Danish soccer star Christian Eriksen is getting a "heart starter" implanted to his chest soon ... a big step toward ensuring he never suffers another terrifying cardiac episode again.

Denmark national team doctor Morten Boesen made the announcement Thursday ... saying after multiple exams on the athlete, specialists have determined the 29-year-old needs an implantable cardioverter-defibrillator.

"This device is necessary after a cardiac attack due to rhythm disturbances," Boesen said.

"Christian has accepted the solution and the plan has moreover been confirmed by specialists nationally and internationally who all recommend the same treatment."

As we previously reported, Eriksen went into cardiac arrest during last Saturday's Denmark vs. Finland game in Copenhagen ... and the scene was horrifying.

Eriksen collapsed on the pitch and needed a defibrillator to be revived ... and he's been in the hospital ever since.

Eriksen, though, has been in good spirits while recovering -- the soccer player posted an update from his hospital bed earlier this week saying, "I'm fine -- under the circumstances."

It's unclear if Eriksen will be able to play soccer again ... but he did make it clear he'll certainly be cheering on the Denmark team as it takes on Belgium on Thursday.