Thank you for your query at DoctorSpring.com
I can understand your concern
I afraid there isn't much that a cardiologist can do, in an absence of chest pain or breathlessness pertaining to valve surgery or bypass.
I would advise you to get electrolytes checked and corrected if deranged. Also, his thyroid needs to be checked
A TSH level is also warranted.
Please, feel free to discuss further
Dr Vivek Mahajan