The 30-year-old, who was born in Uzbekistan's capital Tashkent and represented the country of her birth before switching to the United States in 2007, provided a sample which failed for the heart attack drug on January 7 of this year, at the Brisbane International tournament in Australia.

She also tested positive during out of competition testing on March 1 and April 7, leading to her being charged and provisionally suspended by the International Tennis Federation (ITF) on March 12.

Her case is another to be affected by the confusion surrounding meldonium, which the World Anti-Doping Agency (WADA) only added to its banned list from January 1.

Question marks on how long the substance stays in the human body have led to clarifications and revisions of the rules from WADA, with Lepchenko claiming that her positives came because of a course of mildronate tablets that she stopped taking on or around December 20 in 2015.

She made a successful appeal to the chairman of an independent tribunal established to hear her case on April 13, following a notice issued by WADA on meldonium.

This saw her suspension lifted, with a second WADA notice on June 30 then advising the ITF that the concentrations found in Lepchenko's sample were consistent with her account of use prior to January 1.

Lepchenko's results in Brisbane, where she reached the quarter-finals before defeat to Spaniard Carla Suárez Navarro, have still been declared void and her prize money has been forfeited. 

"Varvara Lepchenko has been found to have committed an anti-doping rule violation under Article 2.1 of the Tennis Anti-Doping Programme," an ITF statement said today.

"It has been accepted by the ITF that Ms. Lepchenko bore no fault or negligence for the violation, and that any period of ineligibility that may otherwise have been imposed is eliminated."

A number of other athletes across a variety of sports have claimed that their failures for meldonium - which is developed in Latvia and is said to boost endurance - came despite not taking the substance after January 1.

The World Anti-Doping Agency (WADA) has received criticism for the advice it has issued on the drug, particularly from Russia, a country which saw a number of its athletes fail tests.

The most high profile of these was tennis superstar Maria Sharapova, who is currently serving a two year ban.

The five-time Grand Slam winner admitted to using the substance after it was banned, but claims she took it for health reasons stretching back to 2006.

She will find out in the first week of October whether her sanction will be reduced by the Court of Arbitration for Sport.