Hi Sandra, Welcome to HealthcareMagic Forum.
Your child is having Hypothermia (Normal Body temperature should be between 96.8 to 98.6 deg Fahrenheit) as a result of Poor Blood Perfusion secondary to Atrial Flutter
. There are various causes for this in Infants like, Congenital Heart Disease. It has to be confirmed via Transthoracic echocardiography
. He needs a Immediate evaluation as he may require radiofrequency ablation
or electrical cardioversion
. Speak to your Doctor at the earliest.