Anti Arrythmics

Question 1

What would you use to prevent ventricular fibrillation and if someone has ventricular tachycardias?

Answer 1

So you would give drugs that act on the ventricular myocytes, these include…

Amiodarone= a K+ channel blocker
Lidocaine= Na+ channel blocker 

Amiodarone is the first choice, however it can not always well tolerated and hence may have to take lidocaine instead.

Question 2

How do beta blockers work, give an example…

Answer 2

Bisoprolol, used in most arrhythmias, it blocks the sympathetic action so it decreases the pacemaker potential slope in the SA node and slows the conduction in the AV node.

Question 3

How would you treat atrial fibrillation?

Answer 3

Rate control to slow AV conduction 
Class 2 or class 4 
Bisoprolol (beta blockers) class 2 
Verapamil (Ca2+ channel blocker- non benzodiazepine)

Question 4

What is adenosine used for?

Answer 4

Used for re entrant arrhythmias in surgery, you get a potassium current activation in the SA node and the AV node.
Restores the sinus rhythm.

Question 5

What is atropine used for?

Answer 5

Vagal bradycardia, as it increases the heart rate.

Question 6

How does digoxin work and when would you used it?

Answer 6

Digoxin works by inhibiting the Na+/K+ ATPase, you get an increase in Na+ and therefore less Na+ moving in via. Na+/Ca2+ transporter, less Ca2+ moving out an therefore an increase in heart rate.

Question 7

What would you use for ectopic beats?

Answer 7

So you would probably use bisoprolol, beta agonists

Question 8

What is used in Angina?

Answer 8

So angina is when there is ischaemia of the myocytes, but without death, therefore you can use a GTN spray which venodilates and lowers the preload (decreasing the workload of the heart).
The nitric oxide activates the guanyl cyclase, which elevated the levels of cGMP and hence reduces the amount of Ca2+ inside, and causes vasodilation!

Question 9

What is the aim of organic nitrates?

Answer 9

Their aim is to reduce the workload of the heart.