Do you perceive discomfort when you die of coronary thrombosis?

my mother died of this unexpectedly and no one be around to witness it. i want to know if she felt headache and/or knew what be going on when she died?Do you perceive discomfort when you die of coronary thrombosis?
A heart attack (coronary thrombosis or clot) they say feel like an elephant standing on your chest. With heart ruin (ie enlarged heart or CHF) you get arrhymia and verbs and don't wake up.
Many time personality do not feel any agony just burden in the chest !This lashing ness may be so much they could not make it to words and can not read out anything !More over diabetic person when get heart attack may not get backache as their nerves have diminish ! That is why diabetic people get gangrene in legs as they don't discern pain and near will be loss of perception ! Your mother was lucky that she must not hold felt anguish and she passed away silently !!My brother in decree also passed aways during his sleep ! No one was knowing it !Always YouRsmE