Action potential duration and the QT interval
please help me get these
i need to know ;
1-what factors determine QT interval? how come sometimes medications which widen QRS do not change QT interval? is not QRS complex a part of QT?
2-all class1 antiarrytmics block sodium channels at phase 0,then should not we expect all class1s widen QRS? then why i just read class1a and 1c,but not 1B widen qrs?and again we have long QT with class1A but not with 1c,how come?
3-again about QRS, how come we have widen qrs in ventricular tachycardias??? i mean how ventricel could contract fast if it spends more time during depolarization?
2-is QT same as action potential duration(APD)?
i do not feel good to ask these very basic q about heart physiology that i was supposed to know well before ,,yearsssss back, but i have to understand it sometime , better now!
thankss for any inputs
i need to know ;
1-what factors determine QT interval? how come sometimes medications which widen QRS do not change QT interval? is not QRS complex a part of QT?
2-all class1 antiarrytmics block sodium channels at phase 0,then should not we expect all class1s widen QRS? then why i just read class1a and 1c,but not 1B widen qrs?and again we have long QT with class1A but not with 1c,how come?
3-again about QRS, how come we have widen qrs in ventricular tachycardias??? i mean how ventricel could contract fast if it spends more time during depolarization?
2-is QT same as action potential duration(APD)?
i do not feel good to ask these very basic q about heart physiology that i was supposed to know well before ,,yearsssss back, but i have to understand it sometime , better now!thankss for any inputs
