AF Flashcards

1
Q

T/F AF is rare below 50 yo?

A

true but becomes more prevalent with increasing age

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2
Q

what is af?

A

Abnormal, disorganised electrical signals fired causing the atria to quiver

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3
Q

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

A

valvular or non valvular

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4
Q

‘valvular’ AF being associated with patients with …?

A

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

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5
Q

what are the risk factors for AF

A

hypertension, atherosclerosis and hyperthyroidism, over 65

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6
Q

what are the symptoms of AF

A

dizziness, palpitations, sob, tiredness

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7
Q

true or false AF can be asymptomatic?

A

true

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8
Q

a normal HR should be regular and at rest between

A

60-100bpm

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9
Q

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

A

neck
wrist

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10
Q

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

A

manual pulse palpitation

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11
Q

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

A

12 lead ecg

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12
Q

what are the 2 approaches of treating af?

A

rate and rhythm control

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13
Q

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?

A

4

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14
Q

ventricular rate can be controlled with what 2 drug classes?

A

BB or rate limiting CCB

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15
Q

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

A

-> worsen pulmonary oedema caused by hf

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16
Q

what is next after monotherapy does not work

A

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

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17
Q

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

A

usually only effective for controlling ventricular rate at rest

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18
Q

explain how digoxin works as a cardiac glycoside?

A

increases force of myocardial contraction and reduces conductivity within av node

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19
Q

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

A

1-2

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20
Q

what is primary method of excretion for digoxin?

A

renal - so be aware of dosing

21
Q

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

A

directly inhibits the transmembrane Na/K/ATPase exchange pump

22
Q

cardiac adverse effects of digoxin (toxicity)?

A

ventricular arrhythmias
av block
atrial arrhythmias
sinus bradycardia

23
Q

non cardiac adverse effects of digoxin tox?

A

nausea/ vomiting
anorexia
abdominal pain
visual disturbances
confusion

24
Q

why are people with af at higher risk of stroke

A

sluggish blood flow within the fibrillating atria

25
Q

what tool calculates the risk of stroke?

A

CHA2DS2VASc

26
Q

what tool calculates the risk of bleeding?

A

ORBIT

27
Q

what does CHA2DS2VASc include as risk predictors?

A

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

28
Q

ORBIT risk predictor… 1 point for each RF

A

older age
reduced Hb/ anaemia
bleeding Hx
induff kidney func <60
Tx w antiplatelet


high risk >4

29
Q

what are the advantages of DOACs compared to warfarin

A

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

30
Q

disadvantages of doacs?

A

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

31
Q

what are direct factor Xa inhibitors?

A

Rivaroxaban
Apixaban
Edoxaban

32
Q

what is a direct thrombin inhibitor?

A

Dabigatran

33
Q

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

A

2+ taking into account bleeding risk

34
Q

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

A

vit k antagonist like warfarin

35
Q

what does warfarin inhibit?

A

clotting factors II, VIII, IX and X

36
Q

give a benefit of using warfarin as an anticoagulant?

A

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

37
Q

Prescribing warfarin safely could be challenging why?

A

NTI
and variability in dose needed to get target INR

38
Q

what different things can an ecg test for?

A

heartbeat rate and regularity
heart damage
effect of drugs or devices

39
Q

how does an ecg work

A

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

40
Q

what happens at the p wave of an ECG?

A

atria contract to pump blood into ventricles

41
Q

What happens in the QRS complex?

A

ventricles contracting to pump out blood

42
Q

what does the ST segment show?

A

end of ventricular contraction

43
Q

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

A

many lines for p wave as many fibrillations

44
Q

what is the t wave?

A

the resting period of the ventricles

45
Q

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?

A

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.

46
Q

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

A

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

47
Q

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

A

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.

48
Q
A