Sources:
https://www.berliner-zeitung.de/news/raetselhafte-herzerkrankungen-im-fussball-li.193554
The article lists a large number of recent cases of footballers who have had heart problems or collapsed on the field, in some cases leading to death.
That list is republished here;

As we previously highlighted, other professional athletes have also recently suffered similar health problems, including 24-year-old Slovak hockey player Boris Sádecký, who tragically died after collapsing on the ice during a match last Friday.