Drugs for Arrhythmias & CVS

Question 1

What happens if you completely block receptors of the heart with propranolol and atropine?

Answer 1

Nothing much. Heart beats on its own.

Question 2

T/F the autonomic system controls the beating of the heart itself.

Answer 2

false. only the rate.

Question 3

SA node depolarizes spontaneously with what ion? What’s the membrane potential?

Answer 3

Ca2+ at ~60mV - +20mV

Question 4

What happens at phase 3 of SA node spontaneous depolarization?

Answer 4

K+ out

Question 5

How does the parasympathetic slow down the SA node?

Answer 5

via ACh –>muscarinic (M2) receptors –>GPCR decrease cAMP = open K+ channels which slows down pre potential threshold.

Question 6

how does sympathetic acceleration of SA node happen?

Answer 6

NA –>B1 adrenoreceptors –>GPCR –>increase cAMP, open Ca2+ channels which increases slope of pre potential threshold

Question 7

What’s a risk of accelerating the SA node?

Answer 7

can trigger dysrhythmias

Question 8

resting membrane of ventricular action potential?

Answer 8

-90mV

Question 9

ventricular action potential depolarization involves which ion?

Answer 9

Na+ in

Question 10

4 Symptoms of dysrhythmias:

Answer 10

SOB, faiting, fatigue, chest pain

Question 11

3 mechanisms of dysrhythmias:

Answer 11

1. altered formation (Nodes)
2. altered conduction (extra beats, or conduction block)
3. triggered activity (excess sympathetic

Question 12

What is conduction block?

Answer 12

ventricles adopt their own slower pace than the nodes

Question 13

4 classes of antidysrhythmics

Answer 13

1. Na+ (mild, mod, strong) (1a, 1b, 1c)
2. B-adrenoceptor antagonist (SA node)
3. K+ blocker, delay phase 3
4. Ca2+ blocker (great for SA AV nodes

Question 14

Na+ blockers reduce slope 0 and peak of SA/AV nodes. T/F?

Answer 14

False. it’s of the ventricular action potential.

Question 15

What’s quinidine? does two things to the action potential graph:

Answer 15

moderate Na+ channel blocker

1. prolong repol
2. increase effective refractory period

Question 16

what’s ERP

Answer 16

effective refractory period

Question 17

what’s flecainide? how does it effect ERP?

Answer 17

strong Na+ channel blocker no effect on ERP

Question 18

what’s lignocaine?does two things to the action potential graph:

Answer 18

mild Na+ channel blocker

1. shorten repol
2. decrease ERP

Question 19

What else does lignocaine do? why is it dangerous as a dysrhythmic?

Answer 19

local anesthetic. small therapeutic window

Question 20

2 ways how B-adrenoreceptor antagonists work?

Answer 20

1. inhibit sympathetic

2. stabilising purkinje fibres

Question 21

K+ channel inhibitors do what to the graph?

Answer 21

prolong the phase 3

Question 22

Long term use of Amiodarone?

Answer 22

pulmonary fibrosis

Question 23

What is Amiodarone

Answer 23

K+ channel inhibitor antidysrhythmic

Question 24

Ca2+ blockers do what 2 things?

Answer 24

slow conduction, increase refractory

Question 25

What's verapamil?

Answer 25

Ca2+ channel blocker for SA/AV nodes

Question 26

BP must be what to be called hypertension?

Answer 26

>140/90 mmHg

Question 27

#1 treatment for hypertension?

Answer 27

lifestyle mods 1. no smoking 2. diet 3. weight 4. stress

Question 28

2 ways body controls BP:

Answer 28

neuronal, hormonal

Question 29

Sympathetic alpha-1 adrenoreceptors do what?

Answer 29

constrict vessels

Question 30

Sympathetic beta-1 adrenoreceptors do what?

Answer 30

increase heart rate

Question 31

5 classes of antihypertensive drugs:

Answer 31

ABCDO 1. angiotensin 2. Beta adrenoreceptor 3. calcium channel blockers 4. diuretic 5. other

Question 32

Renin converts what to what?

Answer 32

Angiotensinogen to angiotensin 1

Question 33

'prils'

Answer 33

ACE inhibitors block ang1 to II

Question 34

Contraindicated for 'prils' and 'sartans'

Answer 34

1. Preg 2. bilat renal stenosis 3. angioneurotic oedema

Question 35

Blocking Ang 1 to 2 does what 4 things:

Answer 35

reduces 1. vascular tone 2. aldosterone production 3. cardiac hypertrophy 4. preent bradykinin breakdown

Question 36

Candesartan and Losartan, which is long and which is short acting

Answer 36

``` Losartan = short, reversible Candesartan = long irreversible ```

Question 37

'sartans' targets what?

Answer 37

angiotension 1 receptors

Question 38

'olols' target what?

Answer 38

B-adrenoreceptors

Question 39

Beta blocker does what two things to cardiac output?

Answer 39

reduce rate and contractility

Question 40

Do beta blockers affect renin release?

Answer 40

Yep. Reduces it.

Question 41

How do you get CNS effects with B-adrenoceptor antagonists?

Answer 41

cause it's lipid soluble

Question 42

B-adrenoceptor antagonists contraindicated in:

Answer 42

Diabetes, asthma, AV block

Question 43

What's diltiazem?

Answer 43

Ca2+ blocker, not as strong as verapamil

Question 44

What are the dihydropyridines?

Answer 44

Ca2+ blockers, Felodipine, Nifedipine both vascular, careful with tachyarrhythmias

Question 45

Thiazide Diuretics do what?

Answer 45

decrease Na and Cl in renal tubes, so more water is excreted, less fluid = less BP and blood volume