“I was born with a decent size hole in my heart and my parents were told that it would eventually go away with time. It didn’t, and progressed into irregular beating and cardiac arrhythmia. Finally, when I was 18, my doctor noticed that the sound of my heart had changed and that she didn’t think it was functioning the way it should be. I went to a specialist and he determined that the AV node was blocked and that my heart was only beating half of what it should be. I got a pacemaker on December 23, 2003 when I was just 18. A couple years later, as a Christmas gift, my fiance paid for me to get the medical symbol for the pacemaker tattooed on my upper right wrist.”

Originally published June 11, 2008. Copyright 2008 Carl Zimmer.