- Patients greater than 6 months of age must have 2 of the following: a) Cardiomyopathy, defined as a LVMI determined by cross-sectional echocardiography; b) a requirement for invasive or non-invasive ventilatory support, where non-invasive ventilation is defined as any form of ventilatory support applied without the use of an endotracheal tube; OR c) Severe motor delay, defined as failure to perform gross motor skills achieved by 90% of normal aged peers on the Denver Developmental Assessment;