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Old 06-26-2013
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EKG How QT prolongation can cause Tosades de Points

Hi
How QT prolongation can cause Tosades de Points?
Thanks
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Old 06-26-2013
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Default Another qs

Another question please as I couldn't be able to edit the 1st post,
What is the mechanism of action of Isoproterenol in Torsades de points?
Thanks in advance
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Old 06-26-2013
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Quote:
Originally Posted by melboghdady View Post
Hi
How QT prolongation can cause Tosades de Points?
Thanks
All credit goes to Dr. French guy from the Kaplan videos!

When you speed up the AV conduction (anti muscuranic blockade), this will cause the Ventricles to depolarize sooner. (conduction reaches ventricles faster, so ventricles depolarized earlier)

So on the EKG, the QRS starts sooner. Also, the cell will be maintained in this depolarized state for longer, so that means the T wave will occur much later than normal.

So now you can see why they QRS is prolonged, and corresponding increase in the QT interval. This is called Torsades Rhythm. The EKG will look like only QRS complexes!! and in 50% of cases, the patient will go on to v. fib and potentially death!!! (this is classic of anti muscuarinc drugs)

Last edited by ReggieMiller; 06-26-2013 at 07:56 PM.
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Quote:
Originally Posted by melboghdady View Post
Another question please as I couldn't be able to edit the 1st post,
What is the mechanism of action of Isoproterenol in Torsades de points?
Thanks in advance
problem with prolonged QT interval and Torsades is increased APD. isoproternol can be used to shorten the APD (by increasing the HR)
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Default :)

Thanks doctor for the clear explanation
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Cardiovascular-, EKGs-, Physiology-

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