- Baseline evaluation of cardiac function should be performed at the confirmation of the diagnosis or at latest by the age of six years. Minimum evaluation should include an electrocardiogram (ECG) and echocardiogram.
- Evaluation of cardiac function should occur at least once every two years until the age of ten. Yearly complete cardiac evaluations should begin at approximately ten years of age or at the onset of cardiac signs and symptoms, if earlier. If noninvasive cardiac tests show abnormalities, increased surveillance is required, at least every six months, and drug treatment should be initiated.