cardiac and
noncardiac disorders.
All You Need to Know About Cellular Electrophysiology
in a Few Brief Paragraphs
Cardiac cells, in their resting state, are electrically polarized;
that is, their insides are negatively charged with respect to their
outsides. This electrical polarity is maintained by membrane
pumps that ensure the appropriate distribution of ions (primarily
potassium, sodium, chloride, and calcium) necessary to keep the
insides of these cells relatively electronegative. These ions pass
into and out of the cell through special ion channels in the cell
membrane.
The resting cardiac cell maintains its electrical polarity by means of a
membrane pump. This pump requires a constant supply of energy, and
the gentleman above, were he real rather than a metaphor, would soon
be flat on his back.