Atrial Flutter (Heart Flutter)

What is Atrial Flutter?

Atrial flutter is a common arrhythmia, or abnormal heart rhythm, that affects the upper chambers of the heart (atria). It happens when electrical signals travel through abnormal pathways (circuits), causing the atria to beat very fast, up to 300 times per minute.

Not all of these rapid beats reach the lower chambers (ventricles), but enough do to raise the heart rate to around 150 beats per minute, well above the normal 60–90 beats per minute.

Atrial flutter is generally classified as:

1. Typical atrial flutter: Usually arising from the right atrium
2. Atypical atrial flutter: Involves variable circuits and may originate from either atrium

Overlap with Atrial Fibrillation

While atrial flutter and atrial fibrillation (AF) can overlap, they are distinct conditions. A systematic review found that:

• More than 70% of people with atrial flutter do not experience atrial fibrillation, meaning AFL can occur on its own.
• Less than 10% of people with atrial fibrillation are also diagnosed with atrial flutter.
• Because AF is much more common than AFL, many people with AFL also have AF at some point.

This overlap matters for how doctors monitor and manage rhythm disorders, especially in people with heart failure.

Heart Flutter Causes & Risk Factors

Atrial flutter can affect people with or without prior heart problems. Common factors include:

• Heart conditions: Congestive heart failure, rheumatic or congenital heart disease, high blood pressure, or previous cardiac surgery
• Lung diseases: Such as emphysema
• Age: Risk increases with age
• Other arrhythmias: AFL can occur in people with atrial fibrillation or after AF treatment with anti-arrhythmic medications
• Lone AFL: Sometimes occurs in otherwise healthy hearts

Patient note: Risk factors do not guarantee AFL, but can help with early detection and improve management.

Symptoms of Atrial Flutter

Some people with atrial flutter may have no symptoms, while others experience a range of signs, particularly when their heart beats very fast:

• Palpitations: Feeling of rapid or irregular heartbeat
• Fatigue and shortness of breath
• Lightheadedness or dizziness
• Reduced exercise tolerance

In patients with very fast heart rates, more serious symptoms can occur:

• Low blood pressure (hypotension)
• Fainting (syncope) or near-fainting

Some patients remain symptom-free until complications develop, such as heart failure, tachycardia-induced heart muscle weakening, or stroke.

Physical signs a doctor may notice include:

• Irregular or rapid pulse
• Jugular vein swelling
• Crackling sounds in the lungs
• Swelling in the abdomen or legs

Complications of Atrial Flutter

Atrial flutter can lead to serious problems if untreated or poorly controlled:

• Stroke: Increased risk of blood clots, which can cause stroke and disability.
• Fast heartbeat: Can cause dizziness, shortness of breath, or heart strain.
• Heart function: Persistent AFL may weaken the heart, leading to heart muscle problems or heart failure.
• Medication risks: Anti-arrhythmic drugs can cause side effects depending on the type.

Diagnosis

An ECG (electrocardiogram) is often the first step in diagnosing this heart rhythm disorder. However, ECG findings alone cannot always determine the exact source of the abnormal rhythm.

Modern high-resolution electroanatomical mapping systems allow specialists to visualise the heart’s electrical activity in greater detail, helping them accurately locate the underlying circuit.

If you’re experiencing atrial flutter symptoms, a specialist assessment may help clarify your treatment options.  Book a consultation at The Keyhole Heart Clinic for expert support and personalised care.