Heart Failure Support Group
Heart failure is a condition that can result from any structural or functional cardiac disorder that impairs the ability of the heart to fill with or pump a sufficient amount of blood throughout the body. It is often undiagnosed due to a lack of a universally agreed definition and difficulties in diagnosis, particularly when the condition is considered "mild."

B50 vitamins might help a little .
D vitamins 400 IV with calcium 600 mg - would help your entire system - - there are over the counter tablets with both components in them for this.
hope this helps a little.
when you are over tired - you really should get off your feet and put your legs up, eat very lightly, and rest.
Tomorrow, if you still feel over tired - you should seriously consider cutting back on your work session . Personally - i would simply call off , but you might go in and work fewer hours also. Do not know what sort of work you do.
HUgs, Raoul
Going in for a 12 hour work session whan you are over tired is not a good thing to do. You are looking for very serious probelms doing that. PLease consider reducing the session hours or calling off.
hugs