Table 2.

Clinical indications for exclusion of BTHS

Recommendations for exclusion of BTHS	Clinical scenario
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