Atrial Fibrilation

Question 1

What is AF? (1)

Answer 1

Irregular, disorganised electrical activity in the atria.

Question 2

What are the main feature of AF? (3)

Answer 2

Supraventricular tachyarrhythmia

Rapid firing impulses -> disorganised atrial depolarisation and ineffective atrial contractions.

AV nodes receive more electrical impulses that it can conduct. -> Irregular ventricular rhythm.

Question 3

What is the ventricular rate of untreated AF? (1)

Answer 3

160-180bpm (slower in elderly)

Question 4

What is the effect of irregular atrial contractions? (1)

Answer 4

Blood status clot formation

Question 5

What is paroxysmal AF? (3)

Answer 5

Episode lasting > 30 seconds but < 7 days.
Often < 48 hrs
Self-limiting and recurrent.

Question 6

What is persistent AF? (3)

Answer 6

Episodes lasting > 7 days
Or < 7 days but needs cardioversion.
Spontaneous termination of arrhythmias = unlikely to occur.

Question 7

What is permanent AF? (3)

Answer 7

Fails to terminate using cardioversion.
Terminated but relapses within 24 hrs.
A.K.A. Long-standing AF (>1yr) where cardioversion hasn’t been indicated or attempted.

Question 8

What are the common causes of AF? (5)

Answer 8

Hypertension
IHD
MI
VHD
Hyperthyroidism

Question 9

What are the cardiac/valvular causes of AF? (7)

Answer 9

CHF
RVD
A/VH
CHD
Wolf-Parkinson-White syndrome
Sick-sinus syndrome
Inflammatory disease (pericarditis, amyloidosis, myocarditis)

Question 10

What are the non-cardiac causes of AF? (5)

Answer 10

Acute infection
Thyrotoxicosis
Diabetes
Electrolyte Depletion (low K/Na)
Medication: Thyroxine, Bronchodilators

Question 11

What lifestyle factors can cause AF? (4)

Answer 11

Excessive caffeine
Alcohol abuse
Obesity
Smoking

Question 12

What are the complications of AF? (5)

Answer 12

Stroke + thromboembolism
HF
Tachycardia-induced cardiomyopathy and critical cardiac ischaemia.
Reduced QofL
Higher risk of mortality.

Question 13

What are the main symptoms of AF? (5)

Answer 13

Breathlessness
Palpitations
Chest Discomfort
Syncope/Dizziness
Stroke/TIA

Question 14

What additional symptoms can be present for AF? (4)

Answer 14

Reduced exercise tolerance.
Malaise
Decreased in mentation
Polyuria

Question 15

Explain the diagnostic process of AF. (7)

Answer 15

Manual pulse palpation (irregular pulse)
12-lead ECG
If paroxysmal AF suspected: 24-hr ambulatory ECG.
Initial tests: FBC, Clotting profile, U+E, TFTs
Cardiac troponin, BNP, WCC, ESR, LFT.
CXR
Transthoracic Echocardiography (ESC - all patients. NICE - LT management, cardioversion considered, high risk of structural/functional cardiac disease)

Question 16

What is the main difference between AF + normal ECG? (1)

Answer 16

AF = no P waves v Normal = P waves before PR interval.

Question 17

What are the differential diagnoses of AF? (6)

Answer 17

Atrial flutter
Atrial extrasytoles
Ventricular ectopic beats
Sinus tachycardia
Supraventricular tachycardia (atrial tachycardia, AVNRT tachycardia + WPW)
Multi focal atrial tachycardia

Question 18

Define atrial flutter. (1)

Answer 18

Saw-tooth pattern of atrial activation on ECG.

Question 19

Define atrial extrasystoles. (1)

Answer 19

Common
Cause irregular pulse.

