Atrial Fibrilation

Question 1

what is atrial fibrillation?

Answer 1

when the electrical activity of the atria becomes disorganised
causes fibrillation (random muscle twitching) of the atria
leads to an irregularly irregular pulse

Question 2

what are the overall effects of atrial fibrillation?

Answer 2

irregularly irregular ventricular contractions
tachycardia
heart failure - due to impaired filling of ventricles during diastole
increased risk of stroke

Question 3

what does the sinoatrial node normally do?

Answer 3

produces organised electrical activity that coordinates the contraction of the atria

Question 4

what happens to the electricity in the heart in atrial fibrillation?

Answer 4

it becomes disorganised
the chaotic electricity overrides the normal electricity from the sinoatrial node

Question 5

what does the disorganised electricity in the heart lead?

Answer 5

uncoordinated, rapid, irregular atrial contractions

Question 6

what happens when the disorganised electricity overrides the normal electricity from the SA node?

Answer 6

the disorganised electricity passes to the ventricles
causing irregularly irregular ventricular contractions

Question 7

what can uncoordinated atrial contractions cause blood to do?

Answer 7

stagnate in the atria
forming thrombus (blood clot)

Question 8

what can a thrombus in the left atrium cause?

Answer 8

ischaemia stroke
if the blood clot travels to the brain and blocks a cerebral artery

Question 9

what is the risk of stroke associated with atrial fibrillation?

Answer 9

patients with AF are at a 5x higher risk than usual

Question 10

what are the causes of atrial fibrillation?

Answer 10

Sepsis
Mitral valve pathology
Ischaemic heart disease
Thyrotoxicosis
Hypertension

Question 11

what are lifestyle causes of AF?

Answer 11

alcohol
caffeine

Question 12

what are patients with AF often?

Answer 12

asymptomatic

Question 13

when is AF commonly found?

Answer 13

accidentally
may be diagnosed after a stroke

Question 14

how may patients with AF present?

Answer 14

palpitations
shortness of breath
dizziness/syncope
symptoms of associated conditions - stroke, sepsis, thyrotoxicosis

Question 15

what is a key exam finding?

Answer 15

irregularly irregular pulse

Question 16

what does an irregularly irregular pulse mean?

Answer 16

the patient has either atrial fibrillation or ventricular ectopics

Question 17

what suggests a diagnosis of ventricular ectopics and why?

Answer 17

a normal heart whilst exercising
ventricular ectopics disappears once the heart rate is above a certain threshold

Question 18

what do all patients with an irregularly irregular pulse require?

Answer 18

ECG

Question 19

what are the ECG findings for atrial fibrillation?

Answer 19

absent P waves
narrow QRS complex tachycardia
irregularly irregular ventricular rhythm

Question 20

what may an echocardiogram be used for in atrial fibrillation?

Answer 20

further investigations of:
valvular heart disease
heart failure
planned cardioversion

Question 21

what is paroxysmal atrial fibrillation?

Answer 21

reoccurring episodes of atrial fibrillation that spontaneously go back to normal sinus rhytm

Question 22

how long can episodes of paroxysmal atrial fibrillation last?

Answer 22

between 30s and 48hrs

Question 23

what are patients with suspected paroxysmal atrial fibrillation and a normal ECG given for further investigation?

Answer 23

24hr ambulatory ECG
cardiac event recorder listing 1-2 weeks

Question 24

what is valvular atrial fibrillation?

Answer 24

atrial fibrillation with significant mitral stenosis or a mechanical heart valve
the assumption is that the valve pathology has left to AF

Question 25

what is non-valvular AF?

Answer 25

AF with no valvular pathology or other valvular pathology - i.e. mitral regurgitation or aortic stenosis

Question 26

what are the principles of management for atrial fibrillation?

Answer 26

rate or rhythm control anticoagulation - prevent strokes

Question 27

how do the ventricles fill with blood when the atrial contractions are uncoordinated?

Answer 27

gravity and suction - much less effective increased heart rate = less time for the ventricles to fill = decreased cardiac output

Question 28

what are the aims or rate control?

Answer 28

to get the heart rate below 100bpm and extend the time of diastole for the ventricles to fill

Question 29

who is rate control not first line for when managing atrial fibrillation?

Answer 29

reversible causes of AF new onset AF - within the last 48hrs HF caused by AF symptoms despite effectively rate controlled

Question 30

what medications are used for rate control?

Answer 30

beta blockers are first line - atenolol or bisoprolol calcium channel blockers - dilimiazem or verapamil but should be avoided in those with HF digoxin - only for sedentary people with persistent AF, needs monitoring and there is a risk of toxicity

Question 31

when is rhythm control used?

Answer 31

when rate control is not : reversible causes of AF new onset AF - within last 48hrs HF caused by AF symptomatic despite being effectively rate controlled

Question 32

what are the aims of rhythm control?

Answer 32

to return the heart to normal sinus rhythm

Question 33

what are the two methods of rhythm control?

Answer 33

cardioversion long-term rhythm control - medication

Question 34

what are the two types of cardio version?

Answer 34

immediate delayed

Question 35

when is immediate cardoversion used?

Answer 35

when atrial fibrillation: has been present for less than 48hrs is causing life-threatening haemodynamic instability

Question 36

what are the two methods of immediate cardio version?

Answer 36

pharmocological electrical

Question 37

what drugs can be used for pharmacological cardio version?

Answer 37

flecanide amiodarone - useful for patient with structural heart disease

Question 38

what is the aim of electrical cardio version?

Answer 38

to shock the heart back into sinus rhythm

Question 39

how is electrical cardioversion done?

Answer 39

with a cardiac defibrillator machine that delivers a controlled shock this is usually done under sedation or general anaesthetic

Question 40

when is delayed cardioversion used?

Answer 40

when atrial fibrillation; has been present for more than 48hrs and the patient is stable

Question 41

what type of cardioversion is recommended for delayed cardioversion?

Answer 41

electrical transoesophageal echocardiography-guided cardioversion is also an option when available

Question 42

what medication may be considered before and after a delayed cardioversion and why?

Answer 42

amiodarone to prevent atrial fibrillation from recurring

Question 43

what should a patient be for at least 3 weeks before a cardioversion and why?

Answer 43

anticoagulated within 48hrs before they may develop a thrombus reverting to sinus rhythm has a high risk of mobilising the clot and causing a stroke

Question 44

how are patients awaiting delayed cardioversion managed?

Answer 44

rate control

Question 45

what medications can be used for long-term rhythm control?

Answer 45

beta blockers are first line dronedarone is second line for maintaining sinus rhythm after a successful cardioversion amiodarone is useful for patients with heart failure or left ventricular dysfunction

Question 46

what may patients with paroxysmal atrial fibrillation be suitable for?

Answer 46

pill in the pocket

Question 47

what is pill in the pocket?

Answer 47

where patients take a pill to terminate their AF but only when they feel symptoms

Question 48

what is required for pill in the pocket?

Answer 48

infrequent episodes no structural heart disease identify signs of AF understand when to take pill

Question 49

what drug is usually used for pill in the pocket?

Answer 49

flecanide should still be anti coagulated if qualify

Question 50

what is the risk of flecanide in AF?

Answer 50

risk of converting atrial fibrillation into atrial flutter with 1:1 conduction to the ventricles = very fast ventricular rate