Sorry but for some reason I cannot post in the clinical section so..

Calcium channel blockers such as Diltiazem block "L type calcium channels" but not "T type calcium channels".

The "T type channels" are found in the SA node and AV node and are responsible for phase 0 (upstroke) of the action potential in that tissue. The "L type channels" are located in the ventricular tissue and are responsible for phase 2 (plateau) of the action potential.

I know that calcium channel blockers produce vasodilation and reduce the heart rate/contractility/conduction velocity. With that being said, I'm having a helluva time understanding WHY it causes a reduction in heart rate being that only "L type channels" are blocked. In my mind I understand the rest of the effects but I would think they would have to block "T type channels" to effect heart rate. Maybe I'm just overthinking it and I should just go with the common thinking of "IT JUST DOES, SO GO WITH IT" but it is bothering the crap out of me.

Please help me!