Many who are on the mend from COVID-19 may have noticed a confusing symptom plaguing them for weeks: a sudden, unexplained spiking of their heart rate.

For some people, it鈥檚 a brief, uncomfortable reminder of the acute phase of illness while they work back towards their usual level of fitness.

But heart palpitations and confusing spikes in heart rate are also one of the most common symptoms plaguing those with long COVID, a little-understood condition that can linger for months or even years after a person first contracted the virus.

While this cardiac symptom doesn鈥檛 appear to stem from long-term damage to the heart, experts say, spiking heart rates can provide anxiety and discomfort for thousands of Canadians, disrupting their lives and activities.

鈥淭hink of your body as an automatic car,鈥 Dr. Angela Cheung told CTVNews.ca. 鈥淎nd there's disturbance there, meaning it's not responding appropriately or it's taking longer to respond appropriately. So that's really what's happening."

So how do you tell the difference between a temporary issue and a larger problem that needs medical advice?

HIGH HEART RATE AFTER COVID-19

Patients dealing with cardiac symptoms of long COVID is something that Dr. Ian Paterson sees a lot.

Paterson, a cardiologist and professor at the University of Alberta, works at the Mazankowski Alberta Heart Institute, where he has had many patients referred to him because of their cardiac issues following COVID-19 infections.

鈥淧alpitations or erratic heart beat, yeah, that would rank up there as one of the more common symptoms that I get asked to provide advice about,鈥 he told CTVNews.ca in a phone interview, adding that chest pain is another common symptom he is asked about.

鈥淪ome patients have these spikes in their heart rate, often the spikes happen with minimal activity.鈥

Last summer, Paterson helped the Canadian Cardiovascular Society to help in treating long COVID patients with cardiac symptoms.

For some patients who experience spiking heart rates in the first few weeks after illness, this may not be a precursor of long COVID, but a part of the healing process.

鈥淚f a patient was quite ill and was on bedrest for several weeks, then the body rapidly loses muscle mass and you lose a good amount of your fitness,鈥 Paterson said. 鈥淎nd so when you exert yourself, you will have higher heart rates with exertion and even at rest, because you're just not at the same level of fitness that you were before your illness.鈥

Vancouver resident Angela Inglis believes this is what happened to her.

The 41-year-old fell ill with COVID-19 around Jan. 21. Her entire family caught the virus through her son鈥檚 daycare, and battled the illness for around two weeks at home.

But after the intense stage of sickness passed, another issue arose: an uneasily high heart rate.

鈥淲hen I started to try to work out again, which was probably too soon, I noticed that I felt like my heart was beating faster than the energy I was exerting,鈥 she told CTVNews.ca. 鈥淪o I felt like I was getting heart palpitations.鈥

She even felt like her heart was racing when she tried to fall asleep.

鈥淚 wasn't sure if it was anxiety or if it was something to be more concerned about.鈥

She was able to get in touch with Paterson to explain her symptoms in mid-February. He reassured her that she was missing some of the accompanying symptoms that might indicate a larger problem, and that her symptoms were common.

鈥淚t's helpful to know that what I had experienced is not necessarily outside of the ordinary for COVID and that, it doesn't mean there's something wrong with my heart,鈥 she said.

Now, around a month since she first caught COVID-19, she says her heart rate feels like it is returning to normal.

But for many people, their cardiac symptoms don鈥檛 go away in a month.

Instead it becomes part of long COVID, a condition which can impact multiple organ systems and includes a wide range of symptoms.

鈥淚n terms of the frequency in long COVID, my understanding of the literature is about 25 to, let's say, 30 per cent of patients with long COVID syndrome will have chest pain and/or palpitation type symptoms,鈥 Paterson said.

鈥淸And] long COVID appears to happen just as common in people that had mild initial cases of COVID compared to hospitalized patients. So it's not more common in the people who are hospitalized.鈥

HIGH HEART RATE AND LONG COVID

Long COVID is considered by some physicians and guidelines to be any symptoms that extend beyond four weeks after a person has caught COVID-19.

But in October, WHO came out with a clinical case definition, stating that symptoms were part of long COVID only if they extended past three months since the first onset of COVID-19.

鈥淭he most common [symptoms of long COVID] are fatigue, brain fog, tachycardia or fast heart rate, shortness of breath and sleep disturbances. Those are the top five,鈥 Cheung told CTVNews.ca in a phone interview.

Cheung, a professor at the University for Toronto and senior scientist at the University Health Network, is co-lead on (CANCOV), a Canadian project looking to research outcomes up to two years after contracting COVID-19.

鈥淭here are many cardiac things that can happen post COVID,鈥 she said. 鈥淲hat I would call inappropriate sinus tachycardia is something that we do see.鈥

Inappropriate sinus tachycardia (IST) is when the heart beats very quickly without a clear reason.

She said that most heart rate issues seen in long COVID patients are probably IST, but some appear to be more similar to another condition.

鈥淲e don't understand fully why, but some patients with post COVID syndrome are at risk for developing cardiac dysautonomia, and another condition called POTS, which stands for postal orthostatic tachycardia syndrome,鈥 Paterson said.

