If you experience chest pain, shortness of breath or swollen feet and ankles following a bout of flu or viral infection, you should see a doctor to rule out a potentially fatal heart condition called viral myocarditis.

People with mild viral myocarditis may feel no symptoms at all or they may experience a heart attack or severe heart failure (dilated cardiomyopathy) as the condition worsens.

“Viral myocarditis may be the cause for a significant number of unexplained sudden deaths in seemingly healthy young people,” says Associate Professor Lim Chong Hee, Senior Consultant, Department of Cardiothoracic Surgery, National Heart Centre Singapore (NHCS), a member of the SingHealth group.

Patients with viral myocarditis may be mistaken as having the flu because of the initial flu-like symptoms such as fever, fatigue and heart palpitations, adds Assoc Prof Lim, who is also Director of the Heart and Lung Transplant Programme at NHCS.

Women who get viral myocarditis in their final month of pregnancy can develop a weakened heart condition called peripartum cardiomyopathy.

What is viral myocarditis?

Myocarditis is an inflammation of the heart muscle due to a viral infection. It weakens the heart’s ability to pump enough blood throughout the body and results in heartbeat irregularities (arrhythmias) and possible heart failure.

Common viruses affecting the heart include the adenovirus (common cold virus), the rubella virus (German measles) and coxsackievirus B (a virus that causes flu-like symptoms).

Myocarditis tends to affect more men than women, and the average patient age is 42 years.

What happens in severe myocarditis?

These heart conditions may develop:

  • Dilated cardiomyopathy
    A serious heart condition where the heart muscle becomes inflamed and enlarged, causing symptoms such as chest pain.
  • Arrhythmias
    The heart experiences abnormal or irregular heartbeats.
  • Heart attack or stroke
    When the heart’s pumping action fails, blood clots start forming in the heart. If the blood clot blocks a heart artery, this causes a heart attack. If the blocked artery is in the brain, it leads to stroke.
  • Sudden death
    When the heart stops beating due to worsening abnormal heart rhythms (arrhythmias), sudden cardiac death occurs.

Symptoms of viral myocarditis

It may begin with mild flu-like symptoms such as fever, but as the heart muscle gets weakened by the viral infection, you may experience:

  • Chest pain
  • Shortness of breath (at rest or during physical activity)
  • Abnormal heartbeat (arrhythmia)
  • Swollen legs, feet and ankles (edema)
  • Fatigue and weakness

How is viral myocarditis diagnosed?

Only a biopsy of the heart muscle – a high-risk test – can allow doctors to definitely diagnose viral myocarditis.

Myocarditis is usually diagnosed based on symptoms, after ruling out many other causes of heart failure.

The following tests may be ordered:

  • Electrocardiogram (ECG)
  • Echocardiography (ultrasound of the heart)
  • Blood tests

Treatment of viral myocarditis

There is no proven treatment for myocarditis.Treatment usually involves relieving the symptoms of heart failure, reducing inflammation of the heart muscle and treating the viral infection – with a regimen of antibiotics, anti-inflammatory medications, diuretics and bed rest.

In rare cases, patients can develop fulminant (sudden) heart failure. Their survival then depends on getting a heart transplant.

To “buy time” before the heart transplant and to prevent organ damage, the patient can be fitted with a temporary assist device such as ECMO (extracorporeal membrane oxygenation) or a ventricular assist device.

 

“Do not take flu symptoms lightly. Avoid strenuous exercise when having the flu. This reduces undue stress on the heart which might be inflamed from the viral infection. Seek emergency medical help if you feel unwell following a bout of flu,” advises Assoc Prof Lim.

Ref: S13