beta blocker for herceptin

This weekend I was doing some research for a friend who had an unusually high lvef of 82%. I found in my research that people with thyroid (in her case, low) can have high and low readings. I also read a response by a cardiologist to a woman whose lvef had gone down to 50% after chemotherapy and was concerned. He was very upbeat about the reading,stating that readings can vary by 4/5 points and that he's seen those with 10% readings that lead good lives. In other words, he was telling her not to worry. If I can find that site again, I will post it for you.