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QRS Complex and T Wave of ECG/EKG

Hello,

Firstly, I want to know where the individual waves of the QRS complex come from.

And why does the depolarization curve go down, when—looking at an individual action potential—the part of the line moving down represents repolarization? Why does repolarization have its own spike, and why is it positive on the y axis (mV), instead of negative?

Also, I’m having trouble understanding the height of the T wave. I understand that the depolarization of the smaller atria will produce a smaller (P) wave compared to the QRS complex, where the larger, more muscular ventricles depolarize. What I do not understand is why the T wave, which represents ventricular repolarization, is so small in vertical length as compared to the QRS complex.

When you look at each individual action potential, repolarization reestablishes the original membrane potential when at rest; meaning the section of the curve representing repolarization has the same height as the part of the curve representing depolarization.

Why, then, is the QRS complex so tall and the T wave so short? And shouldn’t the T point downward instead of upward (as I had mentioned earlier)?

Thanks.

(edited 9 years ago)

Reply 1

velocitous

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