The fourth heart sound (S4), also known as the “atrial gallop,” occurs just before S1 when the atria contract to force blood into the left ventricle. If the left ventricle is noncompliant ...

Hydrocephaly is a related complication in individuals with Dandy-Walker due to cysts that form in the brain's fourth ventricle and block the flow of cerebrospinal fluid (CSF). This blockage allows ...