pharmacology

Question 1

sympathetic stimulation on cardiac rate and force

Answer 1

through Gs, B1-adrenoceptors > increase SA node action potential frequency ad heart rate
- cardiac muscle hypertrophy

Question 2

parasympathetic stimulation

Answer 2

acetylcholine activate M2 cholinoceptors in nodal cells
Gi protein
may cause arrhythmias

Question 3

valsalva manoeuvre

Answer 3

activates aortic baroreceptors

used in supraventricular tachycardia or aortic stenosis

Question 4

massage of bifurcation of carotid artery

Answer 4

stimulates baroreceptors in the carotid sinus

Question 5

pacemaker potential

Answer 5

modulated by the funny current

• hyperpolarization
• cAMP

Question 6

block of HCN channels

Answer 6

decreases the slope of the pacemaker potential and reduces heart rate

Question 7

Ivabradine

Answer 7

selective blocker of HCN (funny) channels
used to slow heart rate in angina
does not work in AF
acts on SA node

Question 8

b-adrenoceptor agonists

Answer 8

dobutamine, adrenaline and noradrenaline

increase force, rate and cardiac output and O2 consumption

Question 9

b-adrenoceptor antagonists

Answer 9

non-selective (b1 or b2) or cardioselective (b1)
propranolol- non-selective
atenolol, bisoprolol, metoprolol- selective 
- arrhythmias
- angina 
- HF
- Hypertension
side effects: asthma, fatigue, HF

Question 10

non-selective muscarinic ACh antagonist - on the heart

Answer 10

atropine- increase HR, no change in BP, used in severe bradycardia
digoxin- HF

Question 11

Organic nitrates in angina

Answer 11

GTN or ISMN

side effects: headaches, hypotension

Question 12

Calcium channel blockers

Answer 12

block the opening of L-type channels > limiting calcium concentration
reduce conduction through AV node
reduce force of contraction
selective for smooth muscle preferred for hypertension

Question 13

ACE inhibitors

Answer 13

Blocks angiotensin I becoming angiotension II
used in hypertension and heartfailure
lisinopril
good for kidneys in diabetes
bad for kidneys in renal artery stenosis
side effects: cough, angioneurotic oedema

Question 14

two types of CCB

Answer 14

Dihydroperidines- amlodipine

rate limiting calcium antagonists- verapamil, diltiazem

Question 15

ARBs

Answer 15

angiotensin II receptor blockers
eg losartan 
used in hypertension and heart failure 
good for kidneys 
no cough

Question 16

Angiotensin II hormone

Answer 16

constricts blood vessels = increase in BP

stimulates salt and water retension in the body = increase BP

Question 17

Alpha blockers

Answer 17

block alpha adrenoceptors to cause vasodilatation
used in hypertension and prostatic hypertrophy
eg doxazosin
side effect: postural hypotension

Question 18

Mineralocotoid antagonist

Answer 18

block aldosterone receptor
used in heart failure and resistant hypertension
eg spironolactone
side effects: hyperkalaemia, renal impairment

Question 19

anti anginal vasodilators

Answer 19

Nitrates (isosorbide), nicorandil (K ATP channel opener), calcium antagonists (amlodipine)

Question 20

anti anginal slow heart rate drug

Answer 20

beta blockers
calcium antagonists (diltiazem, verapamil), Ivabradine

Question 21

anti anginal drugs- metabolic modulator

Answer 21

ranolazine

Question 22

What is the role of calcium in a normal cardiac action potential

Answer 22

slow influx causes a plateau in the myocardial action potential- prolongs contraction of cardiac myocytes

Question 23

prolong QT segment on ECG

Answer 23

hypocalcaemia

Question 24

what is the role of rapid influx of sodium ions in normal cardiac action potential

Answer 24

depolarisation of the cardiomyocytes

triggered by pacemaker cells within the sinoatrial node

Question 25

what is the role of an efflux of potassium ions in normal cardiac action potential

Answer 25

repolarisation of cardiomyocytes occurs in two steps: Directly after depolarisation, there is a transient period of repolarisation followed by the plateau After this plateau, complete repolarisation occurs as more potassium channels are opened

Question 26

ECG changes due to hypokalemia

Answer 26

U waves- a deflection immediately following T wave small or absent T waves (occasionally inversion) prolong PR interval ST depression long QT

Question 27

Bifid P waves

Answer 27

the p-wave has 2 peaks, found in left atrial enlargement

Question 28

Inverted T-waves

Answer 28

found in myocardial ischaemia

Question 29

Delta waves

Answer 29

slurred upstrokes of the QRS complex, found in Wolff-Parkinson-White syndrome

Question 30

Pathological q-waves

Answer 30

large q-waves, found in current or prior myocardial infarction