Cardio 2

Question 1

what causes atrioventricular junctional tachycardias?

Answer 1

re-entry circuits - two separate pathways for impulse conduction

Question 2

what is the enzyme that breaks down bradykinin?

Answer 2

angiotensin converting enzyme - excess bradykinin (since it’s not being broken down) is the reason why some patients on ACEi get a persistent dry cough

Question 3

explain how ACE inhibitors work

Answer 3

ACE inhibitors inhibit conversion of angiotensin I to angiotensin II in the lungs - this prevents it from acting on the adrenals to increase aldosterone secretion and thus cause water and sodium retention at the kidneys.
angiotensin II is also a vasoconstrictor, so ACEi act as vasodilator, and causes sodium and water excretion - lower blood volume, lowers BP.

Question 4

how do angiotensin receptor blockers produce a similar effect to ACEi? give two examples of ARBs

Answer 4

by blocking angiotensin II receptors, so its actions cannot be exerted.
losartan, candesartan.

Question 5

give 2 examples of ACEis

Answer 5

ramipril, lisinopril

Question 6

why do you get hyperkalaema as a side effect of angiotensin 2 receptor blockers?

Answer 6

ARBs cause a direct effect on aldosterone production in the adrenals - aldosterone works on the distal convoluted tubules of kidney by causing sodium to be reabsorbed in return for potassium excretion - ARBs reverse this transfer, so there’s potassium retention.

Question 7

calcium channel blockers are negatively inotropic and negatively chronotropic, what does this mean?

Answer 7

inotropic - reduces the contraction.

chronotropic - lowers the heart rate.

Question 8

how do calcium channel blockers work? give some examples.

Answer 8

decrease calcium entry into vascular and cardiac cells. intracellular calcium is lower - relaxation and vasodilation of arterial smooth muscle.
reduce myocardial contractility and suppress cardiac conduction, particularly at AV node.
this reduces myocardial oxygen demand - important in angina.

dihydropyridines (amlodipine, nifedipine) - selective for vasculature.
non-dihydropyridines (diltiazem, verapamil)- selective for heart

Question 9

what clotting factors does warfarin work on?

Answer 9

2, 7, 9, 10 by inhibiting vitamin K synthesis - so anticoagulates by inhibiting coagulation factor synthesis

Question 10

statins are given to correct hyperlipidaemia, what enzyme do they act on? name 2 statins.

Answer 10

HMG-CoA reductase - involved in making cholesterol.
so they reduce the cholesterol production in liver and increase clearance of LDL-cholesterol from blood.

simvastatin, atorvastatin, pravastatin.

Question 11

if you have a patient that comes in with unstable angina but tells you he is allergic to aspirin, what is then your first line of treatment after giving GTN?

Answer 11

clopidogrel monotherapy

Question 12

give an example of a short and a long acting nitrate

Answer 12

short - glyceryl trinitrate (GTN).

long - isosorbide mononitrate

Question 13

how do nitrates work to reduce the pain of angina?

Answer 13

converted to NO, which is a vasodilator - relaxation of capaticance vessels reduces cardiac preload + LV filling, which reduces cardiac work and myocardial oxygen demand.

Question 14

give 2 possible side effects of nitrates

Answer 14

flushing, headaches, light headedness, hypotension

Question 15

name 3 beta blockers

Answer 15

bisoprolol, atenolol, propranolol, metoprolol

Question 16

how do beta blockers work to improve symptoms of ischaemic heart disease?

Answer 16

they reduce force of contraction and speed of conduction in the heart via beta 1 receptors - reducing cardiac work and oxygen demand.

Question 17

how do beta blockers work as a treatment for AF?

Answer 17

slow the ventricular rate by prolonging the refractory period at the AV node

Question 18

list the indications for beta blockers

Answer 18

IHD - symptoms and improve prognosis.
chronic heart failure.
AF and other SVTs - reduce rate, maintain sinus rhythm.
hypertension - only if other medicines are insufficient.

Question 19

how do beta blockers work as a treatment for hypertension?

Answer 19

reduce renin secretion from the kidney, which is mediated by beta1 receptors.

Question 20

give some possible SEs of beta blockers

Answer 20

fatigue, cold extremities, headache, nausea, sleep disturbance, ED in men.

Question 21

name an aldosterone antagonist

Answer 21

spironolactone, epleronone

Question 22

what cardiac indication do aldosterone antagonists treat?

Answer 22

chronic heart failure - as an addition to beta blocker and ACEi/ARB

Question 23

how do LMWHs work?

Answer 23

inhibit factor Xa by inhibiting antithrombin

Question 24

how does fondaparinux work?

Answer 24

inhibits factor Xa.

Question 25

how does aspirin work in prevention of thrombosis?

Answer 25

it irreversibly inhibits cyclooxygenase (COX) to reduce production of pro-aggregation factor thromboxane from arachidonic acid - reduces platelet aggregation and risk of arterial occlusion.

Question 26

give some examples of antiplatelet drugs, apart from aspirin

Answer 26

clopidogrel, new oral anticoagulants, glycoprotein IIb/IIIa inhibitors

Question 27

how does clopidogrel work?

Answer 27

prevents platelet aggregation by binding irreversibly to adenosine diphosphate receptors on surface of platelets

• independent of COX pathway, so can be taken with aspirin

Question 28

how do glycoprotein IIb/IIIa inhibitors work?

Answer 28

prevent platelet aggregation by inhibiting the GPIIb/IIIa receptor on platelet surface

Question 29

name 2 fibrinolytic (thrombolysis) drugs

Answer 29

alteplase, streptokinase

Question 30

how do fibrinolytic drugs work?

Answer 30

catalyse the conversion of plasminogen to plasmin which acts to dissolve fibrinous clots and re-canalise occluded vessels.
- allows reperfusion of tissues, preventing/limiting tissue infarction.

Question 31

name a loop diuretic

Answer 31

furosemide, bumetanide

Question 32

give a cardiac indication of loop diuretics

Answer 32

symptomatic treatment of fluid overload in chronic heart failure

Question 33

describe the mechanism of loop diuretics

Answer 33

act on ascending limb of loop of Henle to inhibit the Na/K/2CL cotransporter that transports the ions into the cell - water follows these ions, so they have a potent diuretic effect.

also - cause dilation of capaticance vessels - reduces preload + improves contractile function of the heart.

Question 34

what are potassium sparing diuretics used for? name an example.

Answer 34

used as part of combination therapy, to treat hypokalaemia arising from loop/thiazide diuretic use.

amiloride.

Question 35

how do potassium sparing diuretics work?

Answer 35

weak diuretics.
act on distal convoluted tubules in kidney - inhibit sodium and water reabsorption by acting on epithelial sodium channels - causes potassium retention.

Question 36

give an example of a thiazide/thiazide like diuretic

Answer 36

bendroflumethiazide, indapamide, chlortalidone

Question 37

describe the mechanism of action of thiazide diuretics

Answer 37

inhibit the Na/Cl cotransporter in the distal convoluted tubule of the nephron, preventing reabsorption of sodium and water.
also cause vasodilation.

Question 38

for what cardiac problem might sildenafil be prescribed? what class of drug is this?

Answer 38

primary pulmonary hypertension.

phosphodiesterase type 5 (PDE5) inhibitor

Question 39

how does sildenafil work as a treatment of pulmonary hypertension?

Answer 39

causes arterial vasodilation by increasing cGMP (normally broken down by PDE5).