Cardinals defensive end J.J. Watt back on the field just days after he says his "heart was shocked back into rhythm"

Arizona Cardinals defensive end J.J. Watt took the field Sunday after tweeting that he would be playing despite having "had my heart shocked back into rhythm" after going into atrial fibrillation last week. 

Watt's tweet was posted just a few hours before the Arizona Cardinals were set to play against the Carolina Panthers.

"I was just told somebody leaked some personal information about me and it's going to be reported on today," Watts tweeted on Sunday. "I went into A-Fib on Wednesday, had my heart shocked back into rhythm on Thursday and I'm playing today. That's it."

Watt was recently listed as questionable for Sunday's game for a calf injury, according to an NFL injury report published on Wednesday, the day he said he went into atrial fibrillation.

According to the Mayo Clinic, atrial fibrillation is "an irregular and often very rapid heart rhythm that can lead to blood clots in the heart." Atrial fibrillation increases the chances of having a stroke, heart failure and other heart-related complications, the Mayo Clinic said.