Thank you for posting your query on HCM.
Well looking into your problem I would like to tell you that metoprolol
is a beta blocker
and since you have given a history of irregular hear beat , this drug is used for regularising the heart rhythm also . Your cardiologist must have prescribed it for that .
I cannot comment because it is generally used in hypertension
and then in coronary artery disease generally .So if your treating doctor has prescribed it there must be some indication for that .