In this randomised , double-blind , placebo-controlled trial , boys from three centres in the USA aged 7 years or older with Duchenne muscular dystrophy , myocardial damage by late gadolinium enhancement cardiac MRI and preserved ejection fraction received either eplerenone 25 mg or placebo orally , every other day for the first month and once daily thereafter , in addition to background clinician-directed therapy with either angiotensin-converting enzyme inhibitors ( ACEI ) or angiotensin receptor blockers ( ARB ) .