Atrial fibrillation, or AF, is a condition that affects the speed of rhythm of a person's heartbeat.

AF is the most common type of arrhythmia, or irregular heartbeat, affecting more than two million Americans. It's caused by a malfunction within the heart's electrical system. Rapid, disorganized electrical signals are sent through the heart's upper chambers, or atria. This causes the atria to contract wildly and collect pooled blood. As a result the blood that is pooled in the atria is not being pushed into the heart's lower chambers called the ventricles. When this happens the atria and ventricles aren’t able to work together as they should.

AF can cause chest pain, heart attack or heart failure and can lead to increased risk of stroke. About 15 percent of all strokes occur in AF patients.

Each heartbeat is initiated by an electrical signal that begins at the top of the heart and moves downward. Each signal originated in the sinoatrial node, or SA node, located near the right atrium. As the signal travels down the heart it triggers a contraction, pumping blood from one chamber to another.

The SA node produces an electrical signal an average of 60 to 100 times a minute in a healthy heart. In patients with AF, the electrical signal does not originate in the SA node, but rather in a different part of the atria. This makes it difficult for the signal to travel along the correct path causing rapid disorganized contractions.

There are an array of medications available to slow down the rapid heart rate associate with AF. If medication isn't effective, a procedure called electrical cardioversion may be used to shock the heart into producing a normal rhythm. Atrial pacemakers can also be implanted to keep the heart beating regularly.

Radiofrequency ablation may also be effective in regulating heartbeat. In this procedure, tubes are fed through a blood vessel and directed to the heart muscle. Then a burst of radiofrequency energy is delivered to destroy tissue that triggers abnormal electrical signals. Radiofrequency ablation can also be used to block abnormal electrical pathways.

The newest AF treatment on the horizon is a form of radiofrequency ablation. Its called high intensity focused ultrasound (HIFU) ablation system. HIFU is currently being tested in a clinical trial called focusAF.

Researchers are hopeful that this will be the last step before HIFU receives FDA approval.

During the procedure, controlled ablation lesions are made by the special HIFU catheter and are intended to prevent unwanted electrical impulses from being generated. An ultrasound is delivered to a very specific isolated region of the heart without disrupting surrounding tissue.

This is the first technique to treat AF that delivers energy bursts forward in a complete circle from outside a vein. A similar technique, utilizing high intensity focused ultrasound, is currently being used to treat certain cancers.

Additional Resource:

David Callans, M.D.