​[Photo courtesy of Lee Pei Hsia] Ms Lee Pei Hsia in hospital receiving treatment to drain excess fluid from her lungs due to myocarditis.

  • Viral infections such as Covid-19, influenza, dengue, and hepatitis B and C can lead to myocarditis
  • The National Heart Centre Singapore has seen slightly more cases of this condition of heart inflammation during the Covid-19 pandemic
  • A doctor said the increase could be due to more people getting Covid-19 that then led to myocarditis
  • Young healthy individuals can develop myocarditis due to an over-activation of immune responses triggered by an acute infection
  • A 30-year-old talked about her “scary” experience with heart inflammation that was not Covid-19-related
SINGAPORE — In May, Ms Lee Pei Hsia came down with a fever. What had initially looked like a viral infection led to a serious case of acute myocarditis, which is an inflammatory condition of the heart muscle.

The 30-year-old financial adviser said: “I thought it was just a common infection. I didn’t expect that it would be so serious and affect my heart.”

Being young and healthy, Ms Lee did not see the heart inflammation coming.

After developing a fever, she recalled feeling weak and had trouble falling asleep at night due to chest pain and breathlessness. She also vomited. 

“I couldn’t move my body. I knew something was wrong when I could not walk and had to be supported,” she said.

At the emergency department of a public hospital, she was suspected to have had a heart attack at first, but scans later showed that it was myocarditis.


Viral infections are one of the common causes of myocarditis.

This heart condition came to be in the news more frequently during the Covid-19 pandemic when infected patients or those who took the vaccine developed the condition.

Assistant Professor Louis Teo, senior consultant at the department of cardiology at National Heart Centre Singapore (NHCS), explained that the Sars-Cov-2 coronavirus, which causes Covid-19, can directly infect the heart cells and damage them.

Or the virus can trigger excessive inflammatory and immune responses in the body, leading to white blood cells attacking the heart.

However, it is not just the Sars-CoV-2 coronavirus that can cause myocarditis.

Clinical and interventional cardiologist Derek Yong, one of the doctors who treated Ms Lee earlier this year, said that common viruses can do that, too.

They include the adenovirus (which causes cold-like symptoms), influenza virus, and the dengue, hepatitis B and C, varicella and rubella viruses.

Dr Yong is the medical director for Restore Heart Centre and co-medical director for Prime Heart Centre.


Asst Prof Teo said that younger adults are at a higher risk of developing myocarditis due to their robust immune system.

At NHCS, doctors typically see the condition affecting “young healthy adults in their 30s to 40s”.

“They were previously healthy individuals without past medical problems and developed sudden myocarditis,” Asst Prof Teo said.

“Young adults with robust immune system have an over-activation of the immune responses triggered by (acute viral or bacterial infections). This leads to the immune system self-attacking the heart muscle, causing myocarditis.”

Worldwide, myocarditis is estimated to affect 10 to 20 people for every 100,000 people, Asst Prof Teo said.

NHCS, which sees around 20 to 30 myocarditis cases each year, has seen a slight increase in cases since the start of the Covid-19 pandemic in 2020.

Asst Prof Teo said that NHCS saw around five to 10 more myocarditis cases a year during the pandemic, but added that the actual increase in the number of cases in Singapore is unknown.

The increase could be due to people getting myocarditis after being infected with Covid-19, he added.

In another group of patients, myocarditis can occur due to underlying autoimmune disorders such as hyperthyroidism, rheumatoid arthritis and lupus erythematosus, Asst Prof Teo said.

Ms Lee said that her doctors believed her myocarditis episode was likely related to a viral infection since she had a fever before she took a turn for the worse.

However, they were not able to pinpoint the type of virus. She tested negative for Covid-19.

Ms Lee said that myocarditis linked to Covid-19 vaccination was also ruled out. She received her first booster shot about three months before she fell ill. 


Myocarditis is one of the reported "adverse events" or undesirable medical conditions that can occur from Covid-19 vaccination.

Such cases usually happen within a week of vaccination, an advisory by the United States Centers for Disease Control and Prevention stated.

However, Asst Prof Teo from NHCS pointed out that the risk of developing myocarditis due to Covid-19 is “much higher” than the risk of getting myocarditis from a Covid-19 vaccine.

Dr Yong said that the majority of vaccination-linked myocarditis cases occurred after the second dose in younger adults, with 82 per cent occurring in males and at a median age of 21 years old.

The risk is about 50 to 100 cases for every million doses of a messenger ribonucleic acid (mRNA) vaccines in males and six to 11 cases for every million doses in females in the same age group, he added.

The study, led by researchers in Singapore, concluded that 18 people out of every million vaccine doses administered developed heart inflammation. It was published in The Lancet Respiratory Medicine medical journal in April.

In comparison, Asst Prof Teo said studies showed that the incidence of myocarditis is estimated to be 100 to 200 for every 100,000 people infected with Covid-19, although the reported incidence varies in different epidemiological studies in different countries.

“Therefore, we strongly suggest that people get vaccinated against Covid-19 because the benefits of preventing serious illness from Covid-19 outweigh the potential small risks,” he added. 

