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It is unclear how many people around the world live with long COVID. However, one study that is yet to undergo peer review estimates that as of August 2021, about 43% of people who tested positive for COVID-19, and more than half of those who received hospitalized care for this disease, ended up developing long COVID.
The results of a survey published in eClinicalMedicineTrusted Source in July 2021 indicate that long COVID causes an array of diverse symptoms that “affect multiple organ systems, with impact on functioning and ability to work.”
The authors of this paper also point out that people with long COVID experience some unexpected conditions after their initial illness, including a hard-to-diagnose syndrome known as POTS.
POTS involves a complex mix of symptoms, including lightheadedness, brain fog, fatigue, headaches, blurry vision, heart palpitations, and nausea. These symptoms are linked to either low blood pressure or high blood pressure — hypotension or hypertension, respectively — although the precise cause behind these effects remains debatable.
Other dataTrusted Source indicate that acute COVID-19 can lead to various cardiovascular complications, including stroke, heart attack, arrhythmia, deep vein thrombosis, and pericarditis, which is inflammation of the heart membrane.
A study that appeared in Nature MedicineTrusted Source in February 2022 goes so far as to suggest that people who develop COVID-19 have an increased risk of experiencing cardiovascular problems a year after the initial disease.
According to the study authors, at 12 months post-COVID-19, people continue to have an increased risk of “cardiovascular disease spanning several categories, including cerebrovascular disorders, dysrhythmias, ischemic and non-ischemic heart disease, pericarditis, myocarditis, heart failure, and thromboembolic disease.”
What is more, they write, “The risks were evident regardless of age, race, sex, and other cardiovascular risk factors, including obesity, hypertension, diabetes, chronic kidney disease, and hyperlipidemia; they were also evident in people without any cardiovascular disease before exposure to COVID-19.”
To better understand how and why COVID-19 and long COVID have cardiovascular implications, in our latest In Conversation podcast, we have spoken with three experts and one person who continues to navigate the difficulties of living life with long COVID.
These individuals are:
- Angela Meriquez Vázquez, Body Politic president and long COVID patient
- Dr. Lesley Kavi, trustee and chair of PoTS UK and visiting professor at Birmingham City University, United Kingdom
- Dr. Artur Fedorowski, associate professor of cardiovascular medicine at the Karolinska Institute and Karolinska University Hospital in Stockholm, Sweden
- Dr. Tae Chung, assistant professor of physical medicine and rehabilitation at Johns Hopkins Medicine and director of the Johns Hopkins POTS Program
You can listen to our podcast below or use your preferred streaming service.
Cardiovascular complications of COVID-19
According to Dr. Fedorowski, “somewhere between 1% and 10% of individuals [who contracted SARS-CoV-2] will develop all these [cardiovascular] complications, [such as] myocarditis, pericarditis, and even blood clots building in [the] arteries.”
The difficulty in treating these cases, moreover, is [because] the cardiovascular impact can be difficult to pinpoint at first.
“We are talking about very small blood clots in very small arteries — they are not so easy to detect,” said Dr. Fedorowski. “But some patients may report having blue fingers out of nowhere, just being infected a few days before. And this might be a sign of a very small, tiny blood clot in [the] peripheral blood arteries.”
The Nature MedicineTrusted Source study that we referred to earlier in the article shows that there is an increased risk of a whole range of cardiovascular outcomes even in those not admitted to hospital with severe COVID-19 — that is, even in milder cases of the disease.
To reach this conclusion, the study authors analyzed data from a large cohort of “153,760 individuals with COVID-19, as well as two sets of control cohorts with 5,637,647 (contemporary controls) and 5,859,411 (historical controls) individuals.”
This ongoing risk of cardiovascular issues does not apply only to adults. According to a paper in CirculationTrusted Source in November 2020, children can also experience acute heart failure weeks after having had a SARS-CoV-2 infection. This is likely to be an effect of long COVID in children, which is also under investigation.
