There are relatively few situations where cardiac emergencies can occur in a child. A special focus is directed to the cyanotic newborn. In these cases a very specific treatment plan is necessary which is limited to a few dedicated centres. The importance lies in the timely diagnosis of a cyanotic heart defect and the rapid and safe transport from the referring hospital. An outline is given on the causes and treatment of congestive heart failure in infancy. Management guidelines are given for the most frequent types of cardiac arrhythmias and the few occasions, where an arrhythmia can lead to a real emergency, mostly in infants. To complete the list of the most frequent cardiac emergencies in pediatrics, pericardial effusion/tamponade is mentioned as well as the occurrence of cyanotic spells typically in the baby with Fallot's tetralogy.