September 5, 2019
Originally published October 21, 2016
Atrial fibrillation (Afib) affects millions of Americans from every walk of life. Afib is a problem with the pumping of the heart’s upper chambers (the atria). The chance of having Afib increases with age, and it can occur alone (lone Afib) or in combination with another cardiac problem (concomitant Afib), such as a leaking valve. People can be in continuous Afib (persistent Afib) or intermittent Afib (paroxysmal Afib). Treatment is individualized, directed at addressing each patient’s specific needs.
To have an effective pumping action, all the individual microscopic muscle cells of the chamber must contract at the same time. This is what happens during normal heart rhythm and results in the active pumping of blood from the upper chambers into the lower chambers (the ventricles). During Afib, muscle cells contract individually and randomly, causing a quivering atria with no active pumping of the atria. Within the atria, where the blood flows slowly and pools, blood clots can form.
Several problems are associated with Afib:
- Untreated, Afib can result in a very fast heart rate because electrical signals are constantly being passed to the lower chambers. Many people with a fast heart rate feel unwell and may have a vague sense of impending doom.
- When the lower pumping chambers are contracting very fast, they do not have enough time to fill with blood between each contraction, and thus the heart may not pump adequate amounts of blood. This can lead to being easily tired and a general lack of energy. The problem of a too rapid heartbeat causing inadequate filling of the lower chambers can be made worse by the loss of the contracting force of the upper chambers. When the atria are fibrillating, or quivering, the amount of blood the heart is pumping can be reduced by up to 40%.
- Afib can cause strokes. This is because when the atria are not contracting and blood pools, clots can form. Ninety percent of the time, these clots form in the atrial appendage (small, ear-shaped sac in the muscle wall of the atrium). If these clots break free, they can move to the brain, blocking blood flow and causing a stroke.
There are several ways to treat Afib:
- Normal heart rhythm can usually be restored using medication. Sometimes an electric shock may be necessary to reset normal rhythm. Even after these treatments, some people revert back into atrial fibrillation, and another treatment or procedure is required.
- There is another medication-based therapy called rate control and anticoagulation. It is not aimed at restoring normal rhythm. Its goal is to slow the heart rate with drug therapy and prevent strokes with blood thinners (usually warfarin). This is appropriate therapy for some patients. However, other people may continue to feel poorly on rate control and anticoagulation.
- The classic Maze operation is based on the fact that electric waves in the heart cannot cross scars. During the classic Maze, multiple scars are precisely placed in the upper chambers of the heart. Contraction waves then move through the “maze” in an organized, rather than chaotic, pattern. The scars may be thought of as channeling the flow of electricity. Although this operation is highly successful (around 95%), it involves opening the chest, placing the patient on the heart-lung machine, and stopping the heart. The Maze operation may be appropriate for people who have another cardiac problem that also requires operation, but it is less often appropriate for lone Afib.
- Another treatment for Afib is catheter ablation. Usually done by an electrophysiologist, a catheter is passed up to the heart from the leg. It enters the right atrium and moves into the left atrium through a puncture hole in the wall between the right and left atria. Then, under x-ray guidance, a series of burns are made on the left atrium to block abnormal conduction pathways and restore normal rhythm. The success rate depends upon whether the Afib is continuous or intermittent, but is lower than the Maze operation.
- A newer, less invasive surgical treatment for Afib is called totally thorascopic ablation. This operation is performed by a surgeon on the closed chest using endoscopes, ports, and small incisions between the ribs. Because the pulmonary veins are often the source of early beats that cause Afib, the veins are electrically isolated by placing a scar around them. If a patient has continuous Afib, additional lines of ablation are made. The left atrial appendage is the source of the blood clots that cause over 90% of the strokes, so it is closed off or removed. These techniques result in up to 86% cure rate for intermittent Afib.
- An even newer procedure being pioneered in a few centers is hybrid ablation. This procedure combines thorascopic ablation with catheter ablation.
Learn more about cardiac rhythm disturbances.
The opinions expressed in this article are those of the author and do not necessarily reflect the views of The Society of Thoracic Surgeons.
The STS mission is to advance cardiothoracic surgeons’ delivery of the highest quality patient care through collaboration, education, research, and advocacy.