Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

CCC > Atrial Fibrillation > Flashcards

Atrial Fibrillation Flashcards

1
Q

Atrial fibrillation (AF) is a common tachyarrhythmia mainly occurring in older patients but paroxysmal form can occur in younger patients.

What is the basic pathology underlying AF?

A

Conditions that:

  1. Raise atrial pressure
  2. Increase atrial muscle mass
  3. Atrial fibrosis
  4. Atrial inflammation

can all cause AF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the causes of AF?

A
  1. Rheumatic heart disease
  2. Alcohol
  3. Thyrotoxicosis/hyperthyroidism
  4. Hypertension*
  5. Heart failure*
    * Most common causes of AF in developed world
  6. Idiopathic or lone AF
    (genetic predisposition esp in young patients. 30-40% have at least one parent with AF. Genes assoc. with sodium, potassium channel, gap junction protein are implicated. Chromosomes 10, 6, 5 and 4 assoc with familial AF)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens to the atria in AF?

A

AF is maintained by continuous, rapid activation of the atria.

The atria responds electrically but there is no coordinated mechanical action and only some of the impulses are conducted to the ventricles.

The ventricular response depends on the rate and regularity of atrial activity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the clinical features of AF?

A

Symptoms are highly variable.

  1. Incidental finding (30%)
  2. Emergency with rapid palpitations, dyspnoea and/or chest pain
  3. Deterioration in exercise with ongoing AF
  4. Irregularly irregular pulse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the ECG changes seen in AF?

A

Absent p-waves

Irregular qrs complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Suspect AF in people with an irregular pulse, with or without any of the following:

=> Breathlessness.

=> Palpitations.

=> Chest discomfort.

=> Syncope or dizziness.

=> Reduced exercise tolerance, malaise/listlessness, decrease in mentation, or polyuria.

=> A potential complication of AF, such as stroke, TIA, or heart failure.

A

Past medical hx of
=> cardiac disease including valvular heart disease, coronary artery disease, hypertension, pericarditis, cardiomyopathy increases risk of AF

=> non-cardiac causes i.e. diabetes, thyroid disease, cancer and alcohol misuse

Suspectt paroxysmal AF if symptoms are episodic and less than 48h

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How is the diagnosis of AF confirmed?

A

ECG

=> no p waves
=> irregular QRS complex - irregular ventricular rate around 160-180bpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the differentials for AF?

A
  1. Atrial flutter — characterized by a saw-tooth pattern of regular atrial activation on the electrocardiogram.
  2. Atrial extrasystoles — common and may cause an irregular pulse.
  3. Ventricular ectopic beats.
  4. Sinus tachycardia — sinus rhythm with more than 100 beats per minute.
  5. Supraventricular tachycardias, including atrial tachycardia, atrioventricular nodal re-entry tachycardia, and Wolff-Parkinson-White syndrome.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 5 clinical classification of AF?

A
  1. First detected - irrespective of duration or severity of symptoms
  2. Paroxysmal - stops spontaneously within 7 days
  3. Persistent - continuous >7 days
  4. Longstanding persistent - continuous >1year
  5. Permanent
    * Classification is helpful in choosing between rhythm restoration and rate control management.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

NICE advocate using a rate control strategy except in a number of specific situations such as coexistent heart failure, first onset AF or where there is an obvious reversible cause, where rhythm control (cardioversion) may be used

A

INFO CARD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

AF MANAGEMENT: RATE CONTROL

Rate control should be offered as the first‑line treatment strategy for atrial fibrillation except in people:

=> whose AF has a reversible cause

=> who have heart failure thought to be primarily caused by atrial fibrillation

=> with new‑onset atrial fibrillation (< 48 hours)

=> with atrial flutter whose condition is considered suitable for an ablation strategy to restore sinus rhythm

=> for whom a rhythm‑control strategy would be more suitable based on clinical judgement

A

Medications:

  1. Beta-blocker i.e. atenolol
    => contraindicated in asthma
  2. Calcium channel blocker i.e. diltiazem or verapamil
    => contraindicated in HF, bradycardia, hypotension
  3. Digoxin
    => not 1st line anymore as less effective in controlling heart rate during exercise
    => should only be considered if person does 0 - very little physical exercise or other rate-limiting drug option ruled out
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

AF MANAGEMENT: Rhythm control

Agents used to maintain sinus rhythm in patients with a history of atrial fibrillation

=> beta-blockers

=> dronedarone: second-line in patients following cardioversion

=> amiodarone: particularly if coexisting heart failure

A

NICE recommends the use of catheter ablation for those with AF who have not responded to or wish to avoid, antiarrhythmic medication.

