Reminders-from past posts:
HCM cats cannot have steroids, not even creams. Steroids make the body retain fluid; retention for HCM cats leads to CHF. Even in use against other diseases or cancers,the risks of CHF must be weighed. Basically, which disease treatment wins out?
As your HCM cat gets sick, it won't clean itself. Also happens to any cat when sick. Gently clean the coat with baby wipes-alcohol and fragrance free; or cat wipes from pet stores, online stores. Gently brush the cat. Don't rub the fur as it will create snarls. This happened to Cooper near the end (my fault) and he looked horrible as we had to cut out the snarls. Myrna, on the other hand, (and forgive the morbid humor) will be the cleanest dead cat we've had yet-she constantly grooms.
Don't let your sick cat waste away. Feed it as often as necessary to get it to eat (without gaining weight unless it has room to gain.) Use Mirtazapine-appetite stimulant. If a 1/4 tab isn't enough, try a half every 2-3 days. Feed the cat tuna juice, sugar water, KMR kitten formula by hand-9ml every two hours-if the cat's not eating well enough. The body needs energy to run its systems; you want to avoid the body using up the fat stores and leading to hepatic lipidosis (liver disease-which can occur under many circumstances but not eating is a leading cause.)
While a CKD (kidney disease) cat needs to decrease protein and phos levels, a heart disease cat does not. High levels should be avoided but most commercial cat foods have decent levels. As the need for diuretics increase, as the need to get rid of fluid (CHF) is of utmost importance, concentrating on helping the kidneys improve the diuresis process is key. You can do that by using vitamins and supplements to improve kidney support. If the phos levels in the cat's blood work are increasing, then low phos foods will be needed.
Again, an increase in diuretics to fight CHF requires an increase in potassium supplement levels.