The sprinter had been training with his team-mates in Benidorm on Spain’s Mediterranean coast, when he noticed an anomaly in his heart-rate.
According to Ciro Scognamiglio of Italian sports newspaper La Gazzetta dello Sport, Viviani left the camp and contacted a cardiologist, who referred him to a hospital in Ancona, Italy for testing.
Cofidis has yet to confirm the reports publicly.
Viviani’s compatriot Diego Ulissi has already been forced to take a break from racing due to heart concerns.
The Italian had been strong throughout the 2020 season, winning two stages of the Giro d’italia and racking up a collection of victories.
But while undergoing off-season health checks required by the UCI, UAE Team Emirates doctors discovered abnormalities during Ulissi’s cardiac tests.
Dr Michele De Grandi said: “Diego underwent the normal health checks required by the UCI and the team. Subjectively he was fine and did not feel any disturbance, but the finding of an irregular heartbeat during a physical exertion, not previously present, gave us some doubt. Even with a normal ultrasound appearance, two new tests (Holter ECG 24 hours, which highlighted further arrhythmias, and a cardiac MRI scan) have drawn a conclusion of myocarditis.”
Myocarditis is an inflammation of the heart muscle and is usually caused by a virus.
Treatment can often involve medication, while people with myocarditis are often told to avoid exercise during recovery.
Ulissi, 31, said he will take a break from racing that he hopes is temporary, but is not sure when he will be back to competition.
Viviani, former European champion, is entering his second season with French WorldTour squad Cofidis after two seasons with Deceuninck – Quick-Step.
The 31-year-old is yet to cross the line first with his new team, but will be hoping to change that as he gets his season underway at the Volta a la Comunitat Valenciana on February 3.