Hello, and welcome to HCM!
The blood pressure you mention is not abnormally low, in fact it is excellent! However, if your mother is feeling faint and dizzy, especially when exercising, this could be caused by a cardiovascular problem, such as aortic stenosis
, sick sinus syndrome
, congestive heart failure
or many others. You mention irregular heartbeat. If this is caused by atrial fibrillation
, her dizziness could be a serious problem. She should be examined by her family physician/internist as soon as possible.
I wish you good health, and thank you for posting on HCM!