Trimetazidine: Drug banned by WADA makes 'your heart work more efficiently'

Controversy surrounding Russian figure skater Kamila Valieva's failed drug test, which was taken in December but has only come to light during the Winter Olympics in Beijing, continues to delay the medal ceremony of the figure skating team event.

On Friday, the International Testing Agency (ITA) confirmed that Valieva had previously tested positive for the banned heart drug trimetazidine, commonly used to treat people with angina.

Kamila Valieva: Russian anti-doping agency allowed teenage figure skater to compete in Olympics despite failed drug test

The failed test only came to light during the Winter Olympics and after Valieva and the Russian Olympic Committee (ROC) won gold in the figure skating team event ahead of the USA and Japan. It remains unclear if the gold medal will be revoked.

The case will be heard by the Court of Arbitration for Sport (CAS), with a decision needed before Valieva's next event -- the women's singles short program -- on Tuesday, in which she is favorite to take gold.

In that hearing, the International Olympic Committee (IOC) will challenge a decision by the Russian Anti-Doping Agency (RUSADA) to lift a provisional suspension on Valieva, according to the ITA.

Nathan Chen reacts to winning his first Olympic gold 02:25

Responding to the controversy, the ROC said Valieva had "repeatedly passed doping tests" while already in Beijing, adding that it is taking measures to keep Valieva's "honestly won" gold.

What is trimetazidine?

According to the European Union's medicines agency (EMA), trimetazidine "is a medicine used to prevent angina attacks, which are sudden pains to the chest, jaw and back brought on by physical effort, due to reduced blood flow to the heart."

It is listed in the World Anti-Doping Agency's (WADA) 2021 prohibited substances under the category of "hormone and metabolic modulators," a class of drugs that have been banned by WADA due to evidence of athletes using them for performance enhancement.

"This is an interesting choice to be used in this way because I think a lot of times, people might think: to enhance your performance, you'd use a stimulant or something that would increase your heart rate or get your metabolism going," Dr. Elizabeth Murray, paediatric emergency medicine physician at the University of Rochester Medical Center, told CNN's Early Start program on Thursday.

"But what this drug does is actually make your heart work more efficiently. It doesn't change your blood pressure very much or change your heart rate.

"An athlete wouldn't get jittery or necessarily feel all that different, but they would theoretically be able to perform at a higher level for longer. It would increase their endurance, potentially."

The Winter Olympics in Beijing run from February 4-20

The most famous case of doping involving trimetazidine is Chinese swimmer Sun Yang, who was handed a three-month suspension in 2014 after testing positive for the drug.

Banned metabolic modulators have been used by cyclists, weightlifters, boxers, wrestlers, skiers and other athletes from dozens of countries including Russia, Poland, Columbia, Belgium and Germany.

According to Dr. Murray, trimetazidine would not normally be given to children "unless there's a very good reason."

What happens next?

The ITA, which leads the anti-doping program for the Beijing Winter Olympics, said Valieva's drug sample was taken at the Russian Figure Skating Championships in Saint Petersburg on December 25.

However, it took until February 8 for a laboratory in Sweden to report it had detected a banned substance -- one day after the ROC won gold at the team event in Beijing.

Valieva was immediately given a provisional suspension by Russia's anti-doping agency, which automatically prohibits athletes from participation in all sports.

She challenged the suspension on February 9 and, at a hearing that same day, the Russian anti-doping agency decided to lift the provisional ban -- allowing Valieva to continue competing at the Olympics, according to the ITA.

Hear what athletes think of fake snow at Olympics 02:50

IOC spokesman Mark Adams said on Friday that the governing body wanted to "expedite" the case.

"We hope that the whole issue can be expedited in the interest of every athlete, not just the Russians, but also in the interest of all of the athletes competing," said Adams.

What has Russia said?

On Friday, Kremlin spokesman Dmitry Peskov said there was a "misunderstanding" over Valieva's positive test as he offered support for the figure skater and the IOC.

"We have great respect for both WADA and the IOC," Peskov told reporters on a conference call.

"They are dealing with this situation at the moment. Let's not rush, let's wait for the completion of the proceedings and the decision of the IOC. For now, we all support our Kamila Valieva and wish her success."

Visit CNN.com/olympics for more news, videos and features

Peskov continued: "In any case, we absolutely and fully support our Kamila Valieva. We urge everyone to support her. And we say to Kamila: 'Kamila, don't hide your face! You are Russian! Walk proud everywhere you go and, most importantly, keep performing and winning!'"

Russian athletes are unable to compete in the Olympics under their country's name due to sanctions from the IOC and WADA as a result of the country's "systemic manipulation" of anti-doping rules during the 2014 Sochi Games.

In February 2021, the IOC announced Russian athletes would compete as neutrals under the ROC acronym at the Tokyo 2020 and Beijing 2022 Olympics.