We have all heard and used the idioms “my heart is racing”and “my heart missed a beat”. However, they are not just figures of speech. They happen literally – with a condition called atrial fibrillation or AF for short.
The general term for irregular heartbeat is arrhythmia and AF is the most common form of arrhythmia in the United States, according to a recent review in the ScienceDaily. A normal adult heart at rest beats around 50 to 100 beats per minute. A heart with AF beats much faster and very irregularly, making it “race” and “miss a beat.”
According to Eric Good, an AF specialist and assistant professor of cardiovascular medicine at the University of Michigan Medical School, “atrial fibrillation is a chaotic, electrical rhythm that begins in the top chamber of the heart, called the atrium…It involves impulses that whirl around the top chamber, traveling at speeds of 400 to 600 beats per minute in a type of electrical storm that can bombard the lower chambers with rapid signals and result in a very irregular and fast heart beat.“
What makes AF dangerous is that they act like “lightning bolts” in the heart to cause blood clots. These clots can be carried away by the blood, escape from the heart and get lodged in some blood vessels. Clots which block blood vessels to the brain can lead to stroke.
In the US, one in every 5 strokes is due to AF and the numbers are increasing.
“The link between [AF] and stroke is so tight that it is crucial that patients work with their doctor to discuss the treatment options,” according to Lewis Morgenstern, director of the University of Michigan Stroke Program. “There is a lot that can be done, particularly at a center such as ours with specially trained stroke specialists from neurology, cardiology and many other fields.”
In order to avert stroke, the irregular heart pattern needs to be corrected. Several treatments are available to control AF, from blood-thinning medications to avoid blood clots to pacemakers to radiofrequency (RF) ablation.
In RF ablation, catheters are inserted via the veins in the groins to the left atrium of the heart. Through the catheter, the heart is “zapped” to restore the heart rhythm back to normal.
New investigative devices to control AF are currently being tested at the University of Michigan Medical School and are described below.
The Watchman device is “designed to keep clots from forming in a small area of the heart that’s called the left atrial appendage – a “sock” off to the side of the atrium. The appendage seems to serve little purpose, and yet it’s the birthplace of more than 90 percent of clots that form in the heart.” It is inserted via a catheter like RF ablation.
Another device is a special balloon-camera that “looks” inside the heart and with a minute laser, it zaps the heart muscle. Like RF ablation, this zapping creates small scars on the muscles that stop the chaotic impulses from getting through.