Mexican Autopsy Reveals New Details on Treadmill Death of Facebook COO Sheryl Sandberg's Husband

There are major revelations about the death of Facebook's Sheryl Sandberg's husband.

The just-released autopsy reportedly says silicon valley exec Dave Goldberg had heart arrhythmia, an irregular heartbeat, which could have been a factor in his falling off a treadmill and hitting his head while on vacation in Mexico.  

Forensic scientist Dr. Lawrence Kobilinsky told INSIDE EDITION: It's interesting that the autopsy report did indicate an arrhythmia, I kind of thought that would be the case because this one of the leading causes of instant death."

INSIDE EDITION's Steven Fabian also spoke to pathologist Dr. Bill Manion.

Fabian asked, "Could the heart arrhythmia cause someone to be so dizzy that he would fall down?"

Manion explained, "Absolutely. Yes absolutely. They would feel faint, get pale, pale in color pale in the face, light headed, dizzy, and could easily fall down."

Details about what happened to Dave Goldberg when he was exercising on a treadmill have been sketchy until now, leading to wild speculation on the internet about what caused his death.  

But what we've learned is shedding more light on the mystery.

The luxurious Palmasola resort in Punta Mita, Mexico is where authorities now confirm Goldberg and Sandberg were vacationing.  

READ: Is James Bond Costing Mexico City $24 Million?

It features beachfront villas that rent for $11,500 a night.  Each villa has its own small private gym with a treadmill and weights.

That may explain why Goldberg wasn't discovered for several hours after he went to work out.

Kobilinsky added, "If people are exercising, it's good to have a partner near by. It's good to do it in a public gym rather than a private, secluded place, so that if you need help you can get it quickly."

WATCH: These 3 Steps Can Help You Avoid Injury or Death on a Treadmill

Sheryl Sandberg has now taken to Facebook, posting photos with her late husband along with a moving statement:

"Even in these last few days of completely unexpected hell, the darkest and saddest moments of my life, I  know how lucky I have been. If the day I walked down that aisle with Dave someone had told me that this would happen, that he would be taken from us all in just 11 years, I would still have walked down that aisle."

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