Cardiology 10 - Atrial Fibrillation

Question 1

define atrial fibrillation

Answer 1

disorganised electrical activity leading to uncoordinated and irregular atrial contraction

Question 2

4 consequences of AF

Answer 2

irregularly irregular heart beat
tachycardia
heart failure due to poor diastolic filling
risk of stroke

Question 3

4 possible presenting symptoms of AF

Answer 3

palpitations
shortness of breath
syncope (dizzy or fainting)
assoc conditions (stroke, sepsis, thyrotox)

Question 4

2 differentials for irregularly irregular pulse

Answer 4

atrial fibrillation

ventricular ectopics

Question 5

4 features of AF on an ECG

Answer 5

absent p waves
irregularly irregular rhythm
narrow QRS complexes
tachycardia

Question 6

define valvular AF

Answer 6

AF found in patients with severe mitral stenosis or mechanical heart valve (which likely caused it)

Question 7

5 most common causes of AF

Answer 7

sepsis 
mitral valve pathology 
ischaemic heart disease
thyrotoxicosis 
hypertension

Question 8

3 aspects of treating AF

Answer 8

rate control
rhythm control
anticoagulation

Question 9

4 contraindications for rate control in AF (i.e. indications for first line rhythm control)

Answer 9

• reversible cause
• new onset <48 hrs AF
• AF is causing heart fail
• symptomatic on rate control

Question 10

give options 1,2,3 for rate control in AF

Answer 10

1. beta blocker (e.g. atenolol 50-100mg OD)
2. calcium-channel blocker (e.g. diltiazem)
3. digoxin (if sedentary - monitor as toxicity risk)

Question 11

4 options for rhythm control in AF

Answer 11

1. electrical or medical cardioversion
2. beta blockers (1st line)
3. dronedarone (maintenance therapy after cardioversion)
4. amiodarone (if LV dysfunction)

Question 12

define choice between immediate vs delayed cardioverison

Answer 12

immediate = if AF <48 hours old or they are haemodynamically unstable

delayed = if opposite is true

Question 13

what is needed pre delayed cardioversion?

Answer 13

anticoagulation for 3 weeks prior

Question 14

describe 2 drug options for cardioversion and the electrical option

Answer 14

flecanide 1st line
amiodarone if structural heart disease

for DC cardioversion, sedate or anaesthetise + timed shocks

Question 15

define paroxysmal AF and its treatment

Answer 15

intermittent episodes lasting less than 48 hours

anticoagulate based on Chadsvasc
offer ‘pill in pocket’ therapy if infrequent and no structural heart disease

flecanide is used

Question 16

when should flecanide be avoided?

Answer 16

in atrial flutter as can cuase 1:1 AV conduction and thus v fast heart rate

Question 17

where does blood particular pool in AF?

Answer 17

atrial appendage

Question 18

define the risk of stroke in AF

Answer 18

roughly 5% a year, reduced to 2% with anticoagulation

this gives them a 3% risk of serious bleed a year

Question 19

define: 
warfarin 
INR 
which drugs/foods to avoid alongside
reversing warfarin

Answer 19

vitamin K antagonist prolonging prothrombin time
INR = PT patient vs normal
target 2-3 usually
avoid cytochrome P450 affectors (e.g. especially Abx)
beware high vit K veg + cranberry juice / alcohol
half life 1-3 days, reverse with Vit K

Question 20

NOACs x3

why

Answer 20

apixiban, dabigitran BD
rivaroxaban OD

no monitoring, no major interactions, slightly better at stroke risk, slightly better with bleeds

Question 21

define the scoring of when you offer anticoagulation in Chadsvasc

Answer 21

definite if 2+
consider if 1
none if 0

Question 22

give the components of the CHA2DS2VASc score

Answer 22

Congestive heart failure
Hypertension
Age >75 (2 = scores 2)
Diabetes
Stroke/TIA (2= scores 2)
Vascular disease
Age 65-74
Sex female

Question 23

give the components of the HAS-BLED score

Answer 23

use an online calculator - provides yearly bleeding risk on anticoag

HTN
Abnormal renal /liver
Stroke
Bleeding
Labile INRs
Elderly
Drugs or alcohol