Mom hears her son’s beating heart inside a 4-year-old girl

Here’s your daily dose of bittersweetness.

Heather Clark’s seven-month-old son, Lukas, died in June 2013.

“Losing a child, you lose yourself. I was like, I don’t ever want any mother to go through what I’m about to go through and that’s when I decided to sign the paperwork and save somebody else’s child,” she said.

At Phoenix Children’s Hospital, she met Jordan Drake and her family. Jordan, now 4, has had six surgeries because of a congenital heart defect.

Heather held a stethoscope to Jordan’s chest the other day, and heard her son’s beating heart.

“Knowing that she’s so smart, and so respectful, you know, it just makes it so much easier,” Clark tells CBS News. “Because she’s just exactly what I could picture Lukas being right now.”

Which reminds me: This ad from Argentina is pretty great.

Here’s how to be an organ donor in Minnesota.