anti-arrhythmia drugs

Question 1

class I B example

Answer 1

lidocaine iv

Question 2

class I B action, indication

Answer 2

Fast binding offset kinetics
No change in phase 0 in normal tissue (no tonic block)
APD slightly decreased (normal tissue)
increase threshold (Na+) decrease phase 0 conduction in fast beating or ischaemic tissue,
ECG; None in normal, in fast beating or ischaemic increase QRS
For : Ventricular tachycardia (esp. during ischaemia)
Not used in atrial arrhythmias or AV junctional arrhythmias

Question 3

class IB

Answer 3

CNS effects: dizziness, drowsiness

GI; Abdominal upset

Question 4

class I C example

Answer 4

flecainide, oral or iv

Question 5

class I C action

Answer 5

very slow binding offset kinetics (>10 s) Substantially decrease phase 0 (Na+) in normal decrease automaticity (increase threshold) 
increase APD (K+) and increase refractory period, esp in rapidly depolarizing atrial tissue.
Effects on ECG increase PR, increaseQRS, increaseQT

Question 6

class I C use

Answer 6

Wide spectrum Used for supraventricular arrhythmias (fibrillation and flutter)
Premature ventricular contractions (caused problems)
Wolff-Parkinson-White syndrome

Question 7

class I C

Answer 7

Pro-arrhythmia and sudden death especially with chronic use (CAST study) and in structural heart disease
increase ventricular response to supraventricular arrhythmias (‘flecainide flutter’)
CNS and gastrointestinal effects like other local anesthetics

Question 8

class II example

Answer 8

bisoprolol,oral metoprolol iv, oral

Question 9

class II action

Answer 9

increase APD and refractory period in AV node to
slow AV conduction velocity
decrease phase 4 depolarization (catecholaminedependent)
Effects on ECG inc PR, dec HR

Question 10

class II use

Answer 10

sinus and catecholamine dependent tachycardia
in atrial flutter or atrial fibrillation
Ectopic beats bisoprolol
Metoprolol for VT

Question 11

class II

Answer 11

bronchospasm
hypotension
don’t use in partial AV block or acute heart failure (are used in stable heart failure)

Question 12

class III example

Answer 12

amiodarone oral, iv

sotalol oral

Question 13

amiodarone action

Answer 13

Effects on ECG
inc PR, inc QRS, incQT, decHR increase refractory period and inc APD (K+)
dec phase 0  and conduction (Na+)
inc threshold
dec phase 4 (β block and Ca++ block)
dec speed of AV conduction

Question 14

amiodarone use

Answer 14

wide spectrum, most arrhythmias

Question 15

amiodarone

Answer 15

Pulmonary fibrosis
Hepatic injury Increase LDL cholesterol
Thyroid disease
Photosensitivity optic neuritis (transient blindness)

Question 16

^ amiodarone

Answer 16

reduce the dose of digoxin and monitor warfarin more closely

Question 17

sotalol action

Answer 17

inc APD and refractory period in atrial and ventricular tissue
Slow phase 4 (β blocker)
Slow AV conduction
ECG effects inc QT, dec HR

Question 18

sotalol use

Answer 18

Wide spectrum: supraventricular and ventricular tachycardia

Question 19

sotalol

Answer 19

Proarrhythmia,

fatigue, insomnia

Question 20

class IV example

Answer 20

verapamil: oral or i.v. diltiazem: oral

Question 21

class IV action

Answer 21

slow conduction through AV (Ca++)
inc refractory period in AV node
inc slope of phase 4 in SA to slow HR
Effects on ECG inc PR, inc/dec HR

Question 22

class IV use

Answer 22

control ventricles during supraventricular tachycardia

convert supraventricular tachycardia (re-entry around AV)

Question 23

class IV

Answer 23

Caution when partial AV block is present. Can get asystoleif β blocker is on board Caution when hypotension, decreased cardiac output or sick sinus
Some gastrointestinal problems (constipation)

Question 24

class V example

Answer 24

adenosine iv,
Digoxin
Atropine
Ivabradine oral

Question 25

adenosine action

Answer 25

natural nucleoside that binds A1 receptors and blocks adenylyl
cyclase thus reducing cAMP which in turn activates K+ currents in AV and SA node causing hyperpolarization → dec HR
leads to dec Ca++ currents - inc refractory period in AV node
Slows AV conduction

Question 26

adenosine use

Answer 26

convert re-entrant supraventricular arrhythmias diagnosis of coronary artery disease (scans)

Question 27

ivabradine oral action

Answer 27

blocks If ion current highly expressed in sinus node
Cardiac effects
slows the sinus node but does not affect blood pressure

Question 28

ivabradine

Answer 28

flashing lights

teratogenicity not known (avoid in pregnancy)

Question 29

ivabradine uses

Answer 29

reduce inappropriate sinus tachycardia
reduce heart rate in heart failure and angina (NICE guidance)
(avoiding blood pressure drops)

Question 30

digoxin action

Answer 30

enhances vagal activity (inc K+ currents, dec Ca++ currents, inc refractory period
slows AV conduction and slows HR

Question 31

digoxin use

Answer 31

treatment to reduce ventricular rates in atrial fibrillation and flutter,

Question 32

atropine action

Answer 32

selective muscarinic antagonist
block vagal activity to
speed AV conduction and increase HR

Question 33

atropine uses

Answer 33

treat vagal bradycardia