A Barcelona statement said: ‘The player has undergone a diagnostic and therapeutic process by Doctor Josep Brugada and will be out of action during the next three months as the effectiveness of treatment is evaluated.’

The 33-year-old spent Sunday and Monday in hospital in Barcelona as extensive cardiac tests were carried out

The Argentine striker, who joined on a free transfer from Manchester City in the summer, felt pain in his chest after jumping for the ball up against Alaves defender Victor Laguardia in the first half of their 1-1 draw on Saturday night.

LA preliminary diagnosis suggested he was suffering from heart arrhythmia. The former Manchester City striker asked to be taken off after 40 minutes of Barcelona’s draw with Alaves on Saturday night complaining of chest discomfort.

He was taken straight to the hospital in an ambulance to receive a medical check-up after being replaced by Philippe Coutinho three minutes before half-time.

On Monday night, the striker tweeted: ‘I am fine and in good spirits to face the recovery process. I want to thank everyone for so many messages of support and affection that make my heart stronger today.’

Aguero was making his first start at the Nou Camp since his summer transfer.

In a six-page letter to the South American confederation, Argentina complained that VAR was not used to check two decisions that could have lead to penalties for fouls on Sergio Aguero and Nicolas Otamendi.

Aguero appeared to be fouled by Dani Alves during the game, and Argentina were unhappy after no penalty was awarded when Otamendi went down in the box following a challenge from Arthur.

Brazil won the game 2-0 thanks to goals from Gabriel Jesus and Roberto Firmino, and following the game Argentina forward Lionel Messi blamed the defeat on the performance of Zambranol.

This was City’s 13th consecutive league victory as they ended what has been incredible season with 98 points. Goals from Agüero (28), Laporte (38), Mahrez (63), Gündogan (72) saw City come from behind after Glenn Murphy took the lead in the 27 minutes of the game.

City has now become the first team to retain the Premier League trophy since Manchester United last did it in 2009.