The presentation makes the case that none of the three, 1) arrhythmia, 2) stress (mentioned by Fuddy's Deputy) and 3) hyperventilation were even possible to be viewed at autopsy.
At the close of the autopsy's (claimed) viewing of the body, the Medical Examiner said that pending toxicology reports, the tentative Cause of the Death was drowning.
Drowning as a Cause of Death is not some last possibility to be crossed off some list. For a Medical Examiner (ME) to make such a statement means there was positive evidence of drowning, typically evidence of the involuntary inspiration of ocean water (in this case) accompanied by specific histological changes indicative of oxygen starvation, such as acute congestion and swelling of the capillary endothelia or over-distension of the alveoli, to make that assertion. To claim drowning without such positive evidence is likely irresponsible, if not possible malpractice (though one should indeed hear more completely what the ME has to say in her defense of this).
The ME was not known to have interviewed the plane's occupants, but it's rumored she got the passenger information via the NTSB.
And yet... by the time the autopsy report was filed, there was only a mention of these fleeting, invisible mentions on other passengers' lips of stress and hyperventilation that somehow were able to overcome the positive evidence stated to have been present at autopsy--while viewing the body.
The NTSB story about Ms. Fuddy wearing only a partially-inflated infant life jacket has been debunked via video imagery that shows Ms. Fuddy wearing an unmistakable adult life jacket on which both upper and lower chambers were filled, indicated both CO2 cartridges had been expended.
That's quite something.
It would seem claims of stress, hyperventilation, infant life jackets and horrible 6-to-8-foot waves are the stuff of a concerted plan, rather than reality.
Then there are the images of Ms Fuddy and her unique-and-curvy (5'2", 220#) figure and shoes, compared to another male figure (6'+ and 170#) with very different shoes and a red wig a mere 37 seconds later.