Final answer:
CPR should be started if an infant's heart rate is less than 60 bpm, as lower heart rates may indicate inadequate blood flow and the need for medical attention, particularly in the context of the Apgar score.
Step-by-step explanation:
CPR should be started if an infant's heart rate is less than 60 bpm. This is based on the understanding that lower heart rates in infants may not provide adequate blood flow and oxygenation to vital tissues and organs. In the case of bradycardia, which is the condition where the resting heart rate drops below 60 bpm, immediate medical attention may be required to maintain the infant's circulation and breathing.
.The Apgar score, used shortly after birth to assess the health of newborns, considers both heart rate and respiration critical measurements. Immediate medical attention is often necessary if an Apgar score is very low, signaling a potential emergency.