However, the syndrome that has most puzzled scientists regarding its association with long COVID is POTS.
What is POTS, really?
The medical community generally describes POTS, the syndrome that affects more and more people with long COVID, as a dysautonomic phenomenon — that is, something that affects the autonomic nervous system.
The autonomic nervous system is the body’s “autopilot mode,” which controls key bodily functions, such as heart rate, breathing, and digestion.
POTS is one of several forms of dysautonomia, alongside neurocardiogenic syncope, which involves frequent fainting spells and multiple system atrophy, a rare and fatal condition that leads to rapid systemic deterioration.
The symptoms of POTS are as numerous as they are varied, ranging from lightheadedness upon standing up from a seated position to tachycardia (an abnormally rapid heart rate), shortness of breath, and digestive symptoms.
This heterogeneity of symptoms can make POTS difficult to diagnose. Doctors often mistake it for an anxiety disorderTrusted Source, as symptoms such as a rapid heart rate and heart palpitations also occur in people who experience anxiety.
“The problem with POTS is that it seems to be not only a cardiovascular problem — [a] heart and vessel problem — [but also] a problem of your nervous system, sometimes on your gastrointestinal system,” Dr. Fedorowski explained.
“And in the end, we call it ‘dysautonomia,’ as it seems [to be] about your autonomic nervous system, which controls all your autonomic functions […]. And as the autonomic nervous system controls, first of all, your circulatory system, the main symptoms that you feel are from the circulatory or from your heart palpitations or blood pressure instability — you don’t feel good when you stand up, and so on. But the problems are a little bit diffused,” he noted, pointing out that even top specialists may find it hard to diagnose POTS correctly.
What causes POTS?
The mechanisms behind POTS remain unclear, but ongoing research is searching for the likeliest explanations.
A study published in February 2022 in Cells found that people with POTS have platelet storage pool deficiency, a phenomenon linked to symptoms such as frequent nosebleeds, dysmenorrhea, easy bruising, and anemia.
It also showed that people with POTS have elevated inflammatory biomarkers, all of which may suggest a state of chronic inflammation.
“[T]he data provided [in this study] suggest that POTS is a mixed inflammatory pattern disease,” the authors conclude.
POTS before and after COVID-19
Although more and more media content has started looking at POTS as a long-term effect of SARS-CoV-2 infections, POTS itself is not a newly emerged syndrome.
According to data that the nonprofit organization Dysautonomia International cited well before the pandemic, an estimated 1–3 million people in the U.S. had POTS.
Although it is unclear how many more people are seeking care in the aftermath of COVID-19 than they were pre-pandemic, anecdotal reportsTrusted Source seem to indicate a steep increase in cases, most of them associated with long COVID.
Dr. Fedorowski also told us that he and his colleagues at the Karolinska University Hospital in Sweden have been seeing an influx of people with long COVID whom doctors have referred for POTS treatment:
“We experience a huge inflow of new referrals from different parts of the region of Stockholm, meaning that in the Stockholm area, [where] we have around 2.5 million citizens, […] from [that] whole area, we are getting referrals from primary care doctors [and] from other specialists from other hospitals regarding people who developed what we call ‘long COVID’ or ‘post-COVID syndrome.’ The main reason they are sent to us is that [here] is quite [a] high clinical suspicion of POTS — postural orthostatic tachycardia syndrome.”
According to Dr. Fedorowski, at almost 2 years into the COVID-19 pandemic, the number of referrals for POTS rehabilitation “has doubled or tripled.”
Dr. Chung made a similar observation about the Johns Hopkins POTS Program, saying that he and his colleagues “have [had] at least twice or three times more referrals” at their clinic since the start of the pandemic, compared with pre-pandemic numbers.
And Dr. Kavi told us that the situation is the same in the U.K.: “Here, the feedback that I’m getting from the clinicians that we work with — who run POTS services and secondary care […] — [is] that they’re noticing a significant increase in their referrals. And, of course, that means that their waiting lists are getting longer as well.”