Patient: Description of condition (onset, main symptoms, hospital visited, etc.): Female, 45 years old, not in good health, with arrhythmia, poor gastrointestinal condition, this condition: a few days ago, suddenly fainted from exertion, cold hands and feet, purple blood vessels, had a similar condition before; immediately took heart pills, went to the hospital after slowing down and did not find out the cause for the time being; the duration of the onset was short, after slowing down, felt the same as usual; 1. I had a heart test at the local hospital when I fainted, but the doctor said it looked like a blood clot, but did not confirm the diagnosis. Thank you. Hong Jiang, Department of Cardiology, Shanghai First People’s Hospital: The diagnosis is syncope. However, there are many causes of syncope, including cardiac causes (abnormal heart structure, electrical abnormalities, too fast or too slow heartbeat, etc.), brain lesions, cerebrovascular lesions, pulmonary vascular embolism, tearing of the intima of the aorta, electrolyte abnormalities, metabolic abnormalities, mental stress, etc. The most common one is neuroreflex syncope. Therefore, careful examination is necessary. Nevertheless, there are still a considerable number of patients for whom no cause can be found, and close follow-up is required.