19 year old with palpitations....is it just anxiety?

This 19 year old male presented to the ER feeling like his heart was going to "come out of his chest." He has mild chest pain, mild dyspnea. Denies drug use. VS: 114/90, RR 14, 97.8, 99%. He denies any medical history or medications. This is a tough case, because at first glance this could look regular. And if its not, what is a 19 year old doing with Atrial fibrillation, an "old persons" disease?

His UTOX was negative. His labs including a TSH were all normal. His CXR was normal as well.

His second ECG reveals a clue. He has a delta wave, which is significant for WPW. It is common for young people with WPW to have AF with RVR, and nodal blockers are absolutely not to be used as it will force the electrical impulse down the abberant pathway making the tachycardia worse. His second ECG was done after he was given IV procainamide. He underwent urgent ablation and is doing well.