The heart is a muscle that is made up of the endocardium (the inner wall layer of the heart), the myocardium (the muscle of heart wall) and pericardium (outside layer of the heart). Myocarditis is an inflammation of the myocardium heart muscle.

Myocarditis is relatively uncommon and can be diagnosed in otherwise healthy people. It is the cause of up to 20% of sudden deaths in young adults.

If you get diagnosed with this, you will probably have a few different doctors come and ask you to repeat your story or symptoms as they try to pinpoint a specific cause. In the majority of cases however, the actual cause of myocarditis remains unknown.

It seems to be common among patients that myocarditis tends to follow bacterial or viral infections (eg flu) and in particular upper respiratory tract infections. Sometimes it can also be a severe side effect of (strong) medication.

Some symptoms can include:

• heart palpatations / irregular heart beat
• high pulse or heart rate "at rest"
• night sweats / cold sweats
• prolonged sensation of heartburn
• chest pains (squeezing/stabbing) that cannot be relieved by changing positions
• can be similar symptoms to a heart attack

1. Blood tests - when someone has a heart attack or the heart is damaged in any way, an enzyme is released into the blood stream (eg troponin). Doctors test for the presence of this enzyme, which is only found in the heart, as evidence there has been some damage to the heart muscle.
2. X-ray or Ultrasound (echocardiogram - "echo") or both- this is to examine the shape of the heart and analyse the flow of blood through the chambers. In myocarditis, the heart muscle is inflamed and appears larger than normal.
3. Electrocardiogram (EKG) - electrodes taped to your skin examine the electrical activity of the heart, highlighting if there is any irregular heart beat. Often they will monitor you for a few days if you stay at the hospital under observation - don't worry you won't be stuck in bed, it is a small mobile device that fits in your pocket. A Holter monitor.
4. Blood Oxygen Levels are measured by a small device placed over your finger. This just ensures that the oxygen in the arterial blood coming from the heart has an adequate amount of oxygen.
5. Treadmill Test - As a patient runs on a treadmill, more oxygen is required and blood pressure increases. An EKG attached during the test can show whether enough oxygen is being supplied to the heart.

As there is no specific cause of myocarditis, treatment often involves bed rest, no strenuous lifting or exercise and a low-salt diet (to keep the blood pressure down so the heart doesn't work as hard). Depending on the severity, some medication may be given to reduce the inflammation or to regulate the heart beat.

After a couple of months rest, most people recover fully from myocarditis. In rare cases, it can return. Essentially, when you catch the flu sometimes your back or arms ache. In myocarditis, it happens to be the heart muscle that is hit. Getting it again has been described by a doctor as being struck by lightning twice. The heart itself fully recovers when the inflammation goes away. It is not the same as a heart attack where the heart muscle is deprived of oxygen, killing some cells.

One case I know of involved a healthy 26 year old man that had a "bad run" one year during winter with flus and colds. The doctor prescribed 2 strong courses of 1000mg antibiotics - Augmentin - which appeared to do nothing for the infection. He was also working long hours as an engineer in a country town and probably just generally run down. No excessive alcohol was involved and he did not take any illicit drugs.

A few weeks later during dinner, the man experienced a cold sweat and rapid heart palpatations for no reason. Following this, a sensation of heartburn followed continuously for over a day but no relief was found from anti-acid tables or chamomile tea. Sitting or lying down in different positions also did not help the pain. Night sweats were also experienced.

After a couple of days of this, he went to hospital to have it checked out and after an ECG, X-ray, blood tests and an ultrasound, was diagnosed with mild viral myocarditis.

The only treatment for this was paracetamol for any fever and strict bed rest. No strenuous exercise. He was kept in hospital for a week for observation and then ordered time off work for a month after which a follow up ultrasound showed that the heart had returned back to normal size.