Electrophysiology Lab

  • graphic of pacemakerOur electrophysiology (EP) lab tests for problems within the heart’s electrical system. Your heart beats because an electrical signal inside of it causes the muscle to contract and pump blood. The electrical signal is produced in an area of the heart called the sinus node. This sinus node is the command center of your heart. It determines how fast your heart should beat. The electrical signal travels from the sinus node at the top of the heart, through a central channel down to the bottom of the heart. If your heart rate is too fast or too slow, the EP lab can perform tests to find out why this is happening.

    Cardioversion
    Cardioversion is the process of applying an electrical shock to the heart to make an abnormal heartbeat normal. Before the procedure is done, the patient receives an anesthesia or sedative so that he or she will not feel any pain. Cardioversion can typically be done on an outpatient basis, meaning you do not need to check into the hospital or stay in the hospital after the procedure.

    Automatic Implantable Cardiac Defibrillator Insertion
    An automatic implantable cardiac defibrillator (ICD) is an electronic device that includes a pulse generator and leads. The pulse generator is about the size and shape of a deck of cards and weighs about half a pound. It is implanted into the abdomen just underneath the skin. It is connected to one or more leads that are placed in and near the heart. The lead system sends electrical signals from the heart to the pulse generator, which continuously monitors the heart's rhythm. When the pulse generator receives signals from the lead system that the heart rhythm is abnormal (such as during ventricle tachycardia or ventricular fibrillation), it sends a shock through the lead system to the heart to stop the abnormal rhythm. As long as the heart rhythm remains normal, the ICD monitors the rhythm and waits until a shock is needed.

    People who receive an ICD have generally had a prior heart attack, have a significantly damaged heart, show brief bursts of abnormal rhythm when on a heart monitor, and have successfully undergone electrophysiology testing to rule out other dangerous rhythm abnormalities. Only about 10 percent of all heart attack patients end up needing an ICD.

    The ICD must be implanted surgically. There are a number of different surgical options available to accomplish this.

    Pacemaker Insertion
    When the heart’s electrical system malfunctions, it can result in an abnormally slow heart rate (bradycardia) or an abnormally rapid rhythm (tachycardia). Most pacemakers are designed to correct bradycardias. Left untreated, bradycardias can cause weakness, fatigue, lightheadedness, dizziness, loss of consciousness, or even death. When used properly, pacemakers can correct the problem.

    Pacemakers consist of a generator and leads. The generator is a tiny battery-operated computer roughly the size of a 50-cent piece and about three times as thick. The battery lasts for five to eight years. The lead is a flexible electrical wire. One end is attached to the generator and the other end is passed through a vein into the heart. Generally, one lead is placed in the right atrium and the other in the right ventricle. The pacemaker then helps to regulate the timing of the heartbeat.

    Today’s pacemakers are rate responsive, meaning they determine what the heart rate should be from moment to moment. To determine proper heart rate, the pacemaker may use the following technologies:

    1. An activity sensor in the pacemaker determines body movement. The more the body is moving, the faster the heart rate moves.
    2. A breathing sensor measures the breathing rate. The faster a person breathes, the faster the heart beats.

    Both of these technologies allow pacemakers to mimic the changes in a normal, healthy heart.

    Pacemakers are implanted through minimally invasive surgery. The person receives a local anesthesia in the collarbone area. A small incision is made and the leads are guided through a vein toward the heart. The generator is then placed in the incision site. The entire process generally takes less than 45 minutes.

    After the pacemaker is implanted, a physician must program it. Every so often, it may need to be reprogrammed or changed to suit the individual user. It can be programmed with a handheld device that does not require any surgery.

    Pacemaker/ICD Support Group

    People with pacemakers or ICDs often have questions and concerns, such as:

    • How do I take care of it?
    • How long does it last?
    • Can I use a microwave oven?
    • What does a shock feel like?
    • Will airport security scanners affect it?
    • Can I still do the things I enjoy?

    You can get answers and talk to other pacemaker/ICD users at our quarterly support group meetings. The meetings are open to device users, their family members, and caregivers. There is no charge to attend.

    Cardiac nurse educators lead each session and guest speakers provide information and answer questions. Meetings are held in the Mercer Auditorium located in the Hoskins Center on the Memorial campus. Light refreshments are served at 5:30 p.m. and the meetings begin at 6 p.m. For reservations or more information, please call 912-350-4284.

  • Contact Us
    • The Heart & Vascular Institute at Memorial University Medical Center
      4700 Waters Avenue
      Savannah, GA 31403
      912-350-HAVI (4284)