Industry forecasters project that "Heartbeat Song" could sell around 60,000 downloads in the week ending Jan. 18. ("Catch My Breath," the lead single from her last [non-seasonal] album, 2012's Greatest Hits, sold 87,000 in its first week. It debuted on the Hot 100 at No. 54 and eventually peaked at No. 19.)
The peak is what matters and it's still very early. I'm happy the song isn't free falling on iTunes, though. I feel like with the lack of exposure (no banner or release week promo) it easily could have peaked for a few hours in the top 10 of iTunes and plummeted back towards #100 or something. But it's still top 20. Solid, IMO.