Electrophysiological examinations require the insertion of a catheter into the body and are “invasive”. As such, there are some risks, but they are minimal and the electrophysiology test is relatively safe. In some patients, the catheter insertion site (groin or arm) may bleed and blood may stagnate under the skin, causing local swelling and/or ecchymosis. In rare cases, more serious complications of electrophysiologic testing, including heart or blood vessel injury, thrombosis, and infection, can occur in Ma Jian, Department of Cardiovascular Medicine, Fu Wai Hospital, Beijing. Patient death is much rarer. Although most electrophysiologic exams do not have complications, you should be aware of the potential for these risks. If you would like to know what risks are particularly relevant to you, please consult with your responsible physician.