Heart Attacks and Near Death Experiences

“Eventually the darkness dispersed ever so slowly and a light appeared, like it was a million miles away. It was like a hundred thousand suns- incredibly bright. Words can’t describe the magnitude of the all-consuming love experienced. I felt that I was safely home…” – Ken Mullans, cardiac arrest survivor.

Figure 1: ‘Tunnel Vision’

Near death experiences (NDEs) were first defined in the 1970’s; survivors experienced visions of passing through a dark tunnel, towards a bright light (Figure 1). What is this light? Many believe it has supernatural qualities; survivors return to life a ‘better person’. A 1982 study, of 100+ survivors, challenged the belief that NDE was uncommon. Common features are:

  • Fear, violence or persecution
  • Animals, plants or friends and family
  • A bright light
  • Awareness (accurately recalling events post-cardiac arrest).

NDEs can range from frightening, such as burning alive, to euphoric. Experiencers usually have a positive change of beliefs, attitudes or values; negative outcomes include post-traumatic stress and depression.

 

NDE and Cardiac Arrest

Research implicates NDE is frequent amongst cardiac arrest (CA) survivors; approximately 10–20% report NDEs, including awareness of their resuscitation. Experts believe NDEs are associated with life-threatening illnesses, including CA. Then again, healthy individuals also experience NDEs.

Successful resuscitation is often linked with post-traumatic stress, depression and awareness during anaesthesia. Experts have suggested awareness may also occur during resuscitation. Parnia et al (2014) found 55% of survivors experienced NDEs, but only 2% were aware during resuscitation. Despite being a rarity, research suggests awareness could occur 20-30s after a heart attack (until flat-lining).

 

Figure 2: Right Temporoparietal Junction

Out-of-Body Experiences (OBEs)

These are NDEs with no illusion. For example a patient, ‘floating out of their body’, can recall conversations between doctors, whilst clinically dead. Although theoretically impossible as the brain has shut down, many believe OBEs are evidence of a ‘soul’. Nevertheless a recent study successfully produced artificial OBEs via right temporoparietal junction stimulation (Figure 2).

Verdical perception during CA remains a mystery. It is not an OBE or hallucination; survivors can recall actual events during their heart attack.

 

Explanations

Though only a handful of studies exist, many argue that NDEs are a result of chemicals released whilst the brain is stressed. Various theories implicate endorphins, altered temporal lobe activity, ketamine-like hallucinogens, cerebral hypoxia and serotonin:

  • Cerebral Hypoxia (elevated CO2; low O2): A recent study of CA survivors implicated high CO2; others report zero difference. Moreover during CA there is reduced blood flow to the brain, limiting CO2 supply.
  • Endorphins: Endorphins released in response to stress are suggested to cause reported feelings of peace. Noise produced from dying neural cells are responsible for the increasingly bright light; this tunnel vision is enhanced by fear and hypoxia during death.

 

Explanations are still controversial. Why does NDE not occur in all individuals near death? Experiencers could be pre-disposed by altered temporal lobe activity and sleep patterns; rapid eye movement (REM) sleep has been implicated in NDE-like hallucinations. To conclude NDEs are a response to danger and, despite current research, they remain a mystery.

 

 

References

NDE experiences (including Ken Mullans) at http://celestial.kuriakon00.com/nde/

Figure 1/cover photo: http://litlifecoaching.com/the-light-at-the-end-of-the-tunnel-really-does-exist/

Figure 2: http://en.wikipedia.org/wiki/Temporoparietal_junction

Cant, R., Cooper, S., Chung, C., O’Connor, M. (2012) ‘The divided self: Near death experiences of resuscitated patients – A review of literature’. International Emergency Nursing [online] 20 (2) available from http://www.sciencedirect.com/science/article/pii/S1755599X11000607

Mobbs, D., Watts, C. (2011) ‘There is nothing paranormal about near-death experiences: how neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them’. Trends in Cognitive Sciences 15 (10) [online] available from http://www.sciencedirect.com/science/article/pii/S1364661311001550

Olvera-Lopez, E., Varon, J. (2014) ‘AWAREness during CPR: Be careful with what you say!’. Resuscitation 85 (12) [online] available from http://www.sciencedirect.com/science/article/pii/S0300957214007655

Parnia, S., Spearpoint, K., De Vos, G., Fenwick, P., Goldberg, D., Yang, J., Zhu, J., Baker, K., Killingback, H., McLean, P., Wood, M., Zafari, A., Dickert, N., Beisteiner, R., Sterz, F., Berger, M., Warlow, C., Bullock, S., Lovett, S., McPara, R., Marti-Navarette, S., Cushing, P., Wills, P., Harris, K., Sutton, J., Walmsley, A., Deakin, C., Little, P., Farber, M., Greyson, B., Schoenfeld, E. (2014) ‘AWARE—AWAreness during REsuscitation—A prospective study’. Resuscitation 85 (12) [online] available from http://www.sciencedirect.com/science/article/pii/S0300957214007394

 

 

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Pritpal Kaur Klear

A enthusiastic Biological and Forensic Sciences graduate, with an interest in scientific writing.

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