An electrophysiologist diagnoses and treats a number of conditions including atrial fibrillation, irregular heart rhythm, ventricular fibrillation, a fluttering of the heart muscle etc.
Typical symptoms include fluttering in your chest, racing heartbeat (tachycardia), slow heartbeat (bradycardia), Chest pain or Shortness of breath.
Usually a EP (Elecrophysiologist study) is performed to assess the heart's electrical system or activity and is used to diagnose abnormal heartbeats or arrhythmia.
A electrophysiologist is a healthcare provider who treats heart rhythm problems whereas a cardiologist perform procedures in cath lab like Balloon angioplasty, Coronary and left ventricular digital angiography, Right and left heart catheterization, Rotational artherectomy etc.
It doesn't hurt, but you may feel uncomfortable as your heartbeat is sped up or slowed down.