AF

Question 1

T/F AF is rare below 50 yo?

Answer 1

true but becomes more prevalent with increasing age

Question 2

what is af?

Answer 2

Abnormal, disorganised electrical signals fired causing the atria to quiver

Question 3

AF is characterised by rapid and uncoordinated electrical activity in the atria and variable conduction through the AV node, this results in rapid and irregular ventricular contraction. It is often further categorised as

Answer 3

valvular or non valvular

Question 4

‘valvular’ AF being associated with patients with …?

Answer 4

mitrial stenosis or prosthetic heart valves. All other causes are consider to be ‘non-valvular’

Question 5

what are the risk factors for AF

Answer 5

hypertension, atherosclerosis and hyperthyroidism, over 65

Question 6

what are the symptoms of AF

Answer 6

dizziness, palpitations, sob, tiredness

Question 7

true or false AF can be asymptomatic?

Answer 7

true

Question 8

a normal HR should be regular and at rest between

Answer 8

60-100bpm

Question 9

give 2 areas where pulse can be felt to measure HR?

Answer 9

neck
wrist

Question 10

what can be used to assess for the presence of irregular pulse if there is suspicion of AF?

Answer 10

manual pulse palpitation

Question 11

if an irregular pulse is detected by manual palpitation was is done next to confirm the diagnosis?

Answer 11

12 lead ecg

Question 12

what are the 2 approaches of treating af?

Answer 12

rate and rhythm control

Question 13

if at any stage treatment fails to control symptoms, symptoms reoccur after cardioversion, specialist management is required and referral should be made within how many weeks?

Answer 13

4

Question 14

ventricular rate can be controlled with what 2 drug classes?

Answer 14

BB or rate limiting CCB

Question 15

if patients have co existing symptoms associated with acute decompensated HF why should ccb not be used?

Answer 15

-> worsen pulmonary oedema caused by hf

Question 16

what is next after monotherapy does not work

Answer 16

combination therapy with any two of a
beta-blocker,
diltiazem
or digoxin

Question 17

why is digoxin only considered if patients do very little physical excercise?

Answer 17

usually only effective for controlling ventricular rate at rest

Question 18

explain how digoxin works as a cardiac glycoside?

Answer 18

increases force of myocardial contraction and reduces conductivity within av node

Question 19

what is the aim for blood conc of dogoxin in micrograms/L?

Answer 19

1-2

Question 20

what is primary method of excretion for digoxin?

Answer 20

renal - so be aware of dosing

Question 21

why is the effect of digoxin potentiated by both hypokalaemia and hypercalcemia?

Answer 21

directly inhibits the transmembrane Na/K/ATPase exchange pump

Question 22

cardiac adverse effects of digoxin (toxicity)?

Answer 22

ventricular arrhythmias
av block
atrial arrhythmias
sinus bradycardia

Question 23

non cardiac adverse effects of digoxin tox?

Answer 23

nausea/ vomiting
anorexia
abdominal pain
visual disturbances
confusion

Question 24

why are people with af at higher risk of stroke

Answer 24

sluggish blood flow within the fibrillating atria

Question 25

what tool calculates the risk of stroke?

Answer 25

CHA2DS2VASc

Question 26

what tool calculates the risk of bleeding?

Answer 26

ORBIT

Question 27

what does CHA2DS2VASc include as risk predictors?

Answer 27

Congestive HF HTN Age Diabetes Prior stroke/tia age 65-74 sex ... 1 point each or age 2 points and 1 point if Female high risk >1

Question 28

ORBIT risk predictor... 1 point for each RF

Answer 28

older age reduced Hb/ anaemia bleeding Hx induff kidney func <60 Tx w antiplatelet ... high risk >4

Question 29

what are the advantages of DOACs compared to warfarin

Answer 29

predictable pk allow fixed dosing no need for blood monitoring less food and drug interactions

Question 30

disadvantages of doacs?

Answer 30

mainly renally excreted so dose adjustments not easy to reverse cannot use INR as measure of coagulation

Question 31

what are direct factor Xa inhibitors?

Answer 31

Rivaroxaban Apixaban Edoxaban

Question 32

what is a direct thrombin inhibitor?

Answer 32

Dabigatran

Question 33

Anticoagulation with a DOAC is recommended in all patients with AF and a CHA2DS2‑VASc score of

Answer 33

2+ taking into account bleeding risk

Question 34

If the DOAC is not tolerated or not suitable what may be used instead

Answer 34

vit k antagonist like warfarin

Question 35

what does warfarin inhibit?

Answer 35

clotting factors II, VIII, IX and X

Question 36

give a benefit of using warfarin as an anticoagulant?

Answer 36

seen with INR 2-3, with low INR increasing risk of stroke and high INR increasing bleeding risk

Question 37

Prescribing warfarin safely could be challenging why?

Answer 37

NTI and variability in dose needed to get target INR

Question 38

what different things can an ecg test for?

Answer 38

heartbeat rate and regularity heart damage effect of drugs or devices

Question 39

how does an ecg work

Answer 39

signal strip is graphic tracing of electrical activity of heart, measures time takes foor initial impulse to fire at sinoatrial node and end in contracting ventricles

Question 40

what happens at the p wave of an ECG?

Answer 40

atria contract to pump blood into ventricles

Question 41

What happens in the QRS complex?

Answer 41

ventricles contracting to pump out blood

Question 42

what does the ST segment show?

Answer 42

end of ventricular contraction

Question 43

in a patient with AF, what may be seen on an ECG?

Answer 43

many lines for p wave as many fibrillations

Question 44

what is the t wave?

Answer 44

the resting period of the ventricles

Question 45

You are clinically screening a drug chart for a patient who is on digoxin. The patient is prescribed 125micrograms daily, the dose range in the BNF is 62.5micrograms to 250micrograms. What can you check to know the dose is ok for your patient?

Answer 45

The pulse, if it is high then a higher dose is needed, if the pulse is low then the dose is too high and needs to be reduced.

Question 46

Your patient is on apixaban for AF, they are admitted to hospital and are prescribed enoxaparin 40mg SC daily as thromboprophylaxis, is this ok?

Answer 46

NO! if patients are anticoagulated they do not need prophylaxis this is a bleeding risk.

Question 47

why are people with AF at an increased risk of having a stroke?

Answer 47

NVAF is associated with a x5 increase in the risk of ischaemic stroke. An ischaemic stroke is a result of embolism of a thrombus that forms predominantly within the left atria due to sluggish blood flow within the fibrillating atria.