A 65-year-old man suddenly loses consciousness. Witnesses report he became pale and fell to the ground, regaining consciousness within 30 seconds, no confusion or cionvulsions. He reports feeling lightheaded and nauseated before the episode. His physical exam and ECG are normal. What is the most likely cause of his syncope?
A. Vasovagal syncope
B. Cardiac arrhythmia
C. Orthostatic hypotension
D. Seizure
E. Hypoglycemia