Hello! Welcome and thank you for asking on HCM! I understand your concern and would explain that your symptoms seem to be related to a low blood pressure or orthostatic hypotension. Have you measured your blood pressure during these episodes? I recommend to closely monitor your blood pressure in sitting and standing position. A decrease in your blood pressure more than 20mm Hg when standing up, compared to sitting position would be indicative of orthostatic hypotension. A head up tilt test would be necessary to rule in/out this disorder. But I would also recommend consulting with your GP for a careful physical examination, a resting ECG and some blood lab tests : - complete blood count (for chronic anemia) - kidney and liver function tests - thyroid hormone levels - cortisol plasma levels (adrenal gland function) - fasting glucose (for possible hypoglycemia) - blood electrolytes, etc. to exclude other possible metabolic causes related to this symptomatology. Hope to have been helpful! Best regards, Dr. Iliri