Russian investigators said Cherepanov suffered from chronic ischemia, a medical condition in which not enough blood gets to the heart or other organs.
Pavel Krasheninnikov, who sits on the Russian Hockey Federation's supervisory council and is a member of the State Duma, said there was no ambulance on duty at the arena where Cherepanov's Russian team, Avangard Omsk, was playing.
He asserted that emergency workers took too long to respond and didn't have a defibrillator, a machine used to shock the heart. It was unclear how much time it took paramedics to respond.
"There are elements of negligence here," Krasheninnikov said in televised comments.
Moscow regional investigator Yulia Zhukova said officials would look into why Cherepanov was playing with ischemia, and said officials could open a criminal investigation.
Former Rangers captain Jaromir Jagr played a shift with Cherepanov and was talking to him on the bench shortly after they left the ice, when Cherepanov suddenly collapsed, said a Rangers spokesman who talked to Jagr.
There was no collision that preceded the collapse, the spokesman said, but few other details were available. Cherepanov scored the first goal of the game and had eight in 15 contests this season, his third with Avangard Omsk.
"It was really kind of a surreal thing for the players," Cherepanov's agent Jay Grossman said. "He was skating in on a 2-on-1 with Jaromir and then they came back to the bench. Jaromir was talking to him and he told him he has to score on that play.
The next thing you know, he collapsed.
"(Jagr) went with him into the dressing room area and they revived him for some time and then he didn't make it," Grossman said.
Amateur video taken at the game showed players and coaches gathered around the Avangard bench, then carrying a player who appeared to be Cherepanov.
Grossman said Monday that testing done on Cherepanov at the NHL combine before last year's draft didn't reveal any heart problems.
He has been told that players in the KHL receive regular heart and blood tests, similar to those given in the NHL.
The Rangers announced Cherepanov's death shortly before they played at home against the New Jersey Devils on Monday night. New York coach Tom Renney said his club was not aware of any health issues with the young player.
"He's a Ranger and I think it'll have an impact on people," Renney said. "We're going to have to deal with it in our own personal way."
Cherepanov surprisingly slipped to the Rangers during the 2007 NHL draft and they grabbed him with the 17th pick. The talented forward dropped because of concerns about his signability and the potential difficulty in getting him to leave Russia.
"He was an exceptionally talented kid," Grossman said. "He played in the Russian Elite League, in the men's league, even before he was drafted which in and of itself is an achievement. He was a self-motivated kid that had an inner-confidence about him."
The Rangers maintained a good relationship with Omsk and the club's general manager, even though there has been feuding between the NHL and Russia's KHL.
New York assistant coach Mike Pelino recently returned from a one-week trip to Russia where he watched Cherepanov play and then dined with him and Jagr.
"I was shocked when I heard. I thought it must be a misprint or something because he just had so much going for him," Pelino said.
"He was someone who I was really excited about and thought, 'Wow, we did get something special here.' "He had things to work on. We felt he had to become a little stronger still, he had to probably become a little bit more aware defensively. But as far as raw talent went and the ability to score, he was great."
