During an EP study, small, thin wire electrodes are inserted through a vein in the groin (or neck, in some cases). The wire electrodes are threaded into the heart, using a special type of X-ray, called fluoroscopy. Once in the heart, electrical signals are measured. Electrical signals are sent through the catheter to stimulate the heart tissue to try to initiate the abnormal heart rhythm disturbances for evaluation.There are several ways EP studies which may assist in diagnosing heart rhythm abnormalities. An abnormal rhythm may be deliberately stimulated by a doctor during the EP study so that the underlying problem can be identified. The abnormal heart rhythm may also be stimulated to evaluate the effectiveness of a drug.
During the EP study, doctors may also map the spread of electrical impulses during each beat. This may be done to locate the source of an arrhythmia or abnormal heart beat. If a location is found, an ablation (elimination of the area of heart tissue causing the abnormality) may be done.The results of the study may also help the doctor determine further therapeutic measures, such as inserting a pacemaker or implantable defibrillator, adding or changing medications, performing additional ablation procedures, or providing other treatments. Other related procedures that may be used to assess the heart include resting or exercise electrocardiogram (ECG), Holter monitor, cardiac catheterization, chest X-ray, computed tomography (CT scan) of the chest, echocardiography, magnetic resonance imaging (MRI) of the heart, myocardial perfusion scans, radionuclide angiography, and cardiac CT scans.