Gario
Forum Junior
Topics: 14
Posts: 35
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I found an explanation on the internet. (below)
Could anyone provide a more detailed and exact description?
"Why is the T wave upright? This seems odd, given that repolarization is a process of opposite sign to depolarization. The explanation is that the myocytes repolarize in roughly the reverse order to that in which they depolarized. In other words, the last myocytes to depolarize, namely the epicardium and the posterior base of the left ventricle, are the first to repolarize. This is because the myocytes in the epicardium and base have shorter action potentials than those in the endocardium and apex, due to differences in their K+ channel populations. Repolarization begins in the epicardium and base, and spreads towards the endocardium, whereas depolarization does the reverse. As a result, the same polarity develops transiently across the heart during depolarization and repolarization. This is why the T wave is upright."
(Levick, JR An Introduction to Cardiovascular Physiology)
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| brownstone
Forum Newbie
Topics: 3
Posts: 23
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Okay, it took me a while too but i finally found a decent explanation in Thaler's "the only EKG book you'll ever need." You have to think of repolariation as being the opposite of depolarization. Whereas a positive deflection will be seen as a depolarized wave approaches a positive electrode, a replorization will show a positive deflection when moving away from a positive electrode. Repolarization is kinda like a negative depolarization and has to move in a direction opposite to depolarization (otherwise it would just be depolarization), so it turns out to be positive ( a negative of a negative is a positive). Hope that kinda helps...
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| Gario
Forum Junior
Topics: 14
Posts: 35
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Thank you, tirteen13.
Any reply is appreciated.
Gary
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