herceptin and heart function

Hi there my heroes,
I have a question--my mother has been on herceptin for 3 years for liver mets. She has had a miraculous response. NED throughout her body (except for brain mets, which are under control, but which herceptin has no apparent effect on anyway). Her heart function a year and a half ago was 75%. Now it is 50%. Her onc doesn't seem concerned. What does this mean? Does anyone have any info? I'm worried if she has to stop the herceptin.
Any input is greatly appreciated.
Thank you!

This was taken from the web site below. Read the article to understand more. Generally, your mom is on the lower end of the scale, but nothing to be majorly concerned about at this point. I am sure her onc will continue to monitor her heart. At some point he/she may decide to give her a "vacation" so that her heart can get strong again.

>In general, most incredibly fit people are often in the 70s while "regular" people are in the high 50s and in the 60s. It is very rare for oncologists to give additional chemotherapy containing anthracylines (the chemotherapeutic agents mentioned above) or Herceptin if the LVEF goes much below 50, except in unusual situations. <

http://www.yana.org/herceptininteractions.htm

[Lolly]

Hi Lee; I've always tested in the mid 50's since starting Herceptin, and my onc has always said he would only start to worry if it dropped below 50. As Maryanne points out, some who've had to take a vacation from Herceptin when their heart function dropped too low were then able to start up as their heart improved after a rest...
That said, I've been told that if the heart is going to show damage from Herceptin it will usually happen sooner rather than later, and if your mom is stable at 50 after 3 years it would be unusual for things to suddenly change at this late date, unless a new drug is introduced that would precipitate a change for the worse, and her docs will no doubt be watching for that.

<3,
Lolly

Thank you two so much. I guess I just get worried because it was 75% and now it is 50%. Can other things affect it? Just lack of exercise or battling the brain mets? I saw that many of you take Q10. Is around 300 mg the "going" dose? Thank you so much!