Kim Zolciak is feeling better after being hospitalized for a mini-stroke last month.

While some have speculated that her health scare was due to waist training, the Don't Be Tardy star says her illness was due to a genetic heart condition.

"I was born with a heart defect called the PFO [patent foramen ovale]," Zolciak told ET at her home in Georgia on Wednesday. "They refer to it as a hole in your heart, which is more like a valve that doesn't close. I had a blood clot that was able to cross over to the other side, and that's what caused the mini stroke."

WATCH: Kim Zolciak's Mini-Stroke Revealed She Has a Hole in Her Heart

"The waist trainer has nothing to do with having a stroke,” the 37-year-old mother of six added. “It's ludicrous to even have anybody say that."

In her first interview since the hospitalization, Zolciak told Good Morning America's Michael Strahan that the stroke is what brought her heart condition to light and admitted that she's glad the defect is now on her doctor's radar.

"My doctor said I could have had a heart attack," Zolciak said. "It was inevitable at some point in my life that I probably would have dealt with something like this."

WATCH: Alfonso Ribeiro on Kim Zolciak Getting Kicked Off Dancing With The Stars

Zolciak will need heart surgery soon, but she's expected to return the Dancing With the Stars ballroom floor for the season 21 finale in November. Zolciak and pro partner, Tony Dovolani, were forced to withdraw from the reality competition after she failed to perform in a live show following her mini-stroke. In an Instagram post from earlier this month, she revealed that she hasn't completely hung up her dancing shoes.

"Tony and I have not discussed what we're going to do for finale night," Zolciak told ET. "I requested a song that I was going to dance to last week, had I have been on the show, which has really special meaning now, so I'm hoping that I get that opportunity. We will be rehearsing in November, closer to the finale."