Week 13: Atrial Fibrillation (AF) Flashcards by C L

What is AF? (3)

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

160-180 bpm
Slower in elderly.

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What can irregular atrial contractions result to? (1)

Blood stasis clot formation

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What is paroxysmal AF? (3)

Episodes lasting > 30 sec but < 7 days.

Often < 48 hrs

Self-limiting + recurrent

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What is persistent AF? (3)

Episodes lasting > 7 days

or < 7 days but needs cardioversion

Spontaneous termination of arrhythmia is unlikely to occur.

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What is permanent AF? (2)

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

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What is longstanding/permanent AF? (2)

> 1 yr
Cardioversion has not been indicated or attempted.

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What are the common causes of AF? (5)

Hypertension
Ischaemic Heart Disease
Myocardial Infarction
Valvular Heart Disease
Hyperthyroidism

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

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

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

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

Thyroxine
Bronchodilators (Salbutamol)

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What lifestyle factors can cause AF? (4)

Excessive caffeine
Alcohol abuse
Obesity
Smoking

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

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

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What are the potential complications for AF? (6)

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

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What are the common symptoms of AF? (10)

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

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

Manual pulse palpation to assess for irregular pulse.

12-lead ECG

24hr ambulatory ECG if paroxysmal AF suspected.

Echocardiography

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

Irregular pattern.
P-waves = irregular.

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

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.

Explain the management process of AF. (6)

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

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

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.

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

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

Explain the treatment interventions for acute AF. (5)

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

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

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)

What are common s/e of beta blockers?

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

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

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)

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

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

What would be considered as paroxysmal AF? (4)

– 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

Explain the process of assessing stroke risk. (4)

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.

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

* 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.

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

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

Explain the tx regimen for new onset AF (1)

Heparin at initial presentation and continue until appropriate anticoagulant started.

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

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

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

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)

What does personalised AF care consist of? (7)

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