Atrial flutter (AFL) is a common abnormal heart rhythm that starts in the atrial chambers of the heart. When it first occurs, it is usually associated with a fast heart rate and is classified as a type of supraventricular tachycardia.
Atrial flutter is characterized by a sudden-onset (usually) regular abnormal heart rhythm on an electrocardiogram (ECG) in which the heart rate is fast.
Symptoms may include a feeling of the heart beating too fast, too hard, or skipping beats, chest discomfort, difficulty breathing, a feeling as if one’s stomach has dropped, a feeling of being light-headed, or loss of consciousness.
Although this abnormal heart rhythm typically occurs in individuals with cardiovascular disease (e.g. high blood pressure, coronary artery disease, and cardiomyopathy) and diabetes mellitus, it may occur spontaneously in people with otherwise normal hearts. It is typically not a stable rhythm, and often degenerates into atrial fibrillation (AF).
However, it does rarely persist for months to years. Similar to the abnormal heart rhythm atrial fibrillation, atrial flutter also leads to poor contraction of the atrial chambers of the heart. This leads to the pooling of the blood in the heart and can lead to the formation of blood clots in the heart which poses a significant risk of breaking off and traveling through the bloodstream resulting in strokes.
Signs and symptoms
Patients typically present with complaints of palpitations, fatigue, or mild dizziness.
In situations where the arrhythmia is unrecognized for a prolonged period of time, patients may present with symptoms and signs of heart failure (dyspnea, exertional intolerance, edema) due to tachycardia-induced cardiomyopathy.
The ECG typically demonstrates a “sawtooth” pattern of atrial activity in the inferior leads (II, III, and AVF). The reentrant circuit generates atrial rates of 250–350 beats/min, usually with transmission of every second, third, or fourth impulse through the AV node to the ventricles.
How is atrial flutter diagnosed?
Atrial flutter is normally diagnosed in your physician’s office using an electrocardiogram (ECG or EKG). If the diagnosis is still in question, your doctor may recommend a Holter monitor, an event monitor or an electrophysiological study, during which a narrow, flexible tube called a catheter is threaded through a vein to your heart under light sedation. Fine wires inside the catheter can help pinpoint the abnormal signal.
How is atrial flutter treated?
Sometimes, atrial flutter goes away by itself and no further action is needed. If it persists, your doctor may pursue any of the following treatments:
- Treatment of any underlying conditions
- Catheter ablation — procedure to destroy the errant electrical pathways; performed together with an electrophysiological study
- Cardioversion — small, controlled shock to the chest done under anesthesia to provide short-term correction of the heart rhythm
- Medications to control the heart rhythm, called antiarrhythmics, may be less effective than catheter ablation
- Medications to prevent blood clots