Atrial flutter (A-Flutter) is a common supraventricular arrhythmia that, like atrial fibrillation (A-Fib), originates from abnormal electrical activity in the atria. However, unlike A-Fib’s chaotic impulses, atrial flutter has a more organized reentrant rhythm, resulting in regular atrial contractions at a rapid rate.
The hallmark feature on an EKG is the “sawtooth” pattern of flutter waves, making A-Flutter relatively easier to recognize compared to A-Fib. Understanding this arrhythmia is vital, as it carries risks of stroke, heart failure, and sudden deterioration into atrial fibrillation or more severe arrhythmias.
What is Atrial Flutter?
In A-Flutter, a reentrant circuit is established within the atria, causing them to contract at very high rates (250–350 bpm). The atrioventricular (AV) node cannot conduct all these impulses, so the ventricles typically contract at a slower but still rapid rate (e.g., 150 bpm if every second atrial impulse is conducted).
This results in a rhythm that is faster than normal sinus rhythm but more regular than atrial fibrillation.
Key Point: While atrial fibrillation is irregularly irregular, atrial flutter is usually regular with a sawtooth baseline.
EKG Features of Atrial Flutter
- Rate: 75–150 bpm (ventricular rate)
- Rhythm: Usually regular
- P waves: Absent; replaced by flutter (“F”) waves with a sawtooth appearance
- PR interval: Not measurable
- QRS complex: Usually normal and upright
Diagnostic Clue: The sawtooth pattern, especially visible in leads II, III, and aVF.
Causes of Atrial Flutter
Atrial flutter shares risk factors with other atrial arrhythmias:
1. Cardiac causes
- Coronary artery disease (CAD)
- Hypertension
- Heart failure
- Valvular disease (mitral stenosis/regurgitation, tricuspid disease)
- Cardiomyopathy
2. Systemic causes
- Hyperthyroidism
- Chronic lung disease (e.g., COPD)
- Pulmonary embolism
- After open-heart surgery, atrial scarring can predispose to flutter
Clinical Manifestations
Some patients may remain asymptomatic, while others experience significant symptoms due to reduced cardiac output.
- Fatigue and weakness
- Syncope (fainting)
- Palpitations (rapid pounding heartbeat)
- Chest pain or discomfort
- Shortness of breath
- Low blood pressure
Symptoms are usually due to decreased ventricular filling time and reduced cardiac efficiency, as well as pooling of blood in the atria.
Complications of Atrial Flutter
Like atrial fibrillation, atrial flutter carries a high risk of clot formation and embolization.
- Stroke (due to atrial thrombi traveling to cerebral circulation)
- Pulmonary embolism (PE)
- Myocardial infarction (MI) from coronary embolism
- Heart failure (from persistent tachyarrhythmia)
Risk for Clots: The atria quiver inefficiently, leading to pooling of blood → clot formation → embolic events.
Treatment of Atrial Flutter
Management depends on patient stability and includes rate control, rhythm control, and anticoagulation.
Stable Patient
Drug therapy:
- Calcium channel blockers (e.g., Diltiazem, Verapamil)
- Antiarrhythmics (Amiodarone, Flecainide, Sotalol)
- Anticoagulants (Warfarin, Apixaban, Rivaroxaban, Dabigatran) to prevent stroke
Unstable Patient (hypotension, severe chest pain, shock)
- Synchronized cardioversion (shock delivered in sync with QRS wave)
- This is highly effective in restoring sinus rhythm
Important Distinction:
- Cardioversion = synchronized shock (used in unstable atrial flutter or fibrillation)
- Defibrillation = unsynchronized shock (used only in pulseless, deadly rhythms like V-Fib or pulseless V-Tach)
Long-Term Management
Catheter ablation: Definitive therapy; ablates the reentrant circuit and prevents recurrence- Control hypertension, heart failure, and thyroid disease
- Avoid stimulants (alcohol, caffeine)
- Weight management and exercise
Comparative Overview: A-Flutter vs A-Fib
| Feature | Atrial Flutter (A-Flutter) | Atrial Fibrillation (A-Fib) |
|---|---|---|
| Origin | Reentrant circuit in atria | Multiple chaotic atrial foci |
| Rhythm | Usually regular | Irregularly irregular |
| EKG hallmark | Sawtooth flutter waves | No P waves, fibrillatory waves |
| Rate | 75–150 bpm (ventricular) | >100 bpm (usually) |
| Complication risk | High (stroke, clots) | High (stroke, clots) |
| Treatment | Rate control, cardioversion, ablation | Rate control, cardioversion, ablation |
Frequently Asked Questions (FAQ)
Q1. Is atrial flutter more dangerous than atrial fibrillation?
Both carry similar risks, especially for stroke. However, A-Flutter often responds better to treatment like cardioversion or ablation.
Q2. Can atrial flutter convert to atrial fibrillation?
Yes. Many patients alternate between A-Flutter and A-Fib, as both arise from atrial electrical disturbances.
Q3. What is the best long-term treatment for atrial flutter?
Catheter ablation offers the highest success rate for long-term rhythm control.
Q4. Do all patients with atrial flutter need anticoagulation?
Yes, unless contraindicated. Stroke risk is significant, and anticoagulation is crucial.
Q5. Can lifestyle changes alone cure atrial flutter?
No, but controlling risk factors (hypertension, obesity, thyroid disease, alcohol intake) helps reduce recurrence and severity.
