SUNDS: Hidden danger that strikes without warning during sleep

About the sudden passing of Channel 8 journalist and news anchor Natthawut Ponglangka, who died unexpectedly in his sleep, Asst Prof Dr Sirin Apiyasawat, cardiologist at the Department of Medicine, Faculty of Medicine Ramathibodi Hospital, Mahidol University, has previously written an article explaining the condition commonly known in Thai as “lai tai”.

The condition, which has been linked to several high-profile cases, including the late comedian Waew Jokmok, sister of well-known comedian Mum Jokmok, is medically classified as Sudden Unexplained Nocturnal Death syndrome (SUNDS). It is reportedly found more frequently in parts of the Northeast of Thailand. Its danger lies in the abrupt and silent onset, with victims often showing no warning signs beforehand.

What causes the condition?

Dr Sirin noted that a key factor is an imbalance of essential minerals, especially potassium, which affects the heart’s electrical rhythm.

Two major contributing factors include:

• Long-term exposure to certain food toxins, which may accumulate in the body and stress the heart muscle.
• A severe and acute deficiency of vitamin B1 can cause a normally healthy person to feel suddenly fatigued and drowsy, and once they fall asleep, a fatal heart rhythm disturbance may occur almost immediately. This condition is closely linked to malnutrition and poor dietary habits.

The mechanism behind sudden SUNDS can be explained through the heart’s electrical system.

Normally, the heartbeat is regulated by electrical signals generated by minerals that move in and out of heart cells, such as sodium, potassium and calcium, through tiny ‘channels’ that act like gates.

In people with this condition, the sodium channels are fewer or function abnormally due to a congenital cellular-level disorder.

This makes the heart more vulnerable to dangerous rhythm disturbances. Individuals with this underlying condition must take extra care with their diet and overall health to reduce their risk.

The SUNDS is linked to the heart fluttering in these patients, which originates in the ventricles. The ventricles are normally the main pumps that push blood to the body. When there is an electrical short circuit in the ventricular 'gates', it causes the ventricles to beat irregularly.

This leads to excessive, localised electrical activation, and instead of the ventricles pumping strongly to supply blood to the body, they merely quiver or flutter. This prevents enough blood from reaching the body and the brain.

The patient will faint or lose consciousness within 30 seconds. If the condition does not improve, brain death will occur within the next 4 minutes. Ultimately, if not revived, death will ensue within 6 to 7 minutes."

Symptoms and emergency response

When the brain and body do not receive enough blood and oxygen, several warning signs may appear, such as abnormal movements or changes in breathing. Some individuals may briefly lose control of automatic bodily functions due to disrupted nerve signals.

Without effective resuscitation or timely medical intervention to restore a normal heart rhythm, the situation can quickly become life-threatening.

In some cases, the abnormal rhythm may stop on its own, and the person may survive, although prolonged lack of oxygen can still result in lasting neurological impairment.

Treatment and prevention

There are two main medical treatments:

• Medication, depending on the severity.
• Implantable cardioverter-defibrillator (ICD) — a device placed under the skin to correct dangerous heart rhythms. This is often required for high-risk patients and allows them to live normally with regular monitoring.

Patients are advised to avoid contaminated food, ensure adequate nutrition, especially vitamin B, and consume heart-healthy foods such as salmon, tuna, olive oil, legumes and tofu.

Adequate rest, avoiding alcohol and certain substances, and managing overall health are also essential, as episodes are more likely during periods of fatigue or illness.

Most individuals with this condition show no symptoms in their daily lives. However, on certain “high-risk” days, such as when they are sleep-deprived, consume alcohol, use certain substances, take specific medications, or are unwell, the risk of a sudden episode increases significantly. These triggers can cause the condition to occur unexpectedly.

Recommended medical treatment

The most effective long-term treatment is the implantation of a cardiac device that helps stabilise the heart’s rhythm, enabling patients who have previously experienced an episode to live a normal life.

After implantation, patients must avoid pressing on the shoulder or collarbone area where the device is placed, as this may damage the leads.

• Dietary caution is also essential. Patients are advised to:
• avoid foods that may contain toxins or contaminants,
• eat clean, hygienic meals,
• maintain adequate nutrition, especially vitamin B, and
• regularly consume foods that support heart and vascular health, such as salmon, tuna, extra-virgin olive oil, black beans, edamame and tofu.

Emergency response

In an emergency, the recommended first-aid approach is to:

• lay the person flat,
• check for breathing and a pulse, and
• if unresponsive and not breathing, begin chest compressions at a steady rhythm of about 100 per minute until medical help arrives or the person regains consciousness.
• It is important not to perform unnecessary or potentially harmful actions, such as forcing the mouth open with objects.

Dr Sirin notes that individuals with this condition may also have other underlying medical issues, such as neurological or cardiac disorders, which may present with similar symptoms during an episode.