[hana]

From Kaplan I learned that class 1C do not change Action Potential duration.
BUT I just read this q in UW which says class 1A, 1C and class 3 all increase QT interval.

Any comments?

 

[patelMD]

Class 1A there is increase of both (QT & AP).

Class 1B there is decreased AP only.

Class 1C there is no effect on AP.

Kaplan is right (FA Agrees), what UW is saying is that AP will not correlate with QT intervals..

 

[hana]

Class 1A there is increase of both (QT & AP).

Class 1B there is decreased AP only.

Class 1C there is no effect on AP.

Kaplan is right (FA Agrees), what UW is saying is that AP will not correlate with QT intervals..

i do not understand how APD do not correlates with QT interval.
what is QT interval exactly? it is ventricular contraction .what does action potential durartion mean? is not QT INTERVAL a part of APD?

 

[patelMD]

i do not understand how APD do not correlates with QT interval.
what is QT interval exactly? it is ventricular contraction .what does action potential durartion mean? is not QT INTERVAL a part of APD?

When its not alike / part of it.. then its called an arrhythmia! You got it

 

[im99]

QT interval means ventricular refractoriness. i think it corresponds to ERP ( effective refractory period) and action potion duration is 'approximately' equal to ERP..
APD= ERP+ RRP

I hope i am right...