Welcome to HCM!
I have read your question and from that there are few important points-from few weeks your husband has lightheadedness
in hands and feet, EKG has reduced pulse rate.
From all this one thing is almost ceratin that it is not just dehydration
, as it would improve at least for some time with fluids.
Had I been at your palce I would definittely take him to a cardiologist for consultation.
You have not told anything more about his EKG reading which must be having some essential information (about the cause and type of heart problem)or his blood pressure reading.
However, from the symptoms I feel that he may require an ECHO, along with some blood tests.
Till you see a doctor I want that he should avoid any sternous exercise (it wont harm him in any way to take rest).
I wish him good health and hope answer helps you in dealing with this.
Feel free to ask more questions.
Dr. Manisha Gopal.