Technical aspects:
=> the aim is to ablate the faulty electrical pathways that are resulting in atrial fibrillation.
=> procedure is performed percutaneously, typically via groin
=> both radiofrequency (uses heat generated from medium frequency alternating current) and cryotherapy can be used to ablate the tissue

Anticoagulation:
=> Should be used 4 weeks before and during the procedure
it should be remember that catheter ablation controls the rhythm but does not reduce the stroke risk, even if patients remain in sinus rhythm. Therefore, patients still require anticoagulation as per their CHA2DS2-VASc score
if score = 0: 2 months anticoagulation recommended
if score > 1: longterm anticoagulation recommended

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is catheter ablation?

A

NICE recommends the use of catheter ablation for those with AF who have not responded to or wish to avoid, antiarrhythmic medication.

Technical aspects:
=> the aim is to ablate the faulty electrical pathways that are resulting in atrial fibrillation.
=> procedure is performed percutaneously, typically via groin
=> both radiofrequency (uses heat generated from medium frequency alternating current) and cryotherapy can be used to ablate the tissue

Anticoagulation:
=> Should be used 4 weeks before and during the procedure

=> catheter ablation controls the rhythm but does not reduce the stroke risk, even if patients remain in sinus rhythm.

=> Therefore, patients still require anticoagulation as per their CHA2DS2-VASc score
if score = 0: 2 months anticoagulation recommended
if score > 1: longterm anticoagulation recommended

Outcome:
Complications include: 
=> cardiac tamponade
=> stroke
=> pulmonary vein stenosis

Success rate:
=> around 50% of patients experience an early recurrence (within 3 months) of AF that often resolves spontaneously
longer term, after 3 years,
=> around 55% of patients who’ve had a single procedure remain in sinus rhythm. Of patients who’ve undergone multiple procedures around 80% are in sinus rhythm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Rhythm control management:

  1. Describe the rhythm control management in younger, symptomatic and physically active patients.
  2. Describe the rhythm control management in patients with heart failure or left ventricular hypertrophy ;
    coronary artery disease ;
    paroxysmal atrial fibrillation or early persistent atrial fibrillation (atrial dilation)
A
  1. Any class of anti-arrhythmic drug can be given to young, symptomatic and physically active patients. Amiodarone should be kept as last resort due to its extra-cardiac adverse effects.

2i. Heart failure/LVH : Amiodarone only
ii Coronary artery disease : Sotalol or amiodarone
iii. Paroxysmal atrial fibrillation/early persistent atrial fibrillation : Left atrial ablation

  1. Ectopic trigger for atrial fibrillation found in pulmonary veins : radio frequency or cryothermal energy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Which group of patients is rate control therapy appropriate in?

A
  1. Patients with permanent form of the arrhythmia assoc with symptoms that can be improved by slowing down heart rate
  2. > 65yr old patients with recurrent atrial tachyarrhythmias
  3. Persistent tachyarrythmias and failed cardioversions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Atrial fibrillation: Pharmacological cardioversion

A

Agents with proven efficacy in the pharmacological cardioversion of atrial fibrillation:

=> amiodarone

=> flecainide (if no structural heart disease)

=> others (less commonly used in UK): quinidine, dofetilide, ibutilide, propafenone

Less effective agents
beta-blockers (including sotalol)
=> calcium channel blockers
=> digoxin
=> disopyramide
=> procainamide
17
Q

AF: Cardioversion

Two reasons to use cardioversion:

  1. Electrical cardioversion as an emergency if the patient is haemodynamically unstable
  2. Electrical or pharmacological cardioversion as an elective procedure where a rhythm control strategy is preferred.
A

Onset <48 hours:

If the AF is less than 48 hours onset patients should be heparinised. Patients who have risk factors for ischaemic stroke should be put on lifelong oral anticoagulation. Otherwise, patients may be cardioverted using either:

i) electrical - ‘DC cardioversion’
ii) pharmacology - amiodarone if structural heart disease, flecainide or amiodarone in those without structural heart disease

Following electrical cardioversion if AF is confirmed as being less than 48 hours duration then further anticoagulation is unnecessary

Onset >48 hours:

If the patient has been in AF for more than 48 hours then anticoagulation should be given for at least 3 weeks prior to cardioversion.

