*steps in reluctantly* Congestive heart failure is terminal. The second test, probably to draw fluid from the lungs, would have tested for an aggressive infection accelerating the cardiomyopathy. Any medications, regardless of source, will merely delay heart failure. The lasix is a diuretic meant to help reduce fluid build-up around her heart, which further restricts her ability to breath and puts strain on the heart... weakening it further. I believe the second medication is for the arrhythmia that typically occurs with cardiomyopathy.

I realize this isn't what you want to hear. Your cat's going to die but with medication and timely intervention, heart failure will be delayed. Whenever you notice she goes into accelerated heart failure, hie to the vet. It will be far less painful for her than gradual asphyxiation.