Cardiac electrophysiology -- can anyone give me more information please?

EP: Cardiac electrophysiology is a branch of cardiology that deals with the electrical activity of the heart. They treat rhythm disturbances and arrhythmias and devices such as pacemakers and defibrillators.

A cardiac speciality: This is speciality that treats and addresses arrhythmias of the heart i.e. 'electrical' disturbances of the heart. This can range to pacemaker and icd therapies to ablation of atrial fibrillation and ventricular tachycardia.

Heart rhythm : Electrophysiology test is exam to test the electrical system of the heart. It is invasive test where catheters are advanced through the veins into the cardiac chambers. Basic measurements are done then heart stimulation is performed to provoke arrhythmia. It is done under controlled setting and your doctor can initiate and terminate the arrhythmia using the catheters