Atrial Flutter Flashcards
What is atrial flutter?
Atrial flutter (anti-clockwise cavotricuspid isthmus-dependent atrial flutter) is a macro-reentrant atrial tachycardia with atrial rates usually above 250 bpm up to 320 bpm. It results from organised electrical activity in which large areas of the atrium take part in the reentrant circuit.
The typical form depends on the so-called cavotricuspid isthmus for part of the circuit: tricuspid annulus as the anterior boundary and the crista terminalis/eustachian ridge as the posterior boundary, as well as the endocardial cavity of the right atrium. The term anti-clockwise refers to the direction of activation when the tricuspid annulus is viewed en face, whereby activation occurs up the septum, down the right atrial free wall in an anti-clockwise fashion.
What are the risk factors for atrial flutter?
- Surgical or post-ablation scarring of atria
- Increasing age
- Valvular dysfunction
- Chronic ventricular failure
- Atrial septal defects
- Atrial dilation
- Recent cardiac or thoracic procedures
- Heart failure
- Hyperthyroidism
- COPD
- Asthma
- Pneumonia
What is the most common presentation of atrial flutter?
Most characteristically 150 bpm, because an associated 2:1 atrioventricular block.
What are the symptoms of atrial flutter?
- May be asymptomatic
- Dyspnoea
- Palpitations
- Fatigue
- Syncope
- Poor exercise tolerance
What are the signs of atrial flutter?
- Tachycardia with regular pulse
- Symptoms of underlying disease (e.g. murmurs)
What investigations should be ordered for atrial flutter?
- ECG
- Thyroid function tests
- Serum electrolytes
- CXR
What ECG changes are seen in atrial flutter?
- In the typical form (anti-clockwise atrial flutter), negatively directed saw-tooth atrial deflections (f waves) in leads II, III, and aVF, and positive deflections in V1 with atrial rates of 240 to 320 bpm are seen.
Why investigate thyroid function tests? And what may this show?
- To rule out underlying thyroid disease.
- Normal or abnormal if underlying thyroid disease is present.
Why investigate serum electrolytes? And what may this show?
- Electrolyte abnormalities are generally not the sole cause of atrial flutter, but imbalances should be checked and corrected.
- Normal or abnormal if underlying electrolyte disturbances are present,
Why investigate using CXR? And what may this show?
- Should be ordered if there is clinical suspicion of lung disease as a cause.
- Normal or may be abnormal if underlying lung disease is present.
Describe the use of cardioversion in atrial flutter
- Haemodynamically unstable patients require urgent synchronised cardioversion.
- Haemodynamically stable patients can be treated with pharmacological therapy.
- Cardioversion (either electrical or pharmacological) is an option in patients who do not respond to rate-control drugs.
What drugs are used for rate control in atrial fibrillation?
Beta-blockers and calcium-channel blockers are used for rate control in atrial flutter:
- Beta-blockers: metaprolol or esmolol
- Calcium-channel blockers: diltiazem or verapamil
Why are calcium-channel blockers preferred for rate control in patients with atrial fluuter and chronic lung disease?
Beta-blockers might provoke bronchospasm.
What drugs are used for thromboembolic prophylaxis in atrial flutter?
- Heparin or enoxaparin plus warfarin should be initiated in all patients and the parenteral anticoagulant continued until the warfarin levels are therapeutic (INR 2-3).
- Direct oral anticoagulants (DOACs) such as dabigatran, apixaban, edoxaban, and rivaroxaban can be used as alternatives to heparin or enoxaparin plus warfarin.
Which patient group are direct oral anticoagulants (DOACs) cautioned in?
DOACs do not require monitoring of anticoagulant activity; however, they must be used with caution in patients with renal impairment and a dose adjustment may be necessary.
