A full-body MRI scan detected a heart issue, which saw the 52-year-old undergo an emergency surgery in order to have a tube fitted. The procedure, which would usually take 40 minutes, instead lasted for nearly three hours due to complications, as per Diario AS.
Carlos has been kept in hospital under observation for 48 hours, but has taken to social media to update concerned fans on reports suggesting that he suffered a heart attack.
He posted on Instagram: "I would like to clarify recent information that has been circling. I recently underwent a preventative medical procedure, planned in advance with my medical team. The procedure was successful, and I am well. I did not suffer a heart attack.
"I am recovering well, and looking forward to returning to full fitness and resuming my professional and personal commitments soon. I sincerely thank everyone for the messages of support, care, and concern. I would like to reassure everyone that there is no cause for concern. My heartfelt thanks go to the entire medical team who took care of me."
The Brazilian was inducted into GOAL's Hall of Fame earlier this month.