Atrial fibrillation (Afib) affects millions of Americans from every walk of life. It 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 (paroxysmal Afib) or intermittent Afib (persistent Afib). Treatment is individualized, directed at addressing each patient’s specific needs.
During normal heart rhythm, every muscle cell in the upper chambers contracts at the same time. This 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 have a feeling of “not well being” 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 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.
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There are several ways to treat Afib:
- Normal heart rhythm can be restored using drugs or an electric shock. Many people revert back into atrial fibrillation, so this procedure alone is sometimes inadequate therapy.
- The therapy of rate control and anticoagulation 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). Though this is appropriate therapy for some, 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. 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 aberrant conduction pathways and restore normal rhythm. The success rate depends upon whether the Afib is continuous or intermittent.
- 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. Because the pulmonary veins are often the source of early beats that cause Afib, the veins are electrically isolated. 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.
For more information about your heart, visit your doctor.
The Society of Thoracic Surgeons: 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.