Is Atrial Tachycardia (Paroxysmalatrial tachycardia) a heart disease?

Okay, ever since 2 years ago I have been having sharp pains in my chest. I'd get dizzy at times and have trouble breathing. They have done an EKG, and everything is fine. They have done a Echo (Ultrasound) on my heart, still okay. And the heart monitor showed up that I have a type of SVTs, PAT or known as AT. I have heard that it is a heart disease. I am going to see a Pediatric Cardiologist next Monday from Duke Hopstital in North Carolina. I want to know what is going on with me! Is it a disease or disorder?