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."

zocor - the statin does not have weight gain as a standard side effect.
many drugs do.
if you take grapefruit juice - it can cause the zocor to be much stronger and cause excessive side effects. If so talk to your doctor.
I would have to suggest you contact your doctor - as the use of the zocor may have affected you kidneys and caused the backup - essentially causing some sort of a heart failure issue for you.
Apparantly discontinuing it is helping you.
hugs