HMN 2025: How Unusual heart rhythm disorder is surprisingly common in patients with long COVID

A new study from Karolinska Institutet shows that an unusual heart rhythm disorder, POTS, is particularly common in people with long COVID. The majority of those affected are middle-aged women. The study has been published in the journal Circulation: Arrhythmia and Electrophysiology.

Postural orthostatic tachycardia syndrome, or POTS, is a condition where the heart beats abnormally fast when changing position from lying down to standing up. Standing up is a challenge for those affected who feel dizzy and would rather sit or lie down, so-called orthostatic intolerance. Their hearts may also beat faster than normal at rest and during exertion. Patients experience fatigue and difficulties concentrating, symptoms that are common in long COVID.

Now, researchers at Karolinska Institutet show that POTS occurs in almost a third of patients with severe long COVID. By comparison, less than 1% of the Swedish population was affected by POTS before the pandemic.

“Previous, smaller studies have shown that there is a connection, but now we can say with certainty that POTS is a very common condition in patients with long COVID. This is valuable knowledge for both health care professionals and patients,” says Mikael Björnson, doctoral student at the Department of Medicine, Solna, Karolinska Institutet.

Women in their early middle age

According to the researchers, this study is the largest and most detailed to date on the link between POTS and long COVID. A total of 467 patients with severe long COVID who had not been hospitalized for COVID-19 were examined. Ninety-one percent were middle-aged women who were essentially healthy and physically active before they developed long COVID. At an average of 12 months after falling ill, they underwent physical tests and completed forms about their health. Those who showed signs of possible POTS also received an assessment from a cardiologist after further, targeted tests.

Thirty-one percent of participants received a POTS diagnosis, while 27% had symptoms but did not meet the criteria for diagnosis. The remaining 42% had no symptoms of POTS. Patients with a diagnosis had significantly higher heart rates during walking tests and reported lower health-related quality of life.

POTS can be treated

“It is important to know that POTS can be detected with inexpensive, simple tests that are available at all levels of health care. For those who receive a diagnosis, there are treatments that can alleviate symptoms and improve quality of life,” says Judith Bruchfeld, associate professor at Karolinska Institutet, senior consultant in infectious diseases at Karolinska University Hospital and head of the study.

The researchers now recommend that patients with long COVID who experience a significant increase in heart rate when changing position from lying down to standing, as well as during exertion, and who experience symptoms such as dizziness, brain fog and pronounced fatigue, are investigated for POTS.

The next step in the research is a four- and five-year follow-up of the patient group, and in addition, patients with COVID-19 who have been treated in hospital. The researchers will investigate recovery and functional level over time.

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