Sonny Colbrelli returned to his native Italy after collapsing on the first day of the Volta a Catalunya and spending nearly a week in a Catalan hospital.

The Bahrain Victorious rider was considered stable enough to be transferred to his home country on Saturday.

He will undergo further tests at an Italian medical facility on Monday to determine the cause of his irregular heartbeat.

"Sonny Colbrelli returned to Italy yesterday from Girona University Hospital. Due to his stable medical condition, Sonny Colbrelli was given permission to travel to Italy.

"The rider, who collapsed shortly after the first stage of the Volta a Catalunya, was given immediate first aid and then taken to the hospital for tests to determine the cause of an unstable arrhythmia that required defibrillation.

"Further tests will be performed in the coming days at the Italian Center of Excellence for the diagnosis and treatment of cardiovascular diseases.

"Until then, everyone at Team Bahrain Victorious wishes Sonny a speedy recovery surrounded by the love of his family."

Colbrelli collapsed after finishing second in the uphill sprint of the opening stage of the Volta on Monday. He was immediately treated by medical personnel and left the scene by ambulance 45 minutes after the finish.

Bahrain Victorious later confirmed that Colbrelli was suffering from an unstable arrhythmia that required defibrillation.

Initial tests showed "no signs of concern," but subsequent tests were "inconclusive" as to the underlying cause of the incident.