The 55-year-old rocker said while he was doing a sound check Friday, his heart rate jumped to 190 beats per minute and stayed that way for more than an hour.
"Paramedics started an IV and gave me a shot to momentarily stop my heart and get it into a normal pattern," he said. "Not knowing if this episode was life-threatening made it even more exhausting."
Stanley said after consulting the paramedics and a cardiologist at Cedar Sinai, he decided not to risk performing that night.
He apologized to KISS fans and thanked his bandmates for going on without him.