9.1: Cardiac Arrthymia Drugs Flashcards Preview

Semester 5 > 9.1: Cardiac Arrthymia Drugs > Flashcards

Flashcards in 9.1: Cardiac Arrthymia Drugs Deck (13):
1

In cardiac myocytes, which ion has its highest concentration inside the cells?

K+

2

What happens in each phase of a fast cardiac action potential?

As VGSCs open, Na floods in make the cell positive
K+ starts to leave but Ca2+ also enters resulting in a plateau phase
K+ leaves and the membrane is hyperpolarised

3

What type of drugs are class 2 anti arrhythmic drugs?

Beta blockers

4

What arrhythmia can amiodarone predispose to?

Torsades de pointes
(Due to QTc prolongation)

5

What can atropine be used for?

Bradycardia

6

When is digoxin mainly used?

In atrial fibrillation, atrial flutter, heart failure

7

How does digoxin work?

Cardiac glycoside
Inhibits Na/K-ATPase
So intracellular Na accumulates
This inactivated NCX
So intracellular Ca2+ accumulates
This lengthens the cardiac action potential and increases the contractility

8

What are some precautions with digoxin?

Renally excreted, so CI in renal failure
Narrow TI, can cause hyperkalaemia, so cardiac monitoring necesssary

9

How is adenosine administered?

Rapid IV bolus with a half life of seconds

10

What carrythmias can amiodarone be used for?

Many, widespread
Especially ventricular

11

What are some side effects of amiodarone?

Lots of serious ones
Nausea
Vomiting
Tremor
Photosensitivity
Pulmonary fibrosis
Constipation
Hepatic injury
Optic neuritis

12

What is the action of class 1 anti arrhythmics?

Na channel blockers
(E.g. lidocaine, flecainide)

13

How does amiodarone work?

K+ channel blocker
Prolongs phase 3 of the AP (as less permeability to K+)