Bradycardia and Tachycardia

Question 1

physiological causes of bradycardia

Answer 1

increased vagal tone, trained athletes

Question 2

non-cardiac causes of bradycardia

Answer 2

endocrine disorders, electrolyte imbalance, drugs

Question 3

intrinsic causes of bradycardia

Answer 3

degeneration of the SAN, the atrium and AVN. These can include sick sinus syndrome or AV blockade or heart block

Question 4

what is sick sinus syndrome

Answer 4

malfunction of the SAN

Question 5

3 degrees of AV blockade/heart block

Answer 5

1. slower AV conduction
2. missed beat to ventricle
3. no conduction to ventricles

Question 6

2 drugs to treat AV blockade:

Answer 6

atropine (antagonizes the muscarine-like actions of acetylcholine, causing a more sympathetic reaction. increasing HR) or isoprenaline (non-selective β adrenoreceptor agonist)

Question 7

class 1 anti-arrhythmic

Answer 7

Na+ channel blockers, slow down AP conduction

Question 8

class 1a anti-arrhythmics

Answer 8

disopyramide, procainamide, quinidine

Question 9

dissociation rate of class 1a anti-arrhythmic

Answer 9

intermediate

Question 10

adverse effects of class 1a anti-arrhythmic

Answer 10

ventricular fibrillation, supraventricular or ventricular tachycardia, dizziness, nausea, blurred vision, loss of balance, dilated pupils, photophobia, dry mouth and potentially extreme confusion, deliriant hallucinations, and excitation especially among the elderly

Question 11

class 1b anti-arrhythmics

Answer 11

lidocaine

Question 12

dissociation rate of class 1b anti-arrhythmics

Answer 12

fast

Question 13

adverse effect of class 1b

Answer 13

CNS effects

Question 14

class 1c anti-arrhythmics

Answer 14

flecainide, propafenone

Question 15

dissociation rate of class 1c

Answer 15

slow

Question 16

adverse effect of class 1c

Answer 16

sudden cardiac death in patients with MI

Question 17

what can disopyramide (1a) treat

Answer 17

ventricular tachycardia and paroxysmal supraventricular tachycardia

Question 18

what can lidocaine (1b) treat

Answer 18

ventricular tachycardia

Question 19

what can flecainide (1c) treat

Answer 19

ventricular tachycardia and paroxysmal supraventricular tachycardia

Question 20

what are Class 2 anti-arrhythmics

Answer 20

block cardiac adrenoreceptors (beta blockers)

Question 21

3 examples of class 2 anti-arrhythmics

Answer 21

propranolol, atenolol, esmolol

Question 22

what can class 2 anti-arrhythmics treat

Answer 22

paroxysmal supraventricular tachycardia and atrial fibrillation

Question 23

adverse effects of class 2 anti-arrhythmics

Answer 23

bradycardia, myocardial depression and bronchoconstriction

Question 24

class 3 anti-arrhythmics

Answer 24

block K+ channels in repolarisation phase 3 of the AP, they prolong the AP

Question 25

2 examples of class 3 anti-arrhythmics

Answer 25

amidarone and sotalol (this is a non-selective beta blocker)

Question 26

what does amiodarone do?

Answer 26

blocks Na+ and Ca2+ channels, and decreases the expression of beta1 adrenoreceptors

Question 27

what can class 3 anti-arrhythmics treat

Answer 27

paroxysmal supraventricular tachycardia, atrial fibrillation, atrioventricular nodal re-entry tachycardia and ventricular tachycardia

Question 28

adverse effects of class 3 anti-arrhythmics

Answer 28

arrhythmias

Question 29

class 4 anti-arrhythmics

Answer 29

calcium channel blockers (L-type)

Question 30

2 examples of class 4 anti-arrhythmics

Answer 30

verapamil and diltiazem

Question 31

verapamil

Answer 31

cardiac selective

Question 32

diltiazem

Answer 32

cardiac and vascular selective

Question 33

what can diltiazem treat

Answer 33

paroxysmal supraventricular tachycardia and atrial fibrillation

Question 34

effects of class 4 anti-arrhythmics

Answer 34

bradycardia, reduced myocardial contractility, hypotensiokn

Question 35

the 4 classes of drugs lie under which classifications

Answer 35

Vaughan Williams

Question 36

5 drugs used to treat tachycardia not in the VW classification

Answer 36

adrenaline
atropine (in 2nd/3rd degree AV block)
isoprenaline (in 2nd/3rd degree AV block)
adenosine (paroxysmal supraventricular tachycardia)
digoxin (ventricular fibrillation)