It is sure worrisome. He needs an exhaustive workup by a cardiologist, to make sure that a structural/arrhythmic cause is not the reason why he lost consciousness. This may include an MRI
, and if nothing is found with an abnormal EKG even an electrophysiology study could be considered. If you rule these malignant causes, then it becomes a less serious issue probably in terms of prognosis and events.
Dr Brenes-Salazar MD
Mayo Clinic MN