Atrial fibrillation vs. atrial flutter: understanding the case of Senator Dick Durbin

Dick Durbin

Sen. Dick Durbin. Photo courtesy of the Center for American Progress Action Fund

Sen. Dick Durbin’s office announced yesterday the senator underwent a catheter ablation procedure to treat an abnormal heart rhythm known as atrial flutter. The condition is known to produce similar symptoms to atrial fibrillation, or AFib, which is the most common arrhythmia leading to hospitalization in the United States.

We asked Roderick Tung, MD, associate professor of medicine and medical director of the Center for Arrhythmia Care at the University of Chicago Medicine’s Heart and Vascular Center, about atrial flutter.

Science Life: What is atrial flutter?

Roderick Tung: Atrial flutter results from a ‘short-circuiting’ of the normal impulse in a loop that revolves around the top right chamber of the heart. Fortunately, atrial flutter is one of the most curable rhythms in our field as the circuit typically runs in a predictable loop in the atrium, like a racetrack.

How is atrial flutter different from atrial fibrillation?

In contrast to atrial flutter, atrial fibrillation is a more chaotic rhythm that does not follow one set loop. When the heart’s chamber fibrillates, it quivers or shakes, rather than contracting. This may produce similar symptoms to atrial flutter.

Many patients have both conditions as one rhythm can transition into another. In atrial flutter, the heart’s top chamber does not empty effectively and is out of sync with the contraction of the main pumping chamber of the heart. The presence of this rapid rhythm, which typically conducts every two to three times down the lower chamber, increases the risk for developing a blood clot in the heart and consequently increases a patient’s risk for stroke.

How are the flutter arrhythmias treated?

Some patients are asymptomatic, while others experience palpitations, lightheadedness or even heart failure. Patients are typically treated with either medications that slow the transmission of the short circuit to the lower chambers or with anti-arrhythmic medications that attempt to keep the heart in rhythm after an electrical cardioversion (a controlled electrical shock performed under sedation that resets the heart back to normal sinus rhythm).

Are atrial flutters curable?

Catheter ablation cures more than 90 percent of cases. During the procedure, thin electrodes are threaded up the large veins in the leg and positioned in the heart. Through these electrodes, physicians stimulate the heart and induce abnormal heart rhythms. Once they are able to locate the abnormal electrical tissue responsible for these arrhythmias, they deliver radio frequency energy or heat to destroy the electrical cells.

The creation of a line by radio frequency cauterization interrupts and unhinges this ‘racetrack loop,’ which permanently blocks this reentrant arrhythmia. This arrhythmia is one of the best understood mechanisms in human electrophysiology, in contrast to its cousin atrial fibrillation, which is the most commonly sustained arrhythmia in adults.

How is treating Afib similar to atrial flutter?

Similar to the treatment of atrial flutter, medications and ablation are most effective in treating fibrillation. Ablation is also effective in 60 to 70 percent of AFib patients. Current research seeks to understand the mechanisms of atrial fibrillation, which appear to come from multiple areas at the same time.

At the University of Chicago Medicine, doctors use special catheters that allow them to know how much force is being applied onto the tissue, which has been shown to improve the success rate for the procedure.  The location is one of only a handful of centers in the United States that uses a mapping system called ‘Rhythmia’, which allows physicians to create a 3-D reconstruction of the heart and customize the procedure for each patient.

About Kat Carlton (22 Articles)
Media Relations Specialist with the University of Chicago Medicine & Biological Sciences Division
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