The study is performed in a hospital laboratory by a trained staff that includes cardiologists, technicians, and nurses. The environment is safe and controlled to minimize any danger or risk to the patient. The cardiologist inserts a catheter into a vein through a small incision in the groin after cleansing the are and numbing it with a local anesthetic. This catheter is equipped with an electrode connected to electrocardiographic monitors. The catheter is then carefully threaded into the heart using an x-ray imaging technique called fluoroscopy to guide the insertion. Electrodes are placed in the heart to measure electrical activity along the heart's conduction system and within heart muscle cells themselves. Normal electrical activity is signaled from the heart's natural pacemaker known as the sinoatrial (SA) node. It then travels through the atria (the two chambers on the top of the heart), the atrioventricular (AV) node (connecting the atria to the ventricles), and the ventricles (the lower chambers of the heart). |