A fatal case of a stressed newborn baby who developed tricuspid insufficiency due to an anterior papillary muscle infarction of the right ventricle, related to perinatal anoxia is reported. The baby needed resuscitation management and had a systolic murmur soon after birth. The echocardiographic examination showed a flail anterior leaflet of the tricuspid valve due to an avulsed anterior papillary muscle. There was rupture of chordae tendineae between anterior and posterior leaflet. Necrosis and calcium deposit were found in the area. The conclusion was that the anoxia in perinatal period, in most cases, causes transient lesions, but in few cases might be severe and fatal. It is important a complete cardiac evaluation in every case of prolonged perinatal stress.