Growths in the heart (cardiac rhabdomyomas)

The growths in the heart that people living with TSC might develop are called cardiac rhabdomyomas. These growths can occur anywhere in the heart and are largest at birth, getting smaller over time before usually disappearing. Cardiac rhabdomyomas typically cause fewer problems as the infant grows up. While it is common for young infants and newborn babies living with TSC to have multiple cardiac rhabdomyomas, these rhabdomyomas do not spread through the body.

Cardiac rhabdomyomas can require regular monitoring and on occasion might require treatment and intervention. A few individuals with cardiac rhabdomyomas will have long-term problems with their heart rhythm and will need to be monitored throughout their lives. However, for the majority of people, cardiac rhabdomyomas rarely cause problems.

What are some of the symptoms of cardiac rhabdomyomas?

The symptoms associated with rhabdomyomas vary and depend on the size, number and location of the tumours within the person’s heart. Most newborn babies and infants with rhabdomyomas do not have any symptoms at all.

If a newborn baby or child has a large growth in one of the four chambers of the heart at birth, there is the possibility that it could obstruct the forward flow of blood, meaning that the heart is unable to pump enough oxygenated blood around the body. This can lead to the blue discolouration of the skin and lips (called ‘cyanosis’).

It is possible for cardiac rhabdomyomas to be so large that they could be life threatening, in which case partial or whole removal of the tumour could be an option. However, even when large cardiac rhabdomyomas are causing problems, a clinician may not recommend their removal. This is because the problems are likely to lessen and then improve as the child grows and the rhabdomyomas shrinks.

In about one in five patients, cardiac rhabdomyomas are located close to the heart’s electrical conduction system. This can result in abnormalities of heart rhythm that could cause the heart to beat abnormally fast or abnormally slow. These patients may experience palpitations, chest pain or fainting.

A few individuals will have long-term problems with heart rhythm that will need to be monitored throughout their lives. Some newborn babies with TSC may have very small growths (so small they could only be seen under a microscope) in the muscle fibres of their heart, which might reduce the strength of their heart muscle.

Problems with blood vessels

In rare cases, some people living with TSC may have problems with their blood vessels. These might be so mild that there are no symptoms, but can include:

• Narrowing of the aorta artery, which pumps oxygen-rich blood from the heart to the body
• Narrowing of the arteries which takes oxygen-rich blood to the kidneys
• Weakening of the aorta artery’s walls
• Hypertension (high blood pressure)

Monitoring of the heart

The number and range of scans that a person with TSC will receive to check on their heart will vary for every individual. Generally, when a diagnosis of TSC has been confirmed an echocardiogram (heart scan) and ultrasound is recommended, to see if the heart or blood vessels have been affected. This is particularly important for newborn babies and infants under three years of age who have been diagnosed with TSC.

The frequency of future scans will likely depend on the presence of abnormal growths, the heart’s rhythm (if it is beating in time) and if any general signs or symptoms of heart problems (such as palpitations or fainting) have been recorded.

People with heart growths will generally have an echocardiogram every 1-3 years until regression of the heart growths, whilst all people living with TSC should have an electrocardiogram every 3-5 years. If heart rhythm problems are significant, a clinician may suggest medication to help avoid issues resulting from it.