South Carolina Personal Trainer Elena Moore's Cause of Death Revealed, Watch Live

Elena Katherine Moore's cause of death is about to be announced by local authorities in South Carolina ... and TMZ is streaming live.

The Lexington County Coroner's office announced that officials will reveal the cause and manner of the personal trainer's death. You may remember, Elena was found dead in June about a week after she went missing.

A county spokesperson says Elena died from complications of cardiac dysrhythmia and premature ventricular contractions. It's considered to be natural causes.

Elena had a blood alcohol content of .089 during the autopsy -- though the spokesperson says it's unclear how body decomposition may have affected that number. She did not test positive for heart medication she was supposed to be using.

Days before Elena went missing, the spokesperson says she was taken to a hospital where it was determined she was suffering a full mental health breakdown. She was put on an involuntary psychiatric hold.

She's held in a medical facility until June 11 ... a total of 5 days. She's then released, and the spokesperson says Bannon Slice -- Elena's husband -- was contacted. Medical professionals put her in a cab, and she ended up stopping at a CVS where she procured 4 bottles of wine and a bottle of water.

Worth noting ... Slice is not now and has never been considered a suspect in the case, the spokesperson also notes. In fact, the spokesperson is making a point to say her husband tried to help her navigate her physical and mental health challenges.

The spokesperson notes she had an irregular heartbeat and was also diagnosed with several mental health issues, including anxiety.

Elena disappeared after leaving a Planet Fitness and heading toward a wooded area. Her husband reported her missing the following day.

Days later, authorities found a body wearing clothes similar to Elena's ... and they later determined it was her. She was 39 years old.

An autopsy was completed shortly after her death ... which investigators say revealed no bruising, cuts, gunshot wounds, stab wounds, blunt-force trauma, strangulation, or other external injuries.

We spoke to a friend of Elena's, who says she was acting paranoid in the weeks leading up to her death. She also shared a series of cryptic posts that seemed to indicate she was having issues with someone in her life.