Lyme disease can go on to cause heart and other complications, but preventing tick bites and early treatment of infection can reduce those risks.

Earlier this month, a woman in Vermont died of a rare complication of Lyme disease that affected her heart.

The condition is so uncommon that it’s the first reported death from Lyme carditis in the state, according to the Associated Press.

While any problems with the heart — fatal or otherwise — are concerning, experts say that people shouldn’t be overly alarmed about this condition, even people who live in tick-heavy states such as Vermont.

“There are hundreds of thousands of cases of Lyme disease every year, whereas the incidence for Lyme carditis is a single-digit percentage of that total number. So it’s a pretty small number,” said Dr. John Aucott, an associate professor of medicine at the Johns Hopkins University School of Medicine and director of the Johns Hopkins Lyme Disease Clinical Research Center.

Lyme carditis occurs when the bacterium that causes Lyme disease — Borrelia burgdorferi — migrates to the heart.

Once there, it interrupts the flow of electrical signals from the heart’s upper chambers (atria) to its lower chambers (ventricles).

This interferes with the ability of the atria and ventricles to coordinate their beating, resulting in the ventricles beating at a slower pace.

Also known as a “heart block,” this cardiac condition varies from mild to severe. When caused by Lyme disease, it can progress quickly.

“The main manifestation of Lyme carditis is it affects the electrical system of the heart,” said Aucott. “So it slows the heart rate down. If the heart rate slows down enough, you can actually pass out.”

Symptoms of Lyme carditis include light-headedness, fainting, heart palpitations, chest pain, and shortness of breath.

The Centers for Disease Control and Prevention (CDC) report that between 2001 and 2016, only 1 percent of confirmed Lyme disease cases in the United States involved carditis.

Also, between 1985 and 2018, only nine deaths resulting from Lyme carditis were reported in the medical literature.

Aucott says some of these deaths are due to people passing out while driving, causing them to crash their vehicle. Earlier detection of Lyme disease could have saved their lives.

“If you look at those cases, the issue was that their Lyme disease didn’t get diagnosed and treated,” said Aucott. “If it had been, they probably never would have gotten carditis.”

Treatment for Lyme carditis usually involves 14 to 21 days of antibiotics.

Symptoms disappear within one to six weeks, according to the CDC.

While carditis is treatable, Aucott said the more important public health issue is trying to recognize and treat Lyme disease earlier before complications like carditis occur.

“The first stage of Lyme disease is the acute stage — the rash or the flu-like symptoms,” Aucott told Healthline. “If that’s not treated, then you’re at risk of getting carditis several weeks to months later.”

Carditis occurs during stage 2, or early disseminated Lyme disease. During this stage, the bacteria can also invade the nervous system, causing meningitis and other neurological complications.

In stage 3, which occurs months or years after infection, bacteria have moved throughout the body. People in this stage show signs of chronic arthritis as well as worsening neurological symptoms.

Knowing the symptoms of early-stage Lyme disease can help prevent later complications. These include flu-like fever and body aches, and the characteristic erythema migrans rash.

People often think that the Lyme rash always has a target or “bull’s-eye” appearance. But only about 20 percent of rashes look like this, said Aucott. The rest are uniformly red or reddish-blue.

“The lesion that occurs with Lyme disease is very characteristic,” said Aucott. “But the rash doesn’t always look like a target, so people miss the opportunity to get an early diagnosis.”

One thing that distinguishes a Lyme rash from a mosquito bite or another type of rash is the way it grows in size — reaching more than 2 inches in diameter, and often up to 6 or 8 inches.

People can also reduce their risk of Lyme disease and its complications by avoiding being bitten by a tick in the first place.

In the United States Lyme disease is spread by black-legged ticks (also known as deer ticks) and western black-legged ticks. These ticks are found in the eastern and western parts of the country.

For tips and videos on how to prevent tick bites and what to do if you are bitten by a tick, check out the Johns Hopkins Lyme Disease Clinical Research Center.