Question 20

Define sinus tachycardia. (1)

Answer 20

SR > 100bpm

Question 21

State the steps of managing AF. (5)

Answer 21

Admit:
- Haemodynamically unstable, rapid pulse (>150bpm) low BP (< 90mmHg)
- Loss of consciousness, severe dizziness/syncope, ongoing chest pain, increasing breathlessness.

Underlying causes:
- Cardiac causes (HPT, VHD, HF, IHD)
- Respiratory (Chest infections, PE + lung cancer)
- Systemic (Excessive alcohol intake, thyrotoxicosis, electrolyte depletion, infections and diabetes)

Treat the arrhythmias:
- Rate control (Beta-blocker or rate limiting CCB)
- Rhythm control (pharmacological or electrical cardioversion)

Assess stroke risk:
- CHA2Ds2VASc

Risks vs. Benefits:
- ORBIT

Follow up:
- Rate control tx
- Anticoagulants

Question 22

Explain rate control treatment of AF when haemodynamically stable. (4)

Answer 22

First line > 48 hrs unless suitable for rhythm control/investigations for rhythm ongoing.

Beta-blocker (NOT sotalol)

Or rate limiting CCB (Diltiazem/Verapamil)

Digoxin monotherapy (very little exercise or other options ruled out.)

Question 23

Explain rhythm control treatment of AF when haemodynamically stable. (7)

Answer 23

Cardioversion:
- Pharmaceutical +/- rhythm control for people with AF whose symptoms continue after HR has been controlled or for whom a rate control strategy hasn’t been successful.
- New onset AF (< 48 hrs)
- Revserible cause (e.g. chest infection)
- HF caused/worsened by AF
- Atrial flutter suitable for ablation
- Clinical judgement of px.
- May take time to determine if suitable for rhythm - in interim give rate.

Question 24

Explain the management of acute AF when haemodynamically unstable. (4)

Answer 24

Pharmacological/electrical cardioversion for new-onsent AF who’s going to be treated by rhythm control

Pharmacological cardioversion offer:
- Flecanide or Amiodarone (no structural or IHD) OR Amiodarone (structural HD)
- > 48 hrs (or uncertain) and LT rhythm control, delay cardioversion until maintained on therapeutic anticoagulation for min. 3.weeks. During this period offer rate control as appropriate.

Anticoagulation

Bleed risk (ORBIT)

Question 25

What condition should you avoid the use of Beta-blockers? (1)

Answer 25

Hx of obstructive airway disease (COPD/Asthma)

Question 26

Give e.g. of B-blockers used for AF rate control. (4)

Answer 26

Atenolol,Acebutolol, Metoprolol, Nadolol, Oxprenolol, Propanolol. Lone AF - Atenolol (50-100mg daily, monitor HR and BP to titrated against response.) AF with Hx MI - Metoprolol, Propranolol, Atenolol Af with Hx HF - Bisoprolol, Carvedilol or Nebivolol.

Question 27

What are the common s/e of beta blockers? (10)

Answer 27

Bradycardia/Hypotension Cold Extremities Disturbed sleep and nightmares (less likely with water soluble agents e.g. Atenolol) Sexual dysfunction Hypoglycaemia or Hyperglycaemia in patients +- diabetes Mask signs of hypoglycaemia Withdrawal effects Fatigue

Question 28

Explain the use of CCB in AF’s rate control. (4)

Answer 28

Rate-limiting (Diltiazem (off-label) + Verapamil) Simvastatin capped at 20mg Avoid in AF (not amlodipine) = further depresses cardiac function and exacerbate symptoms. S/e: Headache, dizziness, hypotension, bradycardia.

Question 29

What are the main features of Pill in the pocket? (3)

Answer 29

Flecainide Infrequent paroxysms and few symptoms indicted by known precipitants (alcohol, caffeine) Paroxysmal AF consider if: - No Hx of LV dysfunction/valvular/IHD and - Have Hx of infrequent symptomatic episodes and - Have SBP > 100 mmHg and resting HR > 70 bpm and - Able to understand how to take and use medicine.