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### > Week 13: Atrial Fibrillation (AF) > Flashcards

Week 13: Atrial Fibrillation (AF) Flashcards

1
Q

What is AF? (3)

A

Irregular, disorganised electrical activity in the atria.

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

AV nodes receive more electrical impulses than it can conduct causing irregular ventricular rhythm.

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2
Q

What is the ventricular rate of untreated AF? (2)

A

160-180 bpm
Slower in elderly.

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3
Q

What can irregular atrial contractions result to? (1)

A

Blood stasis clot formation

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4
Q

What is paroxysmal AF? (3)

A

Episodes lasting > 30 sec but < 7 days.

Often < 48 hrs

Self-limiting + recurrent

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5
Q

What is persistent AF? (3)

A

Episodes lasting > 7 days

or < 7 days but needs cardioversion

Spontaneous termination of arrhythmia is unlikely to occur.

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6
Q

What is permanent AF? (2)

A

Fails to terminate after cardioversion.
Terminated but relapse within 24 hrs.

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7
Q

What is longstanding/permanent AF? (2)

A

> 1 yr
Cardioversion has not been indicated or attempted.

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8
Q

What are the common causes of AF? (5)

A

Hypertension
Ischaemic Heart Disease
Myocardial Infarction
Valvular Heart Disease
Hyperthyroidism

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9
Q

What are the cardiac/valvular causes of AF? (8)

A

Congestive HF, rheumatic valvular disease, atrial or ventricular hypertrophy,
congenital heart disease, Wolf-Parkinson- White syndrome, sick-sinus
syndrome. Inflammatory disease (pericarditis, amyloidosis, myocarditis)

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10
Q

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

A

Acute infection, thyrotoxicosis, diabetes, electrolyte depletion
(hypokalaemia, hyponatraemia), cancer.

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11
Q

Give e.g. of medications that can cause AF. (2)

A

Thyroxine
Bronchodilators (Salbutamol)

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12
Q

What lifestyle factors can cause AF? (4)

A

Excessive caffeine
Alcohol abuse
Obesity
Smoking

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13
Q

What is the common prevalence rate of AF? (1)

A

Increases with age (40 yrs = 1/4 lifetime risk of AF)

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14
Q

What are the potential complications for AF? (6)

A

Stroke/Thromboembolism risk (x5 higher)
HF
Tachycardia-induced cardiomyopathy
Critical cardiac ischaemia
Reduced QofL
Increased mortality rate.

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15
Q

What are the common symptoms of AF? (10)

A

Breathlessness
Palpitations
Chest Discomfort
Syncope
Dizziness
Stroke/TIA
Reduced exercise tolerance
Malaise
Polyuria
Decreased in mentation

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16
Q

What investigations are used to help diagnose a patient with AF? (4)

A

Manual pulse palpation to assess for irregular pulse.

12-lead ECG

24hr ambulatory ECG if paroxysmal AF suspected.

Echocardiography

17
Q

What is the difference between AF and a normal ECG result? (2)

A

Irregular pattern.
P-waves = irregular.

18
Q

What health conditions would be considered as differential diagnosis of AF? (5)

A

Atrial Flutter - saw tooth pattern

Atrial extrasystoles - common but can cause an irregular pulse.

Ventricular ectopic beats.

Sinus tachycardia = SR > 100bpm.

Supraventricular tachycardias incl atrial tachycardia, AVNRT tachycardia and WPW.

19
Q

Explain the management process of AF. (6)

A

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

Underlying causes:
- Cardiac causes = HPT, VHD, HF, IHD.
- Respiratory causes = chest infecitons, PE + LC.
- Systemic causes = excenssive alcohol intake, thyrotoxicosis, electrolyte depletion, infections + diabetes.

Treat Arrhythmias:
- Rate control = BB or rate-limiting CCB.
- Rhythm control - cardioversion.

Assess stroke risk:
- Use CHA2DS2VASc

Risk v. benefits anticoagulation:
- Use ORBIT tool

Follow up:
- Rate control tx
- Anticoagulants

20
Q

What are the treatment options for rate control in AF? (4)

A

1st line (unless suitable for rhythm control/ investigations for rhythm ongoing:
- Beta-blocker (NOT sotalol)
- Or rate-limiting CCB (Diltiazem or Verapamil)
- Digoxin monotherapy:
- Consider if little exercise activity or other options ruled out.

21
Q

When would it be appropriate to consider rhythm control (cardioversion)? (6)

A
  • New onset AF (<48 hours)
    – Reversible cause (e.g. chest infection)
    – HF caused/worsened by AF
    – Atrial flutter suitable for ablation
    – Clinician judgement of patient
    – May take time to determine if suitable for rhythm- in interim give rate
22
Q

Explain the treatment interventions for acute AF. (5)

A

Consider either pharmacological or electrical cardioversion for
new-onset AF who will be treated by rhythm control.

