Table 2 Clinical indications for exclusion of BTHS

Consider routinely

· Fetal Cardiomyopathy

· Male children with DCM ± EFE, especially those with neonatal / infantile onset

· X-linked cardiomyopathy of any type (DCM, LVNC, HCM)

· Cardiomyopathy with LVNC or LV modeling defects

· Cardiac arrest / cardiac arrhythmia with echocardiographic abnormality consistent with BTHS

Consider with relevant accompanying features e.g. X-linked family history, growth failure, feeding problems, delayed motor milestones, lethargy/easy fatigue:

· Multiple male miscarriages / stillbirths / unexplained deaths

· Neonatal / infantile hypoglycaemia / lactic acidosis

· Viral cardiomyopathy

· Unexplained neutropenia, mitochondrial disease or proximal myopathy

· Serious unexplained bacterial sepsis

· Severe feeding problems, persistent episodes of vomiting / diarrhoea

· Growth failure / delayed puberty / delayed bone age

· Unexplained ventricular arrhythmia or prolonged QTc interval