Lasix and Spironolact

I recently had a strong chest pain that didn't want to go away with a couple of nitro sprays, and was hospitalized overnight.  No heart attack was evident from the blood tests, but the blood tests did show a big increase in my BNP enzymes (from 350 to 760), an indicator of increased CHF.  A subsequent stress test indicated no new areas of infarction, but increased damaged areas of the septum and the lower part of the heart, and an EF of 35%.  I go in Monday for an echo, I have a mitral valve issue that may be involved.  Also, I'm experiencing more breathlessness.

My doctor has requested I combine Spironolact along with the Lasix drug I currently take.  However, he made a big deal that I get rid of and never take the Klor-Con that I was taking with Lasix.  I have seen a difference in my SOB when exercising already, but I am struggling to understand.  My Cardiologist explain it, and the pharmacy explained it, but it flew right over my head.  Perhaps someone can explain why too much Potassium is hard on the heart?

[erijon]

My understanding is that even though the serum levels of potassium may be low, there may be high concentrations in the cells. Taking additional potassium will cause  the cell load to be too high causing muscles to not function properly, including the heart.

Take car,

Jon