Arrhythmia

Question 1

Class IB

Answer 1

Na channel blockers e.g. Lidocaine

Question 2

Lidocaine MoA

Answer 2

Block fast Na channels resposible for phase 0 (decrease slope)
Ventricular myocytes
No effect on SAN/AVN
rapidly depolarizing tissue- particularly post MI damage

Question 3

Lidocaine use

Answer 3

Ventricular tachycardia (ventricular myocyte selective)

Question 4

Class IC

Answer 4

Flecanide

Question 5

Flecainide MoA

Answer 5

Stronger decrease phase 0 than Lidocaine
decreases automaticity
increases action potential duration

Question 6

Flecainide use

Answer 6

Wide spectrum

Question 7

Flecainide ADR

Answer 7

Pro-arrythmic - give B blocker to prevent ventricular tachycardia

Question 8

Class II

Answer 8

B blockers e.g. bisoprolol

Question 9

B blocker MoA

Answer 9

B1 receptor- SAN/AVN
decrease sinus rate, conduction velocity
decrease phase 4 (upstroke of pacemaker)

Question 10

B blocker ECG effect

Answer 10

Increase PR

decrease HR

Question 11

B blocker uses

Answer 11

Catecholamine dependent tachycardia (SNS)
AVN re-entry arrhtyhmias
Afib

Question 12

B blocker ADR

Answer 12

Bronchospasm

Hypotension

Question 13

B blocker warnings

Answer 13

AV block

Question 14

Class III

Answer 14

K channel blockers

E.g. Amiodarone

Question 15

Amiodarone MoA

Answer 15

Increase refractory period and AP duration
decrease phase 0
decrease phase 4 (B block and Ca block)
decrease AV conduction

Question 16

Amiodarone ECG effects

Answer 16

Increase PR, QRS, QT

decrease HR

Question 17

Amiodarone ADR

Answer 17

Pulmonary fibrosis
increase LDL
optic neuritis

Question 18

Amiodarone DDI CYPs

Answer 18

Inhibits CYP2C9, CYP34A (warfarin)

Question 19

Amiodarone warnings

Answer 19

Thyroid disease- contains iodine.

Question 20

Sotalol MoA

Answer 20

Class II and III effects
Increase APD and refractory period
Slows phase 4
Slows AV conduction

Question 21

Class IV

Answer 21

Ca channel blockers e.g. Verapamil

Question 22

Verapamil MoA

Answer 22

Ca channel underlies upstroke in pacemaker cells.
slows AV conduction
increases refractory period in AVN
Increase phase 4 slope SAN

Question 23

Verapamil uses

Answer 23

Surpaventricular tachycardia

Re-entry around AV

Question 24

Verapamil DDI

Answer 24

B blocker- asystole

Question 25

Adenosine MoA

Answer 25

Binds to A1 receptor decrease CAMP --> increase K channels --> hyperpolarisation --> decrease HR slows AVN conduction

Question 26

Adenosine uses

Answer 26

supraventricular arrhythmia - EMERGENCY | diagnosis of coronary artery disease

Question 27

Ivabradine MoA

Answer 27

Blocks funny current in SAN- decreases HR

Question 28

Ivabradine uses

Answer 28

Heart failure | Sinus tachycardia

Question 29

Digoxin MoA

Answer 29

Inhibits Na/K ATPase Decrease HR Increase contractility

Question 30

Digoxin uses

Answer 30

Atrial fibrillation and flutter

Question 31

Atropine MoA

Answer 31

Selective mAChR antagonist (M2 in the heart) blocks vagal activity Increases HR and AV conduction

Question 32

Atropine uses

Answer 32

Bradycardia