Dear Dr. Mahler:

My doctor told me that I have “severe” COPD, and I have been stable for years until one month ago when I had sudden breathing difficulty and I became lightheaded. The diagnosis was “afib,” and I am now taking a blood thinner medication to prevent clots from forming in my heart.

I am having a problem finding out about this heart condition. Thanks very much for your help.

Al from Grove City, PA