Atrial fibrillation: diagnosis and treatment updates
Most people with symptoms consistent with new-onset atrial fibrillation will not have hemodynamic disturbances, however, urgent referral to intensive care may be necessary to reduce the heart rate.
In people diagnosed with atrial fibrillation, there are two separates but equally important issues that must be considered:
- Symptom management.
Assess and manage the risk of thromboembolism.
A step-by-step management approach should be applied:
1. Confirm the diagnosis on the electrocardiogram.
2. Consider urgent referral for treatment.
3. Determine the type of atrial fibrillation (eg, persistent, paroxysmal, or permanent).
4. Symptom management.
5. Assess stroke risk to determine if antithrombotic therapy is needed.
Determine the presence of the following symptoms:
Shortness of breath.
Dizziness, fainting, or fainting.
Weakness or fatigue.
Determine if symptoms associated with atrial fibrillation (or treatment of atrial fibrillation) are affecting the patient's function (subjective quality of life).
Symptoms associated with atrial fibrillation have minimal effect on the patient's overall quality of life
There are no symptoms associated with atrial fibrillation.
Minimal and/or infrequent symptoms; or an episode of atrial fibrillation without syncope or heart failure.
Symptoms associated with atrial fibrillation have little effect on the patient's overall quality of life
Mild cognitive impairment of symptoms in patients with persistent/permanent atrial fibrillation; or;
Episodes are rare (eg, fewer than a few per year) in patients with paroxysmal or intermittent atrial fibrillation.
Symptoms associated with atrial fibrillation have a moderate effect on the patient's overall quality of life
Moderate cognitive impairment of symptoms on most days in patients with persistent/permanent atrial fibrillation; or;
More frequent episodes (eg, more than every few months) or more severe symptoms, or;
Both, in patients with paroxysmal or intermittent atrial fibrillation.
Symptoms associated with atrial fibrillation have a serious impact on the patient's overall quality of life
Very unpleasant symptoms in patients with persistent/paroxysmal atrial fibrillation; and/or;
Frequent and severe episodes in patients with paroxysmal or intermittent atrial fibrillation.
And/or syncope attributed to atrial fibrillation; and/or congestive heart failure secondary to atrial fibrillation
Start emergency treatment
Consider referral to the emergency department or start emergency management if multiple symptoms are present.
Most people with symptoms consistent with new-onset atrial fibrillation will not have hemodynamic compromise, however, urgent referral to intensive care may be necessary to reduce the heart rate if the patient:
Heart rate > 150 beats per minute or systolic blood pressure < 90 mmHg.
Chest pain, increasing dyspnoea, severe dizziness, or loss of consciousness (including patients with acute ischemia, ECG changes).
Any complication of atrial fibrillation such as a transient ischemic attack, stroke, acute ischemia, or acute heart failure.
Consultation with a cardiologist
Paroxysmal atrial fibrillation may occur (as this requires medications not normally taken in primary care such as amiodarone or sotalol).
ECG abnormalities such as Wolff-Parkinson-White syndrome or prolonged QT interval.
Known or suspected valvular disease.
Symptoms persist despite appropriate rate control therapy.
Determine the type of atrial fibrillation
Paroxysmal AF - characterized by recurrent episodes of atrial fibrillation that last less than seven days (although often less than 24 hours) and resolve spontaneously within that time. Rhythm control is the preferred treatment.
Persistent AF - characterized by episodes of atrial fibrillation that last more than seven days and do not resolve on their own during this time. Treatment is speed or rhythm control depending on the individual patient's condition.
Permanent AF - atrial fibrillation has been present for more than a year and cardioversion has failed. Rate control takes precedence.
In the absence of contraindications, appoint heparin at first appearance.
Enoxaparin 1 mg/kg x 2 times/day.
Control heart rate if no severe symptoms
The choice between rate or rhythm control is guided by the type of atrial fibrillation and other factors such as age, presence of comorbidities, presence or absence of symptoms, and patient preference.
Control of the atrioventricular rate is recommended for most patients. It should be given special consideration to patients who
Atrial fibrillation is asymptomatic.
Permanent atrial fibrillation.
Rate control for a particular patient can be discussed with a cardiologist.
Rhythm control, aimed at restoring and maintaining sinus rhythm, should be considered for patients who
Paroxysmal atrial fibrillation.
Persistent atrial fibrillation and ongoing symptoms, any hemodynamic effects, failure of rate control, or persistent symptoms despite rate control.
Structural heart disease, eg. severe left ventricular dysfunction or hypertrophic cardiomyopathy (atrial fibrillation is often not well tolerated in these patients).
All patients who contemplated a rhythm control strategy should be referred to a cardiologist.
Assess thromboembolic and stroke risk to determine appropriate antithrombotic therapy
Congestive heart failure/left ventricular dysfunction (1).
Age ≥ 75 years old (2).
Stroke/transient ischemic stroke (2).
Vascular disease (old myocardial infarction, peripheral vascular disease) (1).
Age 65–75 years old (1).
Female gender (1).
Maximum score (9).
The maximum score is 9 because age is allocated one or two points
If the CHADS2 score is ≥ 2, the patient should be anticoagulated. If the patient has a CHA2DS2-VASc score lower than 2, it can be used to further assess risk and guide treatment selection.
Indications for electric shock
Cardiac electric shock
If the patient's systolic blood pressure is unstable (less than 100 mm Hg, signs of hypoperfusion):
In atrial fibrillation. Synchronous heart rate switching at 200 J, 300 J and 360 J or equivalent biphasic.
In the frenzy. The synchronous beat starts at 50J.
Check the pulse and pulse between each attempt to convert the heart rate.
Consider sedation during cardioversion.
Heart rate greater than 150 and patient stable but symptomatic:
Initial dose: 0.25 mg/kg intravenously slowly over two (2) minutes.
If the response is inadequate after 15 minutes, re-inject 0.35 mg/kg IV slowly over two (2) minutes.
Contraindicated. Wolff-Parkinson-White syndrome, second- or third-degree atrioventricular block and sick sinus syndrome (except in the presence of a ventricular pacemaker), severe hypotension, or cardiogenic shock.
Incidence is less than 150 and patients are stable but symptomatic:
Amiodarone 150 mg slow IV/oral infusion over 10 minutes.
Metoprolol: maintenance: 25-100 mg orally every 12 hours.
Flecainide: 50 mg orally; do not exceed 300 mg/day.
Propafenone: 150 mg orally every 8 hours.