"Hyron's death was found to be caused by an aortic dissection. This dissection most likely occurred on an aortic aneurysm," Johannesburg-based Lions said in a statement on their website.

The statement added that the French authorities who carried out the autopsy on the 31-year-old found the cause of death to be "a tear in the aorta (due to natural causes), which led to a significant accumulation of blood within the sac surrounding the heart".

Andrews was found in cardiac arrest in a shower cubicle that was locked from the inside last Friday, on the eve of his team's meeting with La Rochelle.

Despite the tragedy, Lions played their debut Champions Cup match, losing 31-14 on Saturday.

The match was marked by a minute's silence during which all the players and substitutes lined up in front of a Lions jersey bearing Andrews's number 5.

A spontaneous wave of applause in his memory also swept through the Marcel Deflandre Stadium in the fifth minute.

Andrews had only returned to his native South Africa earlier this year after a two-year spell with English Prem side Sale Sharks. He began his career with the Sharks franchise in Durban and represented his country at Under-20 level.

Lions said that Andrews's body is still in France and that the "timeline for the return of Hyron's body to South Africa has not yet been determined".