Aguero felt chest pains in Barcelona's LaLiga Santander match with Alaves, eventually leaving the field. Tests after the game revealed a cardiac arrhythmia. The Argentine was transferred to hospital for a cardiology examination on Saturday.
"He is unavailable for selection and, during the next three months, the effectiveness of treatment will be evaluated in order to determine his recovery process."
Norberto Debbag, an Argentine cardiologist, did though provide the public with an explanation on what a cardiac arrhythmia means for an athlete.
"An arrhythmia can be studied within 24 hours, the diagnosis will already be in place," Debbag explained to Ole.
"Ventricular ones are the most complicated because there is damage to the structure of the heart, whilst Atrial arrhythmias are more benign, which can be solved with medication.
"We have no details about Aguero but it won't take long to find out, just when he will play again will depend on the time of arrhythmia that is detected."