Critical congenital heart defects (CCHDs) are serious malformations that remain to be
an important cause of neonatal mortality and morbidity. The clinical presentations of CCHD are
shock, cyanosis, or respiratory distress, which may be similar to that of other neonatal conditions.
Failure to diagnose these conditions early on after birth may result in acute cardiovascular collapse
and death. Screening with routine pulse oximetry is efficient in distinguishing newborns with
CCHD and other hypoxemic illnesses, which may otherwise be potentially life-threatening. If the
cardiovascular system cannot be observed by echocardiography, then treatment with continuous
prostaglandin-E1(PGE1) infusion should be started in any newborn whose condition deteriorates in
the first few days of life. This review aims to provide a concise summary of the presentation and
management of various CCHDs and to emphasize the role of timely diagnosis in the management.