Electrophysiology is a branch of cardiology that deals with electrical activity of the heart. It’s focus in on the diagnosis and treatment of heart rhythm disorders such as atrial fibrillation, bradycardia, and ventricular tachycardia. Electrophysiologists use specialized equipment to measure the electrical activity of the heart and perform procedures such as cardiac ablations as well as implantation of pacemakers and defibrillators.