Coming down with serious respiratory illnesses like influenza (commonly called as flu) can have detrimental effects on the heart. In severe cases, viral infection can lead to arrhythmia (irregular heartbeats) and other heart disease.
Influenza is a respiratory illness that affects either the upper or lower respiratory tract. It is a viral infection. Dr Sivaresmi Unnithan, consultant pulmonology, Fortis Anandapur, Kolkata, says it causes fever, runny nose and sore throat, depending on the type of virus that has caused the infection. If it affects the immunocompromised like young children and the elderly, they can develop pneumonia.
Effects of flu
Dr G R Kane, Director, Cardiology, Kokilaben Dhirubhai Ambani Hospital, Navi Mumbai, adds that flu is a common term used for almost all viral infections. “Generally, it causes infection in the nose, throat, inflammation in the muscles and pain. But only in about 10% of the cases, the virus can spread and affect the heart,” he says.
Dr Unnithan says, “Most viruses that cause common cold or flu, do not really affect the heart like rhinovirus, adenovirus and respiratory syncytial virus. There are some influenza viruses which can affect the heart and cause inflammation of the heart muscles, leading to the condition called myocarditis.”
Is there a link between flu and heart disease?
Dr Kane says the heart has three layers called pericardium, myocardium and endocardium. He explains, “Usually, the virus can cause pericardial inflammation and the person can get chest pain, especially when coughing or breathing. And sometimes, the virus can spread to myocardium, the middle layer of the heart. We then call it viral myocarditis. Once you get myocarditis, the heart pumping capacity reduces, leading to severe breathlessness and congestion in the lungs. It can sometimes get very severe, even requiring ICU admission.”
Myocarditis causes different kinds of cardiac complications like irregularity in the heartbeat or tachycardia and heart failure. Dr Unnithan says that when young people come in with fever, increased respiratory rate and severe breathlessness, we find that it’s more of a heart problem than a lung problem. “These people have never had heart conditions before. That is when we realise that it could be viral induced myocarditis,” she adds.
Dr Kane says that after three months of infection, if it prolongs, we call it cardiomyopathy. “The recovery gets very difficult. One may have to live with low pumping capacity of the heart and follow measures that are taken for people with heart failure. But, that is an extreme form of presentation of viral flu,” he adds.
Flu and chest pain
Chest pain is not normal with only the flu unless it affects the muscles. “It could cause muscular pain, but heart attack pain is different and severe. As one may have similar pain when there is pericardial inflammation or myocarditis, it can be difficult to identify. We usually do tests like echocardiography to see if the heart muscles are affected,” says Dr Kane.
Can the flu cause high blood pressure?
Dr Kane says flu usually causes low BP.
People with already existing heart conditions are more likely to get severe problems as their heart function is already compromised. Dr Unnithan says they are more likely to get affected severely by the virus. “Usually, the virus is killed by our immune system much faster. But the immunity of people with chronic diseases is not strong and hence, they are at risk of getting more severe infections,” she says.
Precautions to prevent flu
Experts say one should avoid contact with people who have influenza. One must wash their hands regularly and the affected should cover their mouth when they sneeze as these viruses spread through the air and can land on surfaces of tables and chairs where they stay alive for long hours. If somebody else comes in contact with these surfaces, chances are high that they could also get infected.
Dr Kane says that one with already existing heart conditions and other chronic comorbidities like diabetes should be careful and take precautionary measures. He recommends annual vaccination for diabetics, especially for older people. “The chance of getting flu is reduced by 50 per cent if a person is vaccinated and if infected, the severity reduces by 50 per cent. They should take the vaccine every year, just before the flu season starts,” he says.
Takeaways
- In rare cases, the influenza virus can spread and affect the heart.
- When it affects the heart, it can cause inflammation of its muscles, affecting the heart pumping capacity.
- Symptoms could include breathlessness, palpitations and irregular heartbeats. Flu also causes low BP.
- If the infection progresses to cardiomyopathy, recovery can be very difficult.
- It is best to take necessary precautionary measures like avoiding contact with a person affected with flu and take annual vaccinations if one already has comorbidities.
