Scary moment on the NHL ice Tuesday ... Blues star Jay Bouwmeester collapsed on the team's bench mid-game -- and was rushed to the hospital with what officials are calling a "cardiac episode."
The 36-year-old had just finished a shift early in the first period against the Anaheim Ducks in Southern California ... when something went horribly wrong.
You can see in on-ice video of the incident ... Bouwmeester appeared to pass out on the St. Louis bench -- and his teammates immediately called for help.
Reporters on scene say the defenseman -- who's played in the NHL since he was 19 years old -- was stretchered to the locker room and rushed to the hospital shortly after.