Alternatively, perform a transoesophageal echo (TOE) to exclude a left atrial appendage (LAA) thrombus. If excluded patients may be heparinised and cardioverted immediately.

NICE recommend electrical cardioversion in >48 h, rather than pharmacological.

If there is a high risk of cardioversion failure (e.g. previous failure or AF recurrence) then it is recommend to have at least 4 weeks amiodarone or sotalol prior to electrical cardioversion

Following electrical cardioversion patients should be anticoagulated for at least 4 weeks. After this time decisions about anticoagulation should be taken on an individual basis depending on the risk of recurrence

18
Q

AF: Anti-coagulation

The following group should be considered for anti-coagulation if with a history of AF:
i) symptomatic or asymptomatic paroxysmal, persistent or permanent AF

ii) atrial flutter
iii) a continuing risk of arrhythmia recurrence after cardioversion back to sinus rhythm or catheter ablation

What is the CHA2DS2-VASc score and how does it determine the anticoagulation strategy?

A

C : Congestive HF : 1 pt

H : HTN (un/treated) : 1 pt

A2 : Age > 75 years : 2 pt
Age 65-74 years : 1 pt

D : Diabetes : 1 pt

S2 : Prior stroke, TIA, thromboembolism : 2 pt

V : Vascular disease i.e. IHD, PAD : 1 pt

S : Sex female : 1 pt

CHAD2S2-VASc score:
i) 0 = no treatment

ii) 1 = Males: consider anticoagulation
Females: No treatment (score of 1 due to gender)

iii) 2 or more = anti-coagulation
* Remember that if a CHA2DS2-VASc score suggests no need for anticoagulation it is important to ensure a transthoracic echocardiogram has been done to exclude valvular heart disease, which in combination with AF is an absolute indication for anticoagulation.

19
Q

AF: Assessing bleeding risk

How is ORBIT scoring system used to assess the risk of bleeding with anti-coagulation?

*HAS-BLED is now outdated

A

ORBIT SCORE has 5 components:

  1. Haemoglobin <130 for males ; <120 for females
    OR
    Haemtocrit <40% for males ;
    under 36% for females = 2 pt
  2. Age >74 years = 1 pt
  3. Bleeding hx inc. GI bleed, intracranial bleed or haemorrhagic stroke = 2 pt
  4. Renal impairment (GFR <60) = 1 pt
  5. Treatment with anti-platelet = 1 pt

ORBIT SCORE:

i) 0-2 => low risk
ii) 3 => medium risk
iii) 4-7 => high risk

20
Q

AF: which anti-coagulation therapy is indicated?

A 
DOACS recommended in AF in reducing stroke risk:
=> apixaban 
=> dabigatran
=> edoxaban 
=> rivaroxaban

Warfarin is used second line, if DOAC is contraindicated or not tolerated

Aspirin is not used at all.

21
Q

How should a patient with AF be followed up?

A
  1. Within 1 week of starting rate-control treatment or any dose alteration
    => check patient is tolerating the drug
    => review symptoms of AF i.e. palpitations, breathlessness and fatigue
    => review heart rate and BP
  2. If symptoms are not controlled by combination treatment, refer within 4 weeks to cardiologist
  3. Reassess CHAD2S2VASc score and ORBIT score at least annually
    => continue even if AF controlled
    => monitor DOAC at the start of treatment with baseline, 1 month into starting treatment and every 3-6 months after

Warfarin:
=> monitor warfarin daily until INR between 2 and 3 (therapeutic range) on 2 consecutive occasions.
=> then monitor twice weekly for 1-2 weeks
=> once stable, monitor every 3 months

CCC (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions