Hello! Welcome and thank you for asking on HCM! I understand your concern and would explain that his symptoms don t seem to be related to any cardiac disorder. Does he have any head spinning? What were his blood pressure values during this episode? This symptomatology could be explained by an inner ear disorder, such as benign paroxysmal positional vertigo or labyrinthine inflammation. Another disorder which could mimic this clinical scenario would be a vertebro basilar TIA (transient ischemic attack). His past medical history for stroke, raises the suspicions of a TIA in the posterior circulation of the brain. I recommend consulting with the GP for a careful physical examination, a resting ECG and some blood lab tests (complete blood count, inflammation tests, kidney and liver function tests, fasting glucose, blood electrolytes,etc). An ENT consult coupled with the labyrinthine tests is needed to rule in/out a possible inner ear disorder. A Doppler ultrasound of the neck vessels is necessary to examine the blood flow in these vessels and the blood supply to the brain and exclude a possible vessel stenosis in this level. Hope to have been helpful! Best regards, Dr. Iliri