The Inter midfielder fell to the ground with no other player around him shortly before half-time in the goalless Group B clash in Copenhagen.
Eriksen's team-mates and referee Anthony Taylor called for immediate help from medical officials, who raced onto the pitch to treat the 29-year-old.
The players formed a protective barrier around Eriksen while efforts were made to resuscitate him.
Players from both teams were in notable distress on the field, as were supporters watching from the stands.
Taylor was seen consulting with both coaches, before the players were led from the pitch at the Parken Stadium in Copenhagen.
UEFA then confirmed the match had been suspended "due to a medical emergency".