Ruth Kam Heart & Arrhythmia Clinic
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The heart doesn’t only suffer because of heart disease. There are many bacterial and viral diseases that affect the heart muscles and function. Here’s what you need to know.
Infections that get to the heart
The heart is an amazing organ – and one that is usually resilient to infections. We often hear about infections of the lungs, stomach, intestines, kidneys, liver, reproductive system, and even the brain, but not the heart. Yet the heart too can be invaded and afflicted with an infection. An infection anywhere in the body, if severe enough, produces enough toxins to affect all the organ systems, and even depress heart function.
A dangerous valve
In rare cases, bacteria from a distant site of infection, such as a skin or tooth abscess, may spread to the heart valves and create a ‘nest’ of bacteria and fibrin that destroys its tissues. This condition is called infective endocarditis and is a serious and life-threatening condition if not treated in time. The ‘nest of gunk’ resembles a coral, and is aptly called ‘vegetation’. Washed by the constantly flowing stream of blood through the heart valves, bits of this vegetation may break off and be carried to various organs, spreading the infection. In the brain, the vegetation may form abscesses or weaken the blood vessels. A later rupture will cause disabling or a fatal stroke. The infection can also lead to septic arthritis (swollen joints), abscesses in the organs or heart failure due to the destruction of the heart valves.
Myocarditis
This is inflammation of the heart muscle, or myocardium. There are various causes, but the most common are viruses, and it can affect anyone at any age. The viruses that cause the common flu, gastric or intestinal flu, mycoplasma, and legionella can all infect the heart by attacking the heart muscle, causing myocarditis. For instance, myocarditis can develop at the same time as, or just following, a viral throat or chest infection.
Other infective agents that can directly infect the heart in this way include bacteria, fungi or parasites. Less commonly, infections caused by animal-borne parasites spread by birds, cats and deer can affect even healthy individuals, but those most at risk are people with weakened immune systems. These include the HIV-positive, cancer patients and those on chemotherapy, organ transplant recipients, and people with autoimmune disorders (e.g., rheumatoid arthritis, systemic lupus erythematosus) and intravenous drug abusers.
An attack after the fact
Some infections such as rheumatic fever or Chaga’s disease may cause damage to the heart slowly, long after the infection has subsided. Rheumatic fever, caused by the streptococcus bacteria, starts off with a throat or skin infection. When the body sends out its ‘army’ of antibodies to fend off the infection, some of these antibodies may cross-react with the body’s own tissues and become deposited in the heart valves. The immune system attacks these complexes and damages the tissues in a ‘friendly crossfire’. Over time, the heart valves become deformed, excessively narrowed or leaky, causing heart enlargement and failure. Timely valve surgery to enlarge the valve or replace it with a prosthetic may avert these complications.
In Chaga’s Disease, a bite from bloodsucking “kissing bugs” may lead to a parasite being deposited into the wound and the blood stream. The infection that results may cause short-term fever, headache and swollen glands. The real damage comes later; these parasites infect the heart muscle, esophagus, stomach and intestinal cells, multiplying in the cells and destroying them. When the immune system steps in, it attacks the organ itself. Chaga’s disease can cause heart enlargement, heart failure and fatal arrhythmias. In the digestive system, it can lead to enlargement of the stomach and intestines, causing maldigestion and malabsorption resulting in severe malnutrition.
Depending on the cause and severity of the infection and its effect on the heart, there are sometimes no symptoms. Many people with viral myocarditis, for instance, do not have any heart-related symptoms. On the other hand, there are symptoms such as fever, chest pain, faster than usual heartbeat, breathlessness and tiredness that may be cues.
If the inflammation damages the heart muscle or the fibres that conduct the electrical impulses in the heart, complications such as loss of consciousness, a heartbeat that is unusually fast, slow or irregular, or heart failure can arise.
All this underscores the importance of ensuring proper rest and medical supervision during an infection, and being alert to symptoms, which vary depending on the cause and severity of the inflammation.
DR RUTH KAM
Cardiologist
MBBS (Singapore)
MRCP (Int Med) (UK)
M Med (Int Med) (Singapore),
FAMS (Cardiology), FRCP (Edin)
Ruth Kam Heart and Arrhythmia Clinic
1 Farrer Park Station Road, #07-11 Connexion
Farrer Park Medical Centre, Singapore 217562
Tel: 6443 0468
www.arrhythmia.com.sg