Coronavirus: Medical studies

S'pore team studying why some hit by Covid-19 suffer heart damage

Mounting evidence overseas suggests some patients continue to suffer long-term complications even after recovery. PHOTO: ST FILE

A team of doctors and researchers in Singapore has started a cardiac research programme to better understand why some patients who are hit hard by Covid-19 also suffer heart damage, and how to prevent this from happening.

The National University Heart Centre, Singapore (NUHCS) team aims to recruit 100 Covid-19 patients as mounting evidence overseas suggests that some patients continue to suffer long-term complications even after recovery.

Though serious complications related to the heart after recovery here are not common, doctors say they are monitoring the situation closely.

Professor Tan Huay Cheem, director and senior consultant at NUHCS, said Covid-19 should be viewed as impacting the entire vascular system, including the heart, lungs, kidneys, liver and brain, and not just a specific organ system.

"Sorting out the long-lasting symptom of lethargy or breathlessness will entail assessment of lung, heart and other organ functions at the same time," said Prof Tan.

The programme by the Cardiovascular Research Institute within NUHCS includes a clinical study using known protein biomarkers to identify patients at risk of developing serious cardiovascular complications after they recover from the virus.

There is evidence globally to show that some patients continue to suffer long-term complications.

For instance, a recent Jama Cardiology study of 100 recently recovered Covid-19 patients in Germany found that three quarters of them suffered from heart inflammation.

The characteristics are impaired ability of the heart to contract, scar formation and enlargement of the heart.

The study, published late last month, noted the possibility of future heart failure as a result of the patients' condition. Calling the German study significant and alarming, Prof Tan said cardiovascular magnetic resonance imaging - which was used in the German study - is the most accurate tool in evaluating heart function and health.

  • Findings from overseas studies

  • Evidence that Covid-19, initially thought to be a respiratory disease, can also do serious heart damage has surfaced recently. Two studies overseas throw up such findings:


    This study showed the presence of cardiovascular magnetic resonance (CMR) abnormalities in 78 patients, two to three months after testing positive for the virus, though the majority, or 67 of them, had only mild symptoms and did not require hospitalisation.

    CMR imaging is the most accurate way of evaluating heart function, volume, heart mass and the presence of scarring.

    Of the 100 patients, who have a median age of 49, 53 of them are male.

    CMR imaging was done irrespective of pre-existing conditions, the severity and overall course of Covid-19 infection, the time from the original diagnosis or the presence of cardiac symptoms.

    The most prevalent abnormality was myocardial inflammation, which is the inflammation of the heart muscle resulting in degeneration or death of heart muscle cells.


    The survey looked at 1,216 patients from 69 countries across six continents, and showed that 55 per cent of Covid-19 patients had abnormal heart findings.

    These abnormalities were unnoticed or severe, and imaging changed the way the condition was being managed in one-third of the patients.

    Clara Chong

Dr Shawn Vasoo, clinical director of the National Centre for Infectious Diseases (NCID), said the impact on organs outside the lungs can be detected only through further diagnostic testing such as cardiac imaging and laboratory testing.

He stressed the importance of developing ways to determine which patient would require these further tests. "This will then help us to develop directed treatment and prevention strategies for such complications," he added.

At NCID, follow-up procedures with patients take place on three fronts. First, patients who had a more serious course of Covid-19 - such as severe pneumonia with residual respiratory problems, cardiac inflammation or injury, or a clotting disorder - are seen by the corresponding medical specialists.

For patients who suffered only a mild course of Covid-19 and have no apparent complications, they are reminded to seek medical attention should any new and persistent symptoms develop, such as shortness of breath and chest pain.

Finally, patients who are eligible and willing are also given the opportunity to enrol in a research study which aims to track patients for up to two years.

The German study is not the only one throwing up such findings.

A global study of 1,216 patients from 69 countries across six continents, which used traditional ultrasound imaging to study the heart, showed that 55 per cent of Covid-19 patients had abnormal heart findings, Prof Tan said. It was published in the European Heart Journal - Cardiovascular Imaging in June.

The association between Covid-19 and heart inflammation is unclear, Prof Tan said.

Heart inflammation may not be directly due to viral invasion but caused instead by an impaired and overactive immune response from the body, he added.

The effects on other vital organs, like the brain, or clotting abnormalities may be equally life-threatening.

While most patients have recovered uneventfully, there are some who have clinically apparent complications, and others in which such complications are not obvious, Dr Vasoo said.

He added: "Work is ongoing to understand better who is at risk, and to detect these earlier - and this will pave the way for pre-emptive monitoring and our therapeutic approaches."

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A version of this article appeared in the print edition of The Straits Times on August 31, 2020, with the headline S'pore team studying why some hit by Covid-19 suffer heart damage. Subscribe