Hi, Thanks for writing in. There are causes other than heart attack and stroke that might cause a sudden passing out. Please find the conditions as follows. 1. Vasovagal syncope. This is a condition when due to the stimulation of the vagal nerve and due to over activity, there can arise a shock like state when the patient becomes suddenly unresponsive. 2. Hypoglycemia. This happens due to subnormal amount of glucose circulating in the blood. This causes insufficient nutrition to the organs including the brain and can cause sudden collapse. 3. A sudden generalized seizure. This happens when there is sudden outburst of electrical activity in the brain and this leads to a severe epileptic seizure from which the patient might take time to make a recovery. 4. Electrolyte imbalances like low sodium or potassium states which give rise to sudden cessation of alertness and awareness. 5. Bleeding from any organ inside the body that is not visible from outside. The patient goes in to a state of hemorrhagic shock. Some bleeding cases can be self contained but the rapid loss of blood causes sudden loss of consciousness. 6. Sudden attacks of apnea due to sleep or even during the day can cause a confusion state and the inability to keep awake due to reduced supply of oxygen to the brain. Please discuss the above possibilities and any reason that might have been pre existent and was not known earlier.