Dr Yong said that vaccinations for viral infections such as measles, rubella and mumps have also been effective in preventing some forms of viral myocarditis.

“As a result of widespread use of vaccination in developed countries, myocarditis that occurs as a result of infections — such as measles, rubella, mumps, poliomyelitis and influenza — is now rare.”


Asst Prof Teo from NHCS said that symptoms suggesting myocarditis include chest pain or discomfort, shortness of breath and palpitations (such as fast heartbeats or skipped heartbeats). There may also be non-specific symptoms such as fatigue.

However, many cases of myocarditis likely go undetected because they are asymptomatic or sub-clinical, meaning there are no symptoms, Dr Yong said.

For Ms Lee, she wanted a second medical opinion after she was diagnosed at the public hospital and warded. She was transferred to a private hospital when a bed was available after about a week.

At one point, her heart function dropped drastically. Doctors prepared her for the possibility of requiring a heart transplant if medications did not work.

She also had excessive fluid in her lungs, and around 1 litre of fluid was drained from them — a procedure she described as “scary” and “painful”.

Excess fluid can build up in the body when the heart is not functioning well and does not pump blood as well as it should.

Lee Pei Hsia and daughter
[Photo courtesy of Lee Pei Hsia] Ms Lee Pei Hsia with her daughter.

Recounting her painful and frightening experience, the young mother said that her immediate thoughts were of her family. This was when her doctors prepared her for the possible scenarios of requiring a heart device or heart transplant.

“I wondered if I would survive it. The first thought that came to my mind was my two-year-old daughter,” she said.

She was worried about her daughter’s physical and financial needs, that if anything were to happen to her, it would be tough for her husband to care for their daughter as a single parent and being self-employed.

“I felt that I’d not done enough. My time was not up yet. I told Dr Derek (Yong) that I would stick to the option (of medication). I prayed and held on to the belief that my heart would recover.”

For some, myocarditis can be fatal. A small group of patients may develop a sudden but uncommon form of myocarditis known as fulminant myocarditis, Asst Prof Teo said.

“Fulminant myocarditis is characterised by sudden and severe heart inflammation, leading to death from cardiogenic shock (severe heart failure), to ventricular arrhythmias (severe abnormal heartbeats) to multi-organ failure.”

At NHCS, the death rate for this severe form of myocarditis is one to two patients a year.


Treatment and recovery depend on the severity of the disease. 

Dr Yong said: “Most patients with acute myocarditis have partial or full clinical recovery with no lasting effects.

“In some cases, the process may continue and eventually become severe enough to produce long-term symptoms, often with enlarged hearts and heart failure, which may require (heart) transplantation.”

Asst Prof Teo said that mild cases may not require drug therapy, but the more severe cases will need antivirals or antibiotics, immunosuppressive therapy to suppress the immune system, and heart failure drugs. 

“(The mild cases) would just require observation in the hospital with blood tests and heart scan monitoring,” he added.

“Those severely or critically ill patients with myocarditis may need mechanical circulatory support such as extracorporeal membrane oxygenation (Ecmo) in the intensive care unit.”

Ecmo is a treatment that uses an artificial heart and lung to take over cardiac and respiratory function temporarily, giving the patient’s heart or lung, or both, time to recover.

If heart function is permanently damaged, patients will need long-term mechanical heart support in the form of a left-ventricular assist device (LVAD) or a heart transplantation, Asst Prof Teo said.

Ms Lee believes that swift action from her doctors have helped her recover, and she is grateful to them.

She received intravenous immunoglobulin therapy as part of her treatment, and was warded for about two weeks. She also received medications for heart failure.

In the case of acute myocarditis, the immunoglobulin therapy helps to suppress the autoimmune and inflammatory process, Dr Yong said.

Scans later showed that her heart function had gone back to normal.

“I’m relieved. Although I’m slowing down my pace of work, I’m grateful to be alive,” the self-confessed workaholic said. This health scare has made her rethink her fast-paced lifestyle that was packed with back-to-back appointments daily.

“My doctor said I’m one of the luckier cases who recovered fast. He mentioned seeing a teenage patient who required a heart transplantation.”

Despite her recovery, Ms Lee feels that her stamina is no longer the same. She cannot lift and carry heavy items, including her 12kg toddler.

“Sometimes when I work or walk too much, my heart feels a bit achy. I don’t think I can rush around for work anymore,” she added.

“Thankfully, my two-year-old is able to understand why I can’t carry her. I told her ‘my heart pain’.”

Ms Lee said that her myocarditis experience showed how unpredictable life can be and people should not take their health for granted.

She also wanted to highlight the importance of having adequate insurance coverage and savings in case of rainy days — something that she learnt from her own childhood experience.

Her mother had struggled to make ends meet as a cleaner after her father died early due to brain cancer when she was 14.

“Without my hospitalisation plan, I think my (out-of-pocket expenses) would add up to about S$40,000 to S$50,000 for my (myocarditis) treatment,” she said.

The bill included treatments at a public hospital and private hospital.

“Many young people think nothing will happen to them… but life is unpredictable,” Ms Lee said. 

Original article link from TODAY: