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Diagnosing Atrial Fibrillation & Atrial Flutter

Cardiac electrophysiologists at NYU Langone’s Heart Rhythm Center treat people who have atrial fibrillation (AFib) and atrial flutter. These are types of supraventricular arrhythmias caused by problems with the heart’s electrical system.

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VIDEO: Catherine, 31, came to the Heart Rhythm Center for catheter ablation treatment to correct her abnormal heart rhythms.

The heart is a pump that moves blood through your body. That pump is activated by the heart’s electrical system, which sends signals that control heart rate and rhythm.

If your heart is beating normally, it falls into a steady rhythm of 60 to 80 beats per minute in a consistent, coordinated rhythm, speeding up or slowing down in response to physical activity, strong emotions, or stress. With moderate exercise, the heart typically beats 90 to 115 times per minute.

AFib causes the heart to beat chaotically and too fast—as quickly as 600 beats per minute. The upper heart chambers fibrillate, or rapidly twitch and quiver. When the heart enters an AFib rhythm, blood does not flow properly into the heart’s ventricles, or lower chambers. This causes blood to pool, which can result in clots that can lead to a life-threatening stroke.

AFib can also limit blood flow throughout the body. This can lead to heart failure, a serious condition in which the heart does not pump enough blood to meet the needs of the rest of the body.

Atrial flutter causes a fast but regular heartbeat—sometimes as rapid as 350 beats per minute. Atrial flutter occurs when certain electrical signals do not reach the ventricles of the heart. Like AFib, this rapid heartbeat also increases the risk of developing blood clots and stroke. The condition can be temporary or ongoing.

Often, AFib and atrial flutter occur at the same time.

Symptoms of Atrial Fibrillation and Atrial Flutter

Some people with AFib or atrial flutter have no symptoms. When symptoms occur, they can range from mild to severe, depending on the heart’s ability to function and a person’s overall health.

Exercise is a common AFib trigger. Many people with the condition tire easily while exercising and experience pain or extreme fatigue afterward because the heart isn’t supplying enough oxygen-rich blood to the body’s other organs.

Other symptoms of AFib include heart palpitations, which are an irregular or rapid heartbeat that some say feels as if your heart is flip-flopping in your chest; a racing or pounding feeling in the chest; lightheadedness, dizziness, or fainting; sweating; shortness of breath; and chest pain or pressure. 

Symptoms of atrial flutter are similar to those of AFib. They include a fluttering feeling in the chest, heart palpitations, shortness of breath, lightheadedness, dizziness, fatigue, and difficulty exercising.

Diagnosing Atrial Fibrillation and Atrial Flutter

To diagnose AFib and atrial flutter, your electrophysiologist performs a physical exam, measures your heart rate using an electrocardiogram (EKG), checks your blood pressure, and asks about your family history. Your doctor may recommend additional laboratory tests, imaging tests, and noninvasive monitoring.

Tests used to diagnose and manage AFib and atrial flutter include the following.


An EKG is the most important test used in the diagnosis of AFib and atrial flutter. An EKG is performed by placing small, painless electrodes on your chest, wrist, and ankles. This test is performed while you are at rest or, in the case of an exercise stress test, while you are walking on a treadmill.

Our electrophysiologists have the experience and skill to identify subtle electrical readings in EKG test results. This leads to an accurate, reliable diagnosis and more effective treatment.

Imaging Tests

There are several imaging tests used to help in the treatment and management of AFib and atrial flutter. A transthoracic echocardiogram (TTE) is an ultrasound test that uses high-frequency sound waves to produce detailed images of the heart’s size, shape, and motion as it pumps blood. This test can also reveal blood clots, which can lead to stroke, and evaluate the heart’s ability to pump blood, called its ejection fraction. A low ejection fraction measurement may be a sign of heart failure.

In a transesophageal echocardiogram (TEE), an ultrasound probe is inserted through the mouth and into the esophagus. Because the probe is placed close to the heart, a TEE can provide clearer pictures of the heart’s chambers than a traditional echocardiogram. This test is used to rule out the presence of blood clots. TTE and TEE are often performed at the same time.

Advanced imaging, including MRI scan and CT scan, may be used to look for structural problems, scarring, or an injury in the heart that can lead to an arrhythmia.

Surveillance Monitoring

A surveillance monitor, including a Holter device, ambulatory telemetry device, or implantable cardiac loop recorder, may be recommended if you have intermittent and unpredictable episodes of arrhythmia.

A Holter device is a small, wearable surveillance device that is the size of a smartphone. It records changes in heart rhythm over a 24- or 48-hour period. Your doctor uses the test results to determine whether there is evidence of a heart rhythm disorder.

An ambulatory telemetry device is a lightweight, portable heart monitor that is worn for up to two weeks to measure your heart’s electrical activity for signs of a heart rhythm disorder. Test results are sent wirelessly to your doctor for review via a secure website.

An implantable cardiac loop recorder is a small device that’s placed under the skin of the chest to continuously monitor and record your heart rhythm for up to two years. This device is used in the Reveal LINQ™ Heart Failure study to monitor people who are at increased risk of stroke.

Our Research and Education in Atrial Fibrillation and Atrial Flutter

Learn more about our research and professional education opportunities.