<prompt> Most common cause of fatal ventriculomegaly is ?Arnold Chiari Malformation - IArnold Chiari Malformationalformation - IIAqueductal StenosisDandy Walker Malformation  <response>: Most common cause of hydrocephalus and ventriculomegaly is aqueductal stenosis. Ventricles develop early in pregnancy and can be seen on a a minor self-limiting imbalance in fluid circulation and absorption that becomes compensated defects in brain development damage or loss of brain tissue Reference: GHAI Essential pediatrics, 8th edition 