Testing of the heart using echocardiography is performed to visualise cardiac rhabdomyomas, the most common primary cardiac tumor of tuberous sclerosis complex (TSC) in infancy and childhood. The incidence of these tumors in TSC has been reported to vary from 47 percent to 67 percent. Childhood tumor regression is the rule. In other words, in most cases, cardiac tumors are their largest at birth and may shrink or disappear as the individuals grow older. A second peak in the incidence of these tumors may occur during puberty. Electrocardiograms (EKGs) are used to detect abnormal heart rhythms or arrhythmias. Any symptoms should be monitored by a cardiologist who is aware of the risks involved for individuals with TSC.
Cardiac rhabdomyomas are more likely to be the cause of heart failure in a newborn infant or young child than in an adult with TSC. Most rhabdomyomas of the heart are asymptomatic, but they should be treated by an experienced cardiologist if an arrhythmia or other cardiac problem is present. Cardiac arrhythmias infrequently have developed in children just after starting carbamazepine (Tegretol), used for the treatment of epilepsy. Reports have also shown a significant increase in the size of cardiac rhabdomyomas in infants with TSC with infantile spasms who are treated with adrenocorticotropic hormone (ACTH). Therefore, echocardiograms and EKG baseline measurements should be obtained before initiating these treatments.