Dr Lawson Arrhythmic Functional Classification

Question 1

What does the mnemonic below relate to in terms of cardiac mediation?

• Some
• Block
• Potassium
• Channels

Answer 1

• Some = Sodium channel blockers
• Block = B-blockers
• Potassium = K+ channel blockers
• Channels = Ca2+ channel blockers

Question 2

If a patient has sinus tachycardia and we wont to reduce AV node firing, which of the following drugs would be most effective?

1 - Bisoprolol
2 - Flecainide
3 - Amiodarone
4 - Verapamil

Answer 2

1 - Bisoprolol
- B-blocker

• B1 adrenergic receptors are present on pacemaker and cardiomyocytes

Question 3

B-blockers are indicated for treating sinus tachycardia and reduce AV node firing, essentially reducing HR and correcting tachycardia. Although present on pacemaker and non-pacemaker cells, do beta blockers have a larger effect on pacemaker or non-pacemaker cells?

Answer 3

• pacemaker cells

Question 4

Beta blockers inhibit noradrenaline and adrenaline from binding to B1 adrenergic receptors. This reduces the number of which channels from opening?

1 - Na+ (funny current)
2 - L-type Ca2+
3 - Na+
4 - K+

Answer 4

2 - L-type Ca2+
- reduces Ca2+ being released at end of stage 4 and start of phase 3
- decreases slope on graph
- reduces SA node firing and HR
- reduces conduction through AV node

Question 5

What affect do B-blockers have on non-pacemaker cells?

1 - increased chronotropic affect
2 - increase Ca2+ in cells
3 - negative ionotropic affect
4 - positive ionotropic affect

Answer 5

3 - negative ionotropic affect
- reduce force of contraction and HR

Question 6

If a patient has atrial tachycardia and we wont to reduce atrial arrhythmia, all of the following could work, EXCEPT?

1 - Flecainide,
2 - Bisoprolol
3 - Amiodarone
4 - Amlodipine

Answer 6

4 - Amlodipine = class IV (Ca2+ blocker) BUT works mainly on smooth muscles

1 - Flecainide = class I (Na+ blocker)
2 - Bisoprolol = class II (B-blocker)
3 - Amiodarone = class III (K+)

Question 7

If there is a problem in the AV node, all of the following drugs could be used EXCEPT which one?

1 - Bisoprolol
2 - Verapamil
3 - Diltiazem
4 - Amiodarone
5 - Atenolol
6 - Digoxin
7 - Adenosine

Answer 7

5 - Atenolol

Question 8

If a patient has an issue with the ventricular myocardium, we could use all of the following drugs, EXCEPT which one?

1 - Flecainide
2 - Bisprolol
3 - Diltiazem
4 - Amiodarone

Answer 8

3 - Diltiazem

• Mg+ can also be effective here

Question 9

If we want to inhibit an accessory pathway, which 2 of the following would be best?

1 - Flecainide
2 - Bisprolol
3 - Diltiazem
4 - Amiodarone

Answer 9

1 - Flecainide (class I - Na+)
4 - Amiodarone (class IV - K+)

• such as WPW syndrome

Question 10

Typically, which medication is used to treat ectopic beats (atrial or ventricular), other than doing nothing?

1 - Propranolol
2 - Amiodarone
3 - Bisoprolol
4 - Adenosine

Answer 10

1 - Propranolol (B-blocker)
- given at a low dose

Question 11

Typically when treating ventricular tachycardias, which 2 of the drugs are used clinically?

1 - Propranolol
2 - Amiodarone
3 - Bisoprolol
4 - Adenosine

Answer 11

2 - Amiodarone (Class III - K+)
3 - Bisoprolol (Class II - B-blocker)

Question 12

Typically, clinically which 2 of the following drugs are used to terminate a supraventricular tachycardia?

1 - Verapamil
2 - Amiodarone
3 - Bisoprolol
4 - Adenosine

Answer 12

1 - Verapamil (class IV - Ca2+)
4 - Adenosine (others - mixed effects)

Question 13

Typically, clinically which of the following drugs is used to prevent atrial and Atrioventricular nodal reentry tachycardia (AVNRT)?

1 - Verapamil
2 - Amiodarone
3 - Bisoprolol
4 - Adenosine

Answer 13

3 - Bisoprolol (class II - B blocker)

Question 14

Which 2 of the following drugs are used to try and prevent accessory pathways clinically?

1 - Flecainide
2 - Bisprolol
3 - Diltiazem
4 - Amiodarone

Answer 14

1 - Flecainide (class I - Na+)
4 - Amiodarone (class III - K+)

Question 15

In atrial fibrillation, if we want to slow AF clinically, we can use an AV node blocker. Which of the following drugs are commonly used clinically?

1 - Bisoprolol
2 - Diltiazem
3 - Digoxin
4 - Amiodarone
5 - all of the above

Answer 15

5 - all of the above

• Bisoprolol, Diltiazem and Digoxin all slow HR and have a negative ionotropic effect
• Amiodarone = prolong QT interval and reduce HR

Question 16

In atrial fibrillation, if we want to maintain sinus rhythm, we would use an atrial stabiliser. The following drugs are commonly used clinically, EXCEPT which one?

1 - Bisoprolol
2 - Flecainide
3 - Digoxin
4 - Amiodarone

Answer 16

3 - Digoxin
- can be very toxic
- also increases QT interval that can cause torsade des pointes

Question 17

If a patient has sinus tachycardia, typically, which drug is used?

1 - Bisoprolol
2 - Flecainide
3 - Digoxin
4 - Amiodarone

Answer 17

1 - Bisoprolol
- reduces Ca2+ being released at end of stage 4 and start of phase 3
- decreases slope on graph
- reduces SA node firing and HR
- reduces conduction through AV node

Question 18

If a patient has bradycardia, typically, which drug is used?

1 - Bisoprolol
2 - Flecainide
3 - Atropine
4 - Amiodarone

Answer 18

3 - Atropine