Tachycardia Syndrome May Be a Distinct Marker for Long COVID

Marcia Frellick

August 13, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Tachycardia is commonly reported in patients with post-acute COVID-19 syndrome (PACS), also known as long COVID, authors report in a new article. The researchers say tachycardia syndrome should be considered a distinct phenotype.

Dr Marcus Ståhlberg

The study by Marcus Ståhlberg, MD, PhD, of Karolinska University Hospital, Stockholm, Sweden, and colleagues was published online August 11 in The American Journal of Medicine.

Ståhlberg told Medscape Medical News that although much attention has been paid to cases of clotting and perimyocarditis in patients after COVID, relatively little attention has been paid to tachycardia, despite case reports that show that palpitations are a common complaint.

"We have diagnosed a large number of patients with postural orthostatic tachycardia syndrome [POTS] and other forms of COVID-related tachycardia at our post-COVID outpatient clinic at Karolinska University Hospital and wanted to highlight this phenomenon," he said.

Between 25% and 50% of patients at the clinic report tachycardia and/or palpitations that last 12 weeks or longer, the authors report.

"Systematic investigations suggest that 9% of Post-acute Covid-19 syndrome patients report palpitations at six months," the authors write.

The findings also shed light on potential tests and treatments, he said.

"Physicians should be liberal in performing a basic cardiological workup, including an ECG [electrocardiogram], echocardiography, and Holter ECG monitoring in patients complaining of palpitations and/or chest pain," Ståhlberg said.

"If orthostatic intolerance is also reported ― such as vertigo, nausea, dyspnea ― suspicion of POTS should be raised and a head-up tilt test or at least an active standing test should be performed," he said.

If POTS is confirmed, he said, patients should be offered a heart rate–lowering drug, such as low-dose propranolol or ivabradine. Compression garments, increased fluid intake, and a structured rehabilitation program also help.

"According to our clinical experience, ivabradine can also reduce symptoms in patients with inappropriate sinus tachycardia and post-COVID," Ståhlberg said. "Another finding on Holter-ECG to look out for is frequent premature extrasystoles, which could indicate myocarditis and should warrant a cardiac MRI."

Ståhlberg said the researchers think the mechanism underlying the tachycardia is autoimmune and that primary SARS-CoV-2 infections trigger an autoimmune response with formation of autoantibodies that can activate receptors regulating blood pressure and heart rate.

Long-lasting symptoms from COVID are prevalent, the authors note, especially in patients who experienced severe forms of the disease.

In the longest follow-up study to date of patients hospitalized with COVID, more than 60% experienced fatigue or muscle weakness 6 months after hospitalization.

PACS should not be considered a single syndrome; the term denotes an array of subsyndromes and phenotypes, the authors write. Typical symptoms include headache, fatigue, dyspnea, and mental fog but can involve multiple organs and systems.

Tachycardia can also be used as a marker to help gauge the severity of long COVID, the authors write.

"[T]achycardia can be considered a universal and easily obtainable quantitative marker of Post-acute Covid-19 syndrome and its severity rather than patient-reported symptoms, blood testing and thoracic CT-scans," they write.

An Underrecognized Complication

Erin D. Michos, MD, MHS, director of women's cardiovascular health and associate director of preventive cardiology at Johns Hopkins University School of Medicine, Baltimore, Maryland, told Medscape Medical News that she has seen many similar symptoms in the long-COVID patients referred to her practice.

Dr Erin Michos

Michos, who is also an associate professor of medicine and epidemiology, said she's been receiving a "huge number" of referrals of long-COVID patients with postural tachycardia, inappropriate sinus tachycardia, and POTS.

"I think this is all in the spectrum of autonomic dysfunction that has been recognized a lot since COVID. POTS has been thought to have potentially a viral cause that triggers an autoimmune response. Even before COVID, many patients had POTS triggered by a viral infection. The question is whether COVID-related POTS for long COVID is different from other kinds of POTS."

She says she treats long-COVID patients who complain of elevated heart rates with many of the cardiac workup procedures the authors list and that she treats them in a way similar to the way she treats patients with POTS.

She recommends checking resting oxygen levels and having patients walk the halls and measure their oxygen levels after walking, because their elevated heart rate may be related to ongoing lung injury from COVID.

Dr Eric Adler

Eric Adler, MD, a cardiologist with University of San Diego Health, San Diego, California, told Medscape Medical News that the findings by Ståhlberg and colleagues are consistent with what he's seeing in his clinical practice.

Adler agrees with the authors that tachycardia is an underrecognized complication of long COVID.

He said the article represents further proof that though people may survive COVID, the threat of long-term symptoms, such as heart palpitations, is real and supports the case for vaccinations.

The authors, Michos, and Adler have disclosed no relevant financial relationships.

Am J Med. Published online August 11, 2021. Full text

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune and Nurse.com and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick.

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