鈥淎nd that鈥檚 fancy words for meaning your heart rate shoots up when you stand, when you get up to a standing position or when you exert yourself, you have inappropriate increases in heart rate.鈥

POTS isn鈥檛 just an elevated heart rate 鈥 it also involves abnormal blood flow throughout the body. Patients experiencing symptoms of POTS are often diagnosed with IST if they don鈥檛 fulfill all the criteria of POTS, Cheung said.

It鈥檚 known that COVID-19 affects the cardiovascular system. The virus increases the risk of developing myocarditis, an inflammation of the heart, and studies have suggested that those who have recovered from COVID-19 are at a higher risk for heart attack and stroke.

But scientists aren鈥檛 100 per cent sure yet why these cardiac symptoms arise and persist in long COVID patients.

鈥淐OVID affects our autonomic nervous system,鈥 Cheung said. 鈥淎nd so there's a bit of an imbalance in the autonomic nervous system and there鈥檚 decreased parasympathetic activity which may explain this phenomenon.鈥

A on long COVID and the cardiovascular system which was published this month in the European Heart Journal listed a number of factors that may play into ongoing cardiac issues, including that there could be injury to tiny blood vessels in the heart causing stress, or that there could be a chronic inflammatory response.

鈥淭he most prevailing theory is it's somehow caused by a low level of ongoing inflammation that people have following their illness, that the body, for some reason, in, in these patients, [鈥 the inflammation was activated after their illness,鈥 Paterson explained.

鈥淎nd it just is persisting much, much longer than it should.鈥

He said that some blood tests can show evidence that the immune system is still active at a level it shouldn鈥檛 be.

鈥淲e measure something called CRP or D-dimers,鈥 Paterson said, explaining that high levels of these in the body can be markers for long COVID.

Not every long COVID case has these markers, he cautioned, but 鈥渋n some cases we do see these markers in terms of the specific cardiac issues.鈥

THE ROAD TO RECOVERY

The good news for those who might be experiencing jumps in their heart rate after COVID-19 is that it鈥檚 not a life-threatening issue or necessarily indicative of underlying heart damage.

鈥淭hat's the first thing I tell the patient. I鈥檇 say, 鈥榊es, what you're having is uncomfortable. Yes, you鈥檙e getting tired more easily, but this is something which should improve over time and is not life threatening,鈥欌 Paterson said.

鈥淲e'll often also send these patients for a heart ultrasound and in all the cases that I've been involved with, their heart function has been normal.鈥

Paterson said that with his patients who have POTS, hydration is important, and sometimes they are told to wear compression garments such as stockings in order to help their blood circulation and return blood to their heart.

While treating long COVID is still a field with a lot of 鈥渢rial and error,鈥 physical therapy is involved in many treatment plans for these cardiac symptoms, he said.

鈥淚n many centers in Canada and really throughout the world, there have become specialized exercise programs for patients with long COVID that really have become personalized for these patients, depending on the symptoms that they're having,鈥 he said.

鈥淲hat I've been doing is I've been referring patients to these more specialized physiotherapy groups.鈥

One type of physical therapy that people with cardiac dysautonomia might do is to slowly move from exercise lying in a recumbent position to a standing position over a period of time to help the body adjust, he said.

鈥淚 have had some patients that I follow up with and for the most part, the symptoms seems to improve,鈥 Paterson said. 鈥淚t can take a while and that's what I usually warn them is depending on their level of disability, it can take [months].鈥

He said in a handful of cases the patient said they only started feeling close to normal after six months of dealing with these symptoms.

Both Cheung and Paterson said that when we talk about these cardiac symptoms with long COVID, it鈥檚 important not to spread alarm.

鈥淲hat I would say about cardiac issues in long COVID is these are real issues that these patients have and at the same time, I think these are treatable issues and I wouldn't view them as life threatening,鈥 Paterson said, reiterating that there hasn鈥檛 been a connection found between spiking heart rates in long COVID and underlying heart damage.

鈥淚 think with the right help, people can improve from these issues.鈥

But at the same time, it鈥檚 important to educate people and provide support to those who may be struggling with these symptoms and feeling unsure if they鈥檙e overreacting or not.

鈥淚f your heart was going very quickly, yes, you would feel lightheaded and in a severe case, you could pass out,鈥 Paterson said. 鈥淒oes it affect people's day to day living and what they're able to do? Absolutely.鈥

Cheung said if a person is experiencing persistent chest pain after COVID-19, they shouldn鈥檛 wait until three months have passed to reach out to a medical professional about long COVID.

With milder symptoms such as a high heart rate, a person could try to rest, go slowly when returning to physical activity, and see if the issue is continuing beyond the few weeks it might take to regain physical fitness.

Inglis said it was helpful to her to reach out for advice even though only a few weeks had passed since she contracted COVID-19.

鈥淚t was certainly feeding into anxiety,鈥 she said of her heart palpitations, adding that she recommended people ask their doctor about their concerns.

Most people with long COVID will have more than one symptom, Cheung said.

鈥淎 lot of people not only have cardiac symptoms, they also have brain fog and they also have fatigue,鈥 she said.

鈥淪ome of these things that we're talking about [with long COVID], we're not talking about weeks, we're talking about months to years. So some people have had it for two years and really don't want that, right. It's very debilitating. It affects quality of life.鈥