Quinidine class IA?

[MudPhud20XX]

Alright so Kaplan pharm says antiarrhythmic drugs slow down heart rythm.

1. Quinidine is an anti-muscarinic which will increase the HR, so would this be an exception?

2. What is the rationale of using quinidine for atrial fibrillation, which is really the problem of having coordinated electrical signals being fired from SA node? I don't think I get this since blocking the activated Na+ channel won't really make the heart beat in a coordinated fashion, right?

Many thanks in advance.

---

Members don't see this ad.

 

[Missorleans]

Nvm

 

[Bertram Lupov]

Alright so Kaplan pharm says antiarrhythmic drugs slow down heart rythm.

1. Quinidine is an anti-muscarinic which will increase the HR, so would this be an exception?

2. What is the rationale of using quinidine for atrial fibrillation, which is really the problem of having coordinated electrical signals being fired from SA node? I don't think I get this since blocking the activated Na+ channel won't really make the heart beat in a coordinated fashion, right?

Many thanks in advance.

1. Quinidine's anti-cholinergic properties antagonizes its anti-arrhythmic effects. It's an imperfect drug.
2. Quinidine may be used to chemically cardiovert out of AF. I think of the quivering atria being the result of numerous re-entrant loops. By decreasing conduction velocity (like dumping ******ant on a fire) and increasing the effective refractory period (like a controlled burn to prevent the further spread of a fire), class IA anti-arrythmics inhibit reentry.

I highly recommend Lilly's Pathophysiology of Heart Disease as a reference text for this topic.

 

[MudPhud20XX]

1. Quinidine's anti-cholinergic properties antagonizes its anti-arrhythmic effects. It's an imperfect drug.
2. Quinidine may be used to chemically cardiovert out of AF. I think of the quivering atria being the result of numerous re-entrant loops. By decreasing conduction velocity (like dumping ******ant on a fire) and increasing the effective refractory period (like a controlled burn to prevent the further spread of a fire), class IA anti-arrythmics inhibit reentry.

I highly recommend Lilly's Pathophysiology of Heart Disease as a reference text for this topic.

Thanks a bunch! Just added that book to my Amazon shopping cart!