Hi, I understand your concern and I ll try to help you. The sudden loss of frame of consciousness that you reported is compatible with syncope. There are several causes of syncope is the most common type is the vasovagal syncope, but there are also syncopations of origin for cardiac arrhythmias and neurological diseases. The picture of your brother has several characteristics of vasovagal syncope, but the information you reported is insufficient to confirm the diagnosis. This type of syncope is often triggered by stress such as fear of needles, fear of heights, long periods of standing and in the same position, hot and stuffy places. Usually there is complete loss of consciousness, which can last a few seconds and the patient wakes up slowly, often with nausea and dizziness, and skin pallor and general ma-being. After a few minutes the person is totally normal. This all occurs by stimulation of the autonomic nervous system that causes bradycardia (reduction in frequency of heartbeat and drop in blood pressure). To confirm this diagnosis and away from others is necessary look for a good Cardiologist to make a detailed medical history and discard cardiac and neurological causes. So I use some additional tests beyond echocardiography, holter as 24 hours, exercise testing, in some cases the tilt test and if there are signs of neurological causes, request a cranial tomography and evaluation neurologist. Hope I have answered your question. If you have any further questions I will be happy to help you. Wish you good health.