This clinical trial is focused on studying a condition known as Heart Failure due to a specific problem with the heart called Left Ventricular Systolic Dysfunction. This condition affects the heart’s ability to pump blood effectively. The study involves a treatment called Vericiguat, which is being tested to see how safe and tolerable it is for children with this type of heart failure. Vericiguat is available in two forms: a tablet and an oral suspension, which is a liquid form that can be swallowed.

The purpose of this study is to monitor the safety and tolerability of Vericiguat, also known by its code name MK-1242. Participants in this study will have previously been part of an earlier study and will continue to receive Vericiguat. The study will observe participants over a period to see if they experience any side effects or need to stop the treatment due to any adverse effects. The study will also look at changes in a specific heart-related protein in the blood, known as N-terminal pro-brain natriuretic peptide (NT-proBNP), which can indicate how well the heart is functioning.

Participants will take Vericiguat by mouth, either as a tablet or a liquid, for a maximum period of 108 weeks. The study aims to ensure that the treatment is safe and well-tolerated by the participants. This trial is an extension of a previous study, allowing researchers to gather more information about the long-term effects of Vericiguat in children with heart failure due to left ventricular systolic dysfunction.