Kamma, Kamma Nimitta, or Gati Nimitta

"To the dying man at this critical stage, according to Abhidhamma philosophy, is presented a Kamma, Kamma Nimitta, or Gati Nimitta.

By Kamma is here meant some good or bad act done during his lifetime or immediately before his dying moment. It is a good or bad thought. If the dying person had committed one of the five heinous crimes (Weighty Kamma- Garuka Kamma) such as parricide etc. or developed the Jhānas, he would experience such a Kamma before his death. These are so powerful that they totally eclipse all other actions and appear very vividly before the mind's eye. If he had done no such weighty action, he may take for his object of the dying thought-process a Kamma done immediately before death (Āsanna Kamma); which may be called a "Death Proximate Kamma."

In the absence of a "Death-Proximate Kamma" a habitual good or bad act (Ācinna Kamma) is presented, such as the healing of the sick in the case of a good physician, or the teaching of the Dhamma in the case of a pious Bhikkhu, or stealing in the case of a thief. Failing all these, some casual trivial good or bad act (Random Kamma - Katattā Kamma) becomes the object of the dying thought-process.

Kamma Nimitta or "symbol," means a mental reproduction of any sight, sound, smell, taste, touch or idea which was predominant at the time of some important activity, good or bad, such as a vision of knives or dying animals in the case of a butcher, of patients in the case of a physician, and of the object of worship in the case of a devotee, etc...

By Gati Nimitta, or "symbol of destiny" is meant some symbol of the place of future birth. This frequently presents itself to dying persons and stamps its gladness or gloom upon their features. When these indications of the future birth occur, if they are bad, they can at times be remedied. This is done by influencing the thoughts of the dying man. Such premonitory visions of destiny may be fire, forests, mountainous regions, a mother's womb, celestial mansions, and the like.

Taking for the object a Kamma, or a Kamma symbol, or a symbol of destiny, a thought-process runs its course even if the death be an instantaneous one."
~ Narada Mahathera