XXXXXXXX - you should check the archives of the FHL on "cardiomyopathy" - and you can also check out Ferret Central and Mike Janke's site at http://www.miamiferret.org for information on heart disease. In response to your question, Lasix is a diuretic, which expels excess water in the body by filtering it through the kidneys. However, there are additional medications that are useful in treating heart disease, such as digitalis (which strengthens the contractions of the heart) and enalapril, which works as a vasodilator, helping to relieve some of the stress on the heart. It is difficult to say which are the most appropriate in this case, but all should be considered, and in most cases of heart disease, will all eventually be required to stop the progression of this disease. Remember, heart disease is never cured - all that we can do is stop, or slow it's progression. With kindest regards, Bruce Williams, DVM [Posted in FML issue 3411]