Anti-arrhythmia Therapy

Question 1

What causes cardiac cells to excite and contract

Answer 1

Na enters = depolarisation
Ca enters = contraction
K leaves = depolarisation

Question 2

What do class 1 drugs do

Answer 2

Block Na channels so slow rate of depolarisation
Block AV node
Stabilise membrane

Question 3

Example of class 1

Answer 3

Fleicanide

Question 4

When is it used and when is it CI and what should you do prior to prescribing

Answer 4

AF / flutter for chemical cardio version
SVT with accessory pathway e.g. WPW
Some ventricular arrhythmia’s

CI
Post MI
Structural heart
HF 
AV block
Flutter

Need to do ECHO to look for structural heart as -ve inotropic

Question 5

What are class 2 drugs and what do they do

Answer 5

BB
Block sympathetic system
Depress depolarisation
Depress SVT and VT

Question 6

When is it 1st line

Answer 6

AF

Question 7

What are class 3 drugs

Answer 7

Amiodarone

Sotalol

Question 8

How do they work

Answer 8

K blocker
Increase AP duration
Prolonged repolarisation

Question 9

When are they used

Answer 9

Difficult to treat arrhythmia

Life threatening VT, VF, AF, flutter

Question 10

What is class 4 drug

Answer 10

CCB

• Verapamil
• Dilitizem

Question 11

How do they work

Answer 11

Depress depolarisation

Question 12

When are they used

Answer 12

Paroxysmal SVT

Control AF and flutter

Question 13

What is digoxin

Answer 13

Cardiac glycoside
Inhibits Na / K pump
Positive inotrope - allows Ca to improve contraction

Question 14

When is digoxin used

Answer 14

Heart failure - improve Sx due to inotropic but not mortality
AF for rate control

Question 15

What must you monitor

Answer 15

U+E - K level

Toxicity

Question 16

When is it commonly used

Answer 16

Elderly for rate control in AF with poor heart

Question 17

Why should you use with caution

Answer 17

Renal excreted so increases in renal failure / AKI which elderly prone too

Question 18

What do you do if this happens

Answer 18

Monitor U+E

Reduce dose

Question 19

What other AA will increase level of digoxin / other factors which increase toxicity

Answer 19

Amiadarone

Other

• Hypokalaemia / Mg
• Hypernatraemia / Ca
• Hypothermia
• Hypothyroid
• Age
• Renal failure
• Acidosis
• MI
• Spirnolactone
• Thiazide

Question 20

What are SE of digoxin

Answer 20

Hyperkalaemia - causing arrhythmia
Gout
Nausea
Anorexia
Confusion
Gynaecomastia

Question 21

What are signs of toxicity

Answer 21

Yellow glow (xanthopsia)
N+V
Confusion
Arrhythmia - AV block / Brady

ECG 
Reverse ST tick
Flattened T wave
Short QT 
Av block
VT / VF

Question 22

What do you do if toxicity

Answer 22

Measure digoxin level 8-12 hours after last dose 
U+E= monitor 
ECG
Give digiband
Correct electrolyte

Question 23

When is amiodarone used

Answer 23

Atrial and ventricular tachycardia

Question 24

What may amiadarone interact with

Answer 24

Digoxin - increases level
p450 inhibitor
Warfarin increased

Question 25

What are SE of amiadarone

Answer 25

``` Thrombophlebitis of central vein Bradycardia Long QT Thyroid dysfunction - hypo and hyper Pulmonary fibrosis Hepatic toxicity - Discontinue if LFT spike >2/3x - Do not start if liver issue - Cirrhosis is rare Pneumonitis Grey / blue pigmentation Optic neuritis Corneal opacification Peripheral neuropathy Photosensitivity ```

Question 26

What do you do prior to starting

Answer 26

U+E, LFT, TFT | CXR

Question 27

What do you monitor every 6 months

Answer 27

TFT and LFT

Question 28

What does adenosine do

Answer 28

Slows conduction through AV node causing transient heart block

Question 29

When is it used

Answer 29

SVT to convert to sinus

Question 30

How do you give

Answer 30

IV | Fast bolus as short bolus through large bore cannula followed by saline flash

Question 31

What does it cause intially

Answer 31

Systole | Warn patients that may feel like death

Question 32

When is it CI

Answer 32

Asthma / COPD due to bronchospasm | HF / Severe hypo / heart block

Question 33

What are SE

Answer 33

Chest pain Spasm FLushing WPW

Question 34

What do you do for all class 3 (amiadaraone and stall) and fliecanide (class 1)

Answer 34

Monitor ECG as risk of QT prolongation