What to Know Now About Atrial Fibrillation

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By Mary Carpenter

PERIODS of rapid heartbeats had occurred only a few times for DMV-based writer K.M., but she worried about life-threatening atrial fibrillation (AFib), an electrical disorder of the heart.   According to University of Michigan (UM) Health, risk of stroke is three times higher in people with AFib, and their strokes are generally more severe—compared to people without the condition. Still, a highly recommended cardiologist dismissed K.M.’s concerns—even with her red flag family history: two brothers with recent strokes, one of those sudden and lethal.

“AFib is really pretty much an epidemic,” according to electrophysiologist Andrew Rubin at Eisenhower Health in Rancho Mirage, California. “Its incidence is expected to more than double over the next 15 years.” Advancing age increases risk for both AFib and for high blood pressure, which alone accounts for about one in five cases of AFib. And recently developed devices—one that monitors heartbeats and the other that both monitors and treats AFib—have brought renewed attention to the condition.

But symptoms of AFib can be silent—the reason that the 10% reported incidence in over-65-year-olds might be a vast underestimation. And that makes family history, especially involving stroke, an even more crucial diagnostic tool—notably for people such as K.M., who have normal-range scores on other assessments: LDL cholesterol levels, the heart-risk calculator, electrocardiogram (ECG) and exercise stress testing, and coronary artery (CAC) testing for plaque buildup in the arteries.

A fluttering sensation in the chest indicates an irregular heartbeat, or arrhythmia—the most common sign of AFib—a feeling that your heart is beating too hard or faster than normal, over 100 beats/minute. Rapid heartbeat, or tachycardia, is most worrisome when it occurs along with other symptoms such as chest pain, shortness of breath and feeling dizzy or faint. In addition to heart issues, common flutter generators can include exercise, anxiety, fever, dehydration, overactive thyroid and sleep apnea.

Heart problems arise when electrical signals that initiate the heartbeat come from somewhere other than the heart. Normally, electrical signals from cells in the heart, called the sinoatrial (SA) node, trigger the heart’s chambers (upper atria and lower ventricles) to move blood through the heart and out into the body, according to Cedars-Sinai. But electrical signals from outside the heart can cause “the atria to quiver (fibrillate) and [make the ventricles unable] to pump blood efficiently to the body.”

“The quivering atria can lead to blood pooling in the heart because [it] is not pumped efficiently from chamber to chamber,” according to the site. As a result, dangerous blood clots can form inside the heart, and temporarily reduced blood flow to the brain can cause fainting.   Paroxysmal AFib refers to arrhythmia that continues, either on and off or without stopping, for less than a week and usually is not treated.

But persistent AFib occurs for a week or longer and requires medical attention. In the past, the first step for someone experiencing persistent AFib has been to wear a somewhat clumsy heart monitor for a week or two. Others prefer using a smart-watch heart rhythm app—although one study on the Apple watch found it detected abnormal heart beats only about one third of the time.

In K.M.’s case, a cardiac electrophysiologist— specialist in heart rhythms—paid attention to her family history and recommended the Implantable Loop Recorder (ILR), a recent monitoring device. The ILR, which is placed under the skin overlying the heart in a minor surgical procedure, can store heart rhythm recordings for up to three years to help diagnose the problem.

For someone who experiences fainting, the ILR tracks heart rhythms from before, during and after the sudden drop in blood pressure that reduces blood flow to the brain—to help detect whether AFib is the cause. Fainting can occur with a variety of heart conditions and for other reasons, such as a stressful event triggering a vasovagal reaction that reduces blood flow to the brain by temporarily slowing the heart.

Lake Tahoe-based nurse and medical writer L.D., who had also received healthy heart assessment scores, described an unusual symptom: feelings of fullness in her chest and pressure in her neck that usually arose about half an hour after she plunged into the icy lake or snowshoed up to a high mountain ridge. But one day after a treadmill test—on which she performed well with the incline set as high as she could manage—as she sat recovering, she requested another measurement, which detected serious arrhythmia.

Another recent AFib implantable device, the Watchman, monitors heartbeats and can then provide stroke-prevention treatment. But because the device requires invasive surgery to implant via an artery in the groin, its best candidates are those with a diagnosis of persistent AFib. According to UM Health, for patients whose AFib is an electrical issue that alters the heartbeat—and not related to mitral valve problems —95% of stroke-causing clots are formed in an appendage to the heart’s left atrial artery, which the Watchman can seal off.

A traditional implantable AFib treatment is the cardiac defibrillator, which can detect arrhythmia and shock the heart back into regular rhythm. In addition, an electrical shock performed under sedation can reset heart rhythms. Another option is surgical ablation, which scars the heart tissue to make the beat more regular—but in some cases fails to stop AFib.   After two ablations, Lake Tahoe nurse L.D.’s heartbeats returned to normal.

Finally, medical treatment for AFib includes blood thinners, although they have a high risk for bleeding, and beta blockers that slow the heartbeat to control arrhythmia—which also helps people who have problems speaking to large groups. For me, past experiences with dry mouth that made it hard to talk, along with occasional shortness of breath and dizziness, led to anxious anticipation before speaking dates—surely contributing to my difficulties, and seeming miraculously to disappear with beta blockers.

—Mary Carpenter regularly reports on topical subjects in health and medicine.