A normal heartbeat has a predictable rhythm to it, a kind of pa-dum-pa-dum-pa-dum that’s slower when you’re resting and faster when you’re in motion. “If you listen, normally there may be some variation in the heart rate, but it will be nice and regular,” says electrophysiologist Burr Hall, MD, an associate professor of cardiology at the University of Rochester Medical Center in Rochester, N.Y. “In atrial fibrillation, it may sound almost like when your shoes are in the dryer, going all over the place.” Atrial fibrillation is a type of arrhythmia, which literally means “not rhythmic,” hence the somewhat random “shoes in the dryer” effect, which you can also feel in your pulse. Because these sounds are only audible to your doctor through a stethoscope and because they occur as a result of problems with your heart’s electrical signals that you can’t feel, going for regular checkups is important to good health.
The Heart’s Electricity
Although you probably don’t think of your heart as a machine, it does in fact run on electricity. At the top of your heart, a central spot called a sinus generates an electrical signal that runs down to the bottom of your heart. As this signal moves, it instructs the four chambers of the heart to contract; the atria are the top two chambers and the ventricles are the bottom two. The flow of each signal evenly stimulates your heart to contract, creating the sound of the normal heartbeat and pushing blood evenly throughout your body. In atrial fibrillation, however, this signaling process is disrupted. Instead of one signal managing the entire contraction of your heart muscle, there are multiple signals, and they may come from more than one place in your heart’s muscle. Though only a few of those signals make it all the way to the bottom of your heart, the result is still confusion and inconsistency. This results in the quivering or racing sensation that characterizes atrial fibrillation. Your doctor can hear it during an exam, and you can feel it if you know how to take your pulse. Besides the discomfort you might feel from the symptoms of atrial fibrillation, there is a real long-term risk for your health. The disrupted signaling that causes the uneven beating of your heart means that blood isn’t moving in and out of your heart correctly. This raises your risk for a stroke. “With the top chambers going so fast, patients are at risk for developing clots,” says Dr. Hall, who compares the lower levels of the heart to water in a stagnant pond. “The blood just sits and kind of quivers and allows blood clots to form,” she says.
A ‘Sound’ Diagnosis
How your heart sounds is just one part of making an atrial fibrillation diagnosis. The gold standard is the electrocardiogram (EKG). This is a test that measures the electrical activity of the heart, creating a graph of your heartbeat. Even though an afib heart can cause significant symptoms, such as a quivering heart sensation, dizziness, and chest discomfort, a significant number of people do not know they have atrial fibrillation. A study of 432 adults published in the journal Stroke found that of those who had atrial fibrillation, only about 60 percent were aware of it. If you’ve had some of the symptoms of atrial fibrillation, don’t try to hear an afib heartbeat on your own. Atrial fibrillation warrants a listen by your doctor.
