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Cardio-Resp > Arrhythmias: Atrial fibrillation > Flashcards

Arrhythmias: Atrial fibrillation Flashcards

1
Q

Define atrial fibrillation

A

Irregular uncoordinated contraction of the atria

Commonly originates near the pulmonary veins.

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2
Q

Name five causes of atrial fibrillation

A
  • Ischaemic heart disease
  • HTN
  • Valve disease
  • MI
  • Heart failure
  • Cardiothoracic surgery: occurs in 1/3
  • Rheumatic heart disease causing mitral stenosis
  • Non cardiac: infection; hyperthyroidism; electrolyte depletion; PE
  • Lifestyle: excess caffeine; smoking; alcohol
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3
Q

Name 2 significant risk factors for atrial fibrillation

A

Increased BMI Sleep apnoea

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4
Q

What ECG changes are seen with atrial fibrillation?

A
  • Absent P waves
  • Wavy baseline/f waves
  • Irregular-irregular R-R intervals
  • Narrow QRS complex
  • Variable R waves
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5
Q

Name four presenting features of atrial fibrillation

A

Asymptomatic: incidental finding (30%)

Suspect AF if irregular pulse with ot without:

  • Dyspnoea
  • Palpitations
  • Chest pain or discomfort
  • Syncope; dizziness
  • Stroke/TIA
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6
Q

How is atrial fibrillation classified?

A
  • Paroxysmal: <7d duration, commoner in younger
    • Acute: onset within previous 48h
  • Persistent: >7d duration
  • Permanent:
    • ​Fails to terminate using cardioversion; or
    • Longstanding with no further attempts to restore sinus rhythm
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7
Q

Name two complications of atrial fibrillation

A
  • Stroke/TIA
  • Heart failure
  • Tachycardia-induced cardiomyopathy
  • Critical cardiac ischaemia
  • Reduced QOL
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8
Q

What is the CHADS2-VASc score? Outline the score

A

Stroke risk score: Need for anticoagulation in non-valvular AF.

  • Congestive heart failure - 1
  • Hypertension - 1
  • Age 65 to 74 - 1
  • Diabetes mellitus -1
  • Stroke/TIA - 2
  • Vascular disease - 1
  • Age 75+ - 2
  • Sex category (female) - 1

0: Do not offer anticoagulation

1: Consider (male); do not offer (female)

2+: Offer anticoagulation

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9
Q

What is the HAS-BLED score?

A

Risk of bleeding assessment for patients on anticoagulation.

  • Hypertension - 1
  • Abnormal liver or renal function - 1 or 2
  • Stroke - 1
  • Bleeding - 1
  • Labile INR - 1
  • Elderly (>65) - 1
  • Medication predisposing bleeding or alcohol - 1 or 2
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10
Q

What determines the use of anticoagulants in atrial fibrillation?

A

Anticoagulation therapy is indicated when the risk of stroke > risk of bleeding

CHADS2-VASc and HAS-BLED scores are used to assess this

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11
Q

Which atrial fibrillation patients are indicated for anticoagulation?

A

Warfarin for all patients with:

  • Rheumatic mitral stenosis
  • Prosthetic heart valves

Offered to AF with CHADS2-VASc score 2+

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12
Q

Summarise the immediate management of atrial fibrillation

A
  • Haemodynamic instability: emergency electrical cardioversion
    • If >48h: TOE to assess atrial clots
  • No haemodynamic instablility:
    • Onset within 48h: Rate or rhythm control
    • Onset after 48h: Rate control
      • If for DC cardioversion: needs 3/52 anticoagulation before
  • Treat any underlying causes

Rate control: Beta-blockes, Diltiazem, Digoxin

Rhythm control: Flecainide or amiodarone; DC cardioversion

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13
Q

Give two indications for DC cardioversion as management of atrial fibrillation?

A
  • Emergency: haemodynamic instability or shock
    • >48h requires TOE to assess atrial thrombus
  • Continuous AF with >48hr duration
    • Will require 3wk warfarin or dabigatran prior
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14
Q

Outline Singh-Vaughan Williams classification of antiarrhythmic drugs

A
  • Ia: Intermediate Na channel blockers - Quinidine, procainamide
  • Ib: Fast Na channel blockers - Lidocaine, phenytoin
  • Ic: Slow Na channel blockers - Flecainide, Prepafenone
  • II: Beta-blockers - Propranolol, metoprolol, bisoprolol etc.
  • III: K channel blockers - Amiodarone, sotalol
  • IV: CCBs - Verapamil, diltiazem
  • Other: Adenosine, digoxin
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15
Q

Name two contraindications for both Flecainide and Amiodarone

A
  • Structural heart disease
  • Ischaemic heart disease
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16
Q

Outline the long-term management of atrial fibrillation

A

Stroke prevention: Oral anticoagulant

Symptom management

  • Rate control
    • Beta-blocker or CCB (diltiazem)
    • Digoxin: consider if sedentary
    • Combination therapy of 2 of the above
  • Rhythm control
    • Beta-blockers
    • Flecainide
    • Dronedarone: used after successful cardioversion
    • Amiodarone: heart failure; LV impairment
    • AVN ‘Pace and ablate’; Implantable cardioverter defibrillator
  • Electrical cardioversion: consider for persistent AF
    • Consider adding amiodarone to maintain sinus rhythm afterwards
17
Q

Name three side effects and three absolute contraindications of beta-blockers

A

Side-effects:

  • GI upset
  • Bradycardia
  • Heart failure; hypotension
  • Bronchospasm
  • Cold peripheries

Absolute contraindications: Asthma; Marked bradycardia; Heart block

  • Avoid non-dihydropyridine CCB due to risk of severe hypotension
18
Q

Name three side-effects and three contraindications of CCBs

A

Verapamil SEs:

  • Constipation, N+V
  • Flushing
  • Headaches; dizziness; fatigue

Contraindications: Heart failure, 2nd or 3rd heart block, cardiogenic shock

  • Avoid B-blockers due to risk of severe hypotension
19
Q

What monitoring is required whilst taking digoxin?

A

Renal function due to its narrow therapeutic index

Reduced in impaired renal function to minimise risk of digoxin toxicity.

20
Q

Describe digoxin toxicity

A

Chronic digoxin toxicity is associated with one-week-mortality of 15-30%

Characterised by GI distress; Hyperkalaemia; Life-threatening arrhythmias

Treatment: Digibind

21
Q

Name three common and three significant side-effects of amiodarone

A
  • Common: Photosensitivity, thyroid dysfunction, impaired night vision, bradycardia, raised serum transaminases
  • Rare but significant: Pulmonary fibrosis, cirrhosis, optic neuritis, blue-grey skin pigmentation
22
Q

Differentiate between the different anticoagulation therapies used in atrial fibrillation

A
  • Warfarin: Vitamin K reductase inhibitor
    • Dose adjusted to maintain INR 2.0-3.0 in AF
    • Requires regular INR blood monitoring
    • Antidote: Vitamin K
    • Well known drug profile
    • Significant drug interactions
  • NOACs: Apixaban; rivaroxaban; Dabigatran
    • Rapid onset; shorter half-life
    • Does not require blood monitoring
    • Fewer drug interactions
    • Unlicensed for valvular heart disease or mechanical heart valves
    • Avoid in liver or renal impairment

Cardio-Resp (26 decks)

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