Atrial Flutter

Atrial flutter is a heart rhythm disorder that starts in the atria, the upper chambers of the heart. In this condition, an electrical signal keeps circling around one large loop in the atria, so the atria beat very fast, about 250 to 350 times per minute. The AV node, the electrical gateway to the ventricles, filters out some of these signals. As a result, the ventricles usually beat more slowly, often around 150 times per minute, and the rhythm is regular.

Typical and Atypical Flutter

In typical flutter, the signal circles in the right atrium around the tricuspid valve and passes through a narrow strip of tissue called the cavotricuspid isthmus. This strip is the target of ablation. Atypical flutter uses other pathways, often around scar tissue after heart surgery or atrial fibrillation ablation, and mapping it is more complex.

How It Relates to Atrial Fibrillation

Atrial flutter is different from atrial fibrillation, in which the signals are chaotic so the heartbeat is irregular. However, the two often occur in the same person, and many people with flutter later develop atrial fibrillation as well. Stroke risk in flutter is assessed in the same way as in atrial fibrillation, covered on the Atrial Fibrillation page.

Who Gets It

Atrial flutter is more common in men and older adults. It often occurs alongside hypertension, heart failure, valve disease, chronic obstructive pulmonary disease, sleep apnea, or a history of heart surgery. An overactive thyroid gland and heavy drinking can also trigger it. Some people feel palpitations, tiredness, or shortness of breath; others feel nothing at all. Because the ventricular rate often stays around 150 beats per minute, the heart works hard continuously. If this lasts for weeks, the heart muscle can weaken, a condition that usually improves once the heart rate is controlled.

Treatment of atrial flutter aims to prevent stroke, control the heart rate, and restore a normal rhythm. In recurrent typical flutter, catheter ablation of the cavotricuspid isthmus can prevent flutter from returning over the long term, so it is often recommended early. The choice of medication, cardioversion, or ablation is made together with your doctor based on your symptoms, other conditions, and stroke risk.

The diagnosis can usually be made with an ECG. In typical flutter, the atrial waves look like evenly lined-up saw teeth, especially in the leads that view the bottom of the heart. If the heart rate is so fast that these waves are hidden, the doctor can slow it down temporarily so the pattern becomes visible. If flutter comes and goes, a Holter monitor or long-term recorder helps capture it.

Echocardiography assesses the size of the atria, the valves, and pumping strength. Before cardioversion, the doctor may perform echocardiography through the esophagus (transesophageal echocardiography) to make sure there are no clots in the atria. Blood tests check thyroid function, electrolytes, and kidney function to choose safe medications. The doctor also calculates a stroke risk score, the same as in atrial fibrillation. An electrophysiology study is done to confirm the signal pathway, usually at the same time as ablation.

Make an appointment with your doctor if you feel a fast, regular heartbeat, tire easily, or have unusual shortness of breath, especially if you are older or have heart or lung disease. Early treatment helps prevent stroke and weakening of the heart. Go to the emergency room right away if warning signs appear.

• A fast heartbeat that keeps coming back or lasts for hours
• A resting pulse of about 150 beats per minute or more
• Worsening tiredness, shortness of breath, or leg swelling
• Palpitations again after ablation or cardioversion
• A drooping face, weakness in one arm, slurred speech, fainting, or severe chest pain: go to the emergency room right away