RecruitingDrug trialEfficacy, Safety, and Pharmacokinetics of Vericiguat in Pediatric Participants With Heart Failure Due to Left Ventricular Systolic Dysfunction (MK-1242-036)This study aims to compare the efficacy of vericiguat versus placebo on change in n-terminal pro-brain natriuretic peptide (NTproBNP) from baseline to Week 16 of the Base Period. The primary hypothesis is that vericiguat is superior to placebo in reducing NT-proBNP at Week 16 of the Base Period.