I forget that many people don't know terms I'm using that become a second language in the NICU neighborhood and I was just asked what a brady was...
For infants, bradycardia (brady) is defined as when the baby's heart rate slows down to less than 100 beats per minute (normal is around 120-160 beats per minute). Premature babies have apnea and bradycardia spells more often than full-term babies, It's not clearly understood what causes these spells. Some researchers think the spells are related to centers inside the brain that regulate breathing and that may not be fully developed. Touching your baby gently or rocking the incubator slightly will almost always get the baby to start breathing again, which increases the heart rate. Medications (theophylline or caffeine) can be used to treat these spells in babies if necessary. NICU standard practice is to electronically monitor the heart and lungs for this reason.
Apnea is a technical term for suspension of external breathing.
They will also often call them A's & B's for apneas & bradies.
EDIT - For more term definitions that I'll probably be using here is a great website: http://www.ttmf.org/glossary.html