QUEBEC CITY — The cardiovascular sequelae of COVID and its vaccinations are an ongoing clinical challenge in Canada, such that the Canadian Cardiovascular Society dedicated an educational session at the Canadian Cardiovascular Congress (CCC) 2025 to the scope of the problem and how to address it.

“A lot of people still do not believe that [long COVID] exists until they see a few patients of their own,” Thao Huynh, MD, cardiologist at the McGill University Health Centre in Montreal, told Medscape News Canada.

“Everybody should be able to treat long COVID patients,” said Huynh, who offers peer-to-peer education on the topic. But to do so requires “patience and empathy” and a willingness to work through the symptoms with the patient. A goal of the educational session was to help clinicians do just that.

Cardiovascular Impact

Naveed Janjua, MBBS, DrPH, executive director of epidemiology and intelligence services at the British Columbia Centre for Disease Control, Vancouver, shared epidemiologic data on the cardiovascular impact of COVID. A population-based study conducted in British Columbia revealed an increased risk for major cardiovascular adverse events (adjusted hazard ratio [HR], 1.34) and acute myocardial infarction (adjusted HR, 1.65) following SARS-CoV-2 infection, with a median follow-up period of 260 days. In addition, a meta-analysis of post-acute cardiovascular effects of COVID revealed a greater than fivefold increased risk for myocarditis in the year following the index infection (HR, 5.16).

Huynh followed with a report on her experience treating patients with long COVID-related myopericarditis. She and her team showed in the IMPACT QUEBEC COVID-19 Long Haul Study that, among a sample of 276 patients with a post-COVID condition, 38% had cardiac involvement confirmed via MRI. Symptoms were debilitating and most often included dyspnea (95%), pleuritic chest pain (86%), and palpitations (84%).

A major challenge to diagnosing long COVID-related myopericarditis is that preliminary testing (including C-reactive protein and troponin levels, as well as echocardiography) typically yields normal results. More useful diagnostic tests include sedimentation rate and N-terminal pro-brain-type natriuretic peptide, but these tests can also be normal in the context of severe myopericarditis, which is usually identifiable via cardiac MRI (CMR).

Barriers to Care

Wait times for CMR can be months or even years in Canada, so Huynh recommended starting treatment in the context of high clinical suspicion, even before receiving a confirmatory CMR. To make the diagnosis, she said, physicians must “listen to the patient,” which can be difficult for cardiologists who see a high volume of patients each day.

Bias can also be a barrier. “The majority of cardiologists are men. The majority of patients with long COVID are female, and there’s a myth that the females [with long COVID] have a psychiatric disease,” she said.

Huynh’s first-line approach to treatment is colchicine, with anakinra as a second-line option, if accessible. She emphasized that patients absolutely require treatment because they are highly debilitated and do not recover spontaneously, even after several years.

One should not take a wait-and-see approach to this condition, Huynh said. She would like to try other anti-inflammatory biologic therapies, but insurance will not cover off-label use, and Huynh has been unable to secure support from industry.

Vaccine-Associated Myocarditis

In rare cases, myocarditis can occur following vaccination for COVID, Michael Khoury, MD, assistant professor of pediatrics at the University of Alberta in Edmonton, said during the presentation that followed. The incidence of vaccine-related myocarditis overall is approximately 1.2 per 100,000 doses, but this estimate increases to as high as 39 per 100,000 doses among adolescent and young adult males, who represent the group at highest risk.

The pathway to diagnosis for vaccine-induced myocarditis is more straightforward than that for long COVID-related myopericarditis, said Huynh. Young men typically arrive at the emergency department with chest pain and receive a CMR, which often shows fibrosis and may also reveal reduced ejection fraction. Nevertheless, CMR can be delayed in these patients as well.

Vaccine-induced myocarditis is also much more likely to resolve on its own after 3-6 months, although patients must be closely monitored during this period and limit physical activity. Many patients continue to have evidence of fibrosis on CMR, and the long-term implications of this finding are unknown.

The MYCOVACC study is monitoring myocarditis following messenger RNA (mRNA) COVID vaccination across Canada, and an update of this effort was presented by Nathaniel Hawkins, MD, MPH, assistant professor of cardiology at the University of British Columbia, Vancouver. So far, the team has identified 359 cases, of which 51% are probably, 41% are definitely, and 8% are likely related to the mRNA vaccine. The most common manifestation is myocarditis (55.7%), but 13.5% of patients have pericarditis, and 30.8% have both. As expected, most cases are in young males.

Most cases occurred after receiving the original Pfizer (52%) or Moderna (44%) vaccine, usually when it was delivered as a first (24%) or second (64%) dose. The risk with the newer vaccines and with additional boosters is much lower, Hawkins said.

Symptoms (most commonly, chest pain and dyspnea) usually present within a week of receiving the vaccine. Patients are usually treated with nonsteroidal anti-inflammatory drugs, with or without colchicine, or cardiac medications (most often beta-blockers or renin-angiotensin system inhibitors). Patients often spend 1-4 nights in the hospital.

Janjua, Khoury, and Hawkins reported having no relevant financial relationships. Hyunh reported having received support from Moderna. The IMPACT-QUEBEC COVID-19 Long Haul Study received support from Pfizer. MYCOVACC was funded by the Public Health Agency of Canada.