Bangungot also known as Sudden Unexplained Death Syndrome (SUDS)

Sudden unexpected death syndrome (SUDS) or Sudden unexpected nocturnal death syndrome (SUNDS) is sudden unexpected death of adolescents and adults during sleep. It is rarely observed in the Western world, and appears to occur more commonly among young men in East and Southeast Asian countries. While experiencing this, the person is aware that he is dreaming but feels like there is something that stops him from moving and awaking. It is also known as "Lai-Tai".

Sudden unexplained death syndrome was first noted in 1977 among Hmong refugees in the US. The disease was again noted in Singapore, when a retrospective survey of records showed that 230 otherwise healthy Thai men died suddenly of unexplained causes between 1982 and 1990: Publication of this data provoked a diplomatic incident.

In Thailand it is particularly believed to be linked to eating rice cakes. Filipinos believe ingesting high levels of carbohydrates just before sleeping causes bangungot.
It has only been recently that the scientific world has begun to understand this syndrome. Victims of bangungot have not been found to have any organic heart diseases or structural heart problems.
However, cardiac activity during SUDS episodes indicates irregular heart rhythms and ventricular fibrillation. The victim survives this episode if the heart's rhythm goes back to normal. Older folks in the Philippines recommend trying wiggling the big toe while experiencing this to snap back.
In the Philippines, most cases of bangungot have been linked with acute hemorrhagic pancreatitis, whereas in Thailand and Laos, bangungot (or in their term, sudden adult death syndrome) is caused by the Brugada syndrome.

The condition appears to affect primarily young Hmong men from Laos (median age 33) and northeastern Thailand (where the population are mainly of Laotian descent). There is a strong hereditary component and the victims tend to die in their sleep.
Survivors describe a feeling of intense fear and paralysis. There is a sensation of pressure in the chest, the presence of an alien being in the room and altered sensation.

The cause of this syndrome has been theorized to be a form of Brugada Syndrome.

It was noted very early on that the disease had the characteristics of a familial cardiac conduction defect (i.e., a problem with the electrical pathways of the heart). and one study has shown evidence for a long-QT syndrome in populations at risk. Thiamine deficiency is common in the risk population because of diet, and is also a cause of a prolonged QT-interval;[13] but proof that inducible ventricular arrhythmia is the cause of this disease came only with the publication of the DEBUT trial in 2003.

Ongoing genetic studies by Spanish electrophysiologist Dr. Josep Brugada Terradellas show that SUDS results from mutations in the cardiac sodium channel gene. This means that it is a chromosomal problem, which is why it runs in families. Thus, doctors say that families who have kin that have suffered from or died of SUDS must see a heart specialist.

The only proven way to prevent death is by implantation of a cardiovertor defibrillator. Oral antiarrhythmics such as propranololare ineffective.

This phenomenon is well known among the Hmong people of Laos, who ascribe these deaths to a malign spirit, dab tsog (pronounced "da cho"), said to take the form of a jealous woman. Hmong men may even go to sleep dressed as women so as to avoid the attentions of this spirit.
Every Filipino family knows someone who has been killed by the "bangungot." In Filipino folklore, bangungot is personified as a fat man who creeps into the bedroom of sleeping men and sits on their faces to suffocate them.
Bangungot is also depicted in the Philippines as a mythological creature called batibat. This hag-like creature sits on the victim's face so as to immobilize and suffocate him.

Bangungot (Philippines): The term originated from the Tagalog word meaning "nightmare." The root of this word comes from two Tagalog words bangon, which means to rise or to be awake and ungul which means to moan.

Dab tsog (Laos),
Laitai (Thailand), Pokkuri disease (Japan), hukuri-wikipedia