  • Pharmacological cardioversion, offer:
    – Flecainide or amiodarone if there is no evidence of structural or ischaemic
    heart disease or
    amiodarone if there is evidence of structural heart disease.
    – If >48 hrs (or uncertain) and long-term rhythm control, delay cardioversion
    until maintained on therapeutic anticoagulation for a minimum of 3 weeks.
    During this period offer rate control as appropriate
  • Anticoagulation
  • Bleed risk
23
Q

Explain the use of beta blockers for rate control in AF.

A

Normally avoid in people with history of obstructive airways
disease
* Licensed products
– Atenolol, acebutolol, metoprolol, nadolol, oxprenolol, propranolol

– Lone AF – atenolol

– AF with Hx MI – metoprolol, propranolol, atenolol

– AF with Hx HF – bisoprolol, carvedilol or nebivolol

  • Atenolol
    – 50-100mg daily
    – Monitor HR and BP to titrate against response

(Familiarise yourselves with counselling points)

24
Q

What are common s/e of beta blockers?

A
  • Bradycardia and hypotension
  • Cold extremities
  • Disturbed sleep and nightmares
    – less likely with water soluble agents such as atenolol
  • Sexual dysfunction
  • Can cause hypoglycaemia or hyperglycaemia in patients +/-
    diabetes.
  • Mask signs of a hypoglycaemia
  • Withdrawal effects
  • Fatigue
25
Q

Explain the use of CCBs for rate control in AF. (4)

A

Rate limiting CCB used in AF
– Diltiazem and verapamil
* Off label use of diltiazem

  • Interaction with other medication
    – Simvastatin capped at 20mg
  • Avoid in HF (not amlodipine)
    – Further depress cardiac function and exacerbate
    symptoms
  • Side effects: Headache, dizziness, hypotension,
    bradycardia (refer to BNF for additional)
26
Q

Explain the use of pill in the pocket. (2)

A

Flecainide

Infrequent paroxysms and few symptoms induced by known triggers (alcohol, caffeine).

27
Q

What would be considered as paroxysmal AF? (4)

A

– No hx of LV dysfunction, or valvular or IHD and
– Have hx of infrequent symptomatic episodes and
– Have SBP >100 mmHg and resting HR > 70bpm and
– Able to understand how to take and use medicine

28
Q

Explain the process of assessing stroke risk. (4)

A

CHA2DS2-VASc
– Symptomatic or asymptomatic paroxysmal,
persistent or permanent atrial fibrillation
– Atrial flutter
– A continuing risk of arrhythmia recurrence after
cardioversion back to sinus rhythm or catheter
ablation.

29
Q

Explain the process of using anticoagulation in AF. (7)

A
  • Offer if CHA 2DS 2VASc of 2+
  • Consider in male biological sex with a score of 1
  • Apixaban, dabigatran, edoxaban and rivaroxaban are all
    recommended as options
  • DOAC contraindicated, not tolerated or not suitable in people
    with AF, offer a vitamin K antagonist
    – If already on warfarin, discuss the option of switching treatment at their
    next routine appointment, taking into account the person’s time in TTR
  • Do not offer anticoagulation to people aged under 65 years
    with atrial fibrillation and no risk factors other than their sex
  • Do not withhold anticoagulation solely because of a person’s
    age or their risk of falls.
30
Q

What do you need to consider when considering use of anticoagulants as tx? (5)

A

For most people the benefit of anticoagulation
outweighs the bleeding risk.

  • For people with an increased risk of bleeding, the
    benefit of anticoagulation may not always outweigh
    the bleeding risk, and careful monitoring of bleeding
    risk is important
  • If not taking anticoagulant
    – Review at 65 years
    – Or if develop diabetes, heart failure, peripheral arterial
    disease, coronary heart disease, stroke, transient
    ischaemic attack or systemic thromboembolism
31
Q

Explain the tx regimen for new onset AF (1)

A

Heparin at initial presentation and continue until appropriate anticoagulant started.

32
Q

Explain the tx regimen for confirmed AF diagnosis. (5)

A

Onset = < 48 hrs.
- Offer oral anticoagulation if:
* Stable sinus rhythm is not successfully restored within the same 48-hour
period after onset
* High risk of AF recurrence (history of failed cardioversion, structural heart
disease, prolonged AF (>12 months), or previous recurrences
* Based on CHADSc-VASc
* Unsure time since onset- assess as per CHADsVASc

33
Q

What do you need to consider when assessing bleeding risk? (2)

A

Assess when:
1. Starting anticoagulation
2. Reviewing people taking anticoagulants

  • ORBIT tool
    – Higher accuracy in predicting absolute bleeding
    risk than other bleeding risk tools (HASBLED)
34
Q

What does personalised AF care consist of? (7)

A

Stroke awareness and measures to prevent stroke
* Rate control or
* Rhythm control (if appropriate)
* Who to contact for advice/ psychological support if needed
* Information on cause, effects and possible complications of
atrial fibrillation
* Management of rate and rhythm control
* Anticoagulation

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