El‐Saiedi 2013.

Study characteristics
Methods	Randomised, placebo‐controlled, single‐centre study; table block randomisation stratified by clinical centre. No blinding reported.
Participants	86 patients (range 4 months to 6 years of age; mean age of 2.1 ± 1.3 years in the IVIG group versus 3.3 ± 1.9 years in the placebo group) with acute‐onset dilated cardiomyopathy, LVSF less than 20%, less than 6 months duration of cardiac symptoms at time of randomisation. Exclusion criteria: neonates, history of cardiac symptoms since birth
Interventions	Treatment of 1 g/kg IVIG (VIGAM‐S. , 2.5 g and 5 g, Bio Products Laboratory Limited) each day for 2 consecutive days versus regular glucose 5% IV fluids 10 mL/kg repeated on 2 consecutive days
Outcomes	Primary endpoint was change in LVSF and LVEDD from baseline to 6 months post randomisation assessed by echocardiography. Secondary endpoint was survival versus death.
Notes	Funding: not reported Language of publication: English
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Used a "random table block stratified by clinical center"
Allocation concealment (selection bias)	Low risk	Third party managed group assignment.
Blinding (performance bias and detection bias) All outcomes	Low risk	Placebo used, and both groups received the same follow‐up.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	All participants received the same follow‐up; survival vs death was hard endpoint.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Number of participants lost to follow‐up was not reported.
Selective reporting (reporting bias)	Unclear risk	Insufficient information reported; data on SF are shown in Figure 2, but numbers are not provided.