The club said: “Following a cardiac exam, Barca striker Aguero has undergone a diagnostic and therapeutic procedure with Dr. Josep Brugada today.
“Over the next three months the effectiveness of the treatment will be evaluated to determine when he can come back.”
Aguero has made five appearances for Barca since joining on a free transfer from Manchester City this summer, his only goal for the side coming in the final moments during their 2-1 defeat against Real Madrid in El Clasico.
The situation with Aguero compounds issue at Barca, who are being overseen by interim coach Sergi Barjuan following last week’s sacking of Ronald Koeman. Sources have told ESPN that Barca are in talks to appoint club legend and now-Al Sadd coach Xavi Hernandez.