Arrhythmia Associates LLP

Our Process - Diagnosis - Invasive Testing

Invasive Testing

Click on any testing process below to learn more:

Cardiac Electrophysiology Study (EPS)

When non-invasive measures do not establish the diagnosis, a cardiac electrophysiology study (EPS) is often helpful. Electrode catheters positioned within the heart at several sites (usually in the right atrium and right ventricle) conveys locally recorded electrical impulses to a computer screen where the doctor analyzes them. The electrode catheters, one millimeter in diameter and about a meter long, enter the veins of the legs at the groin level and the use of up to three or more catheters is routine. These catheters also can convey electrical pulses to the heart to stimulate cardiac electrical activity thereby inducing the patient's arrhythmias. Occasionally, the patient will receive low doses of a drug similar to adrenaline to aid in arrhythmia induction. Analysis of the patterns of electrical activity during arrhythmia establishes the specific arrhythmia diagnosis.

The cardiac electrophysiology study (EPS) is an invasive diagnostic test that helps determine the nature of the arrhythmia experienced by you and helps in deciding whether or not cardiac ablation therapy is appropriate for the arrhythmia encountered. It is separate from the ablation procedure and, in our practice, the two are usually performed at the same setting. The main difference between the EPS and ablation is that while the EP study diagnoses the problem, ablation treats the problem.

Preparation
When discussing the option for ablation with your doctor, you will receive a full explanation of the procedure and its benefits and risks. You will also receive information about alternate therapies (medications) and their efficacy relative to ablation. It is at this time that you will have the opportunity to ask your doctor any questions you may have.

You will probably be brought to the Cardiac Electrophysiology Laboratory (EP lab) on the morning of the procedure. (Morning and early afternoon patients usually go home in the afternoon or evening. Late afternoon ablation patients can expect to stay overnight and go home on the next morning.) Of course, you will not have eaten breakfast before coming to the hospital, and prior to the ablation, a review of all of your medical history, and laboratory studies will have been performed.

On the morning of the ablation you will speak to the anesthesiologist and you will sign consent forms giving written permission to perform the procedure. An IV line will be started in your arm and you will lie down on the lab table beneath the X-ray tube. You will be sedated and on certain occasions, you will be entirely asleep. After shaving and sterilizing the area around the groin and on the upper chest, a large sterile sheet will cover you from neck to toe. Your doctor will inject a local anesthetic into the shaved and cleansed areas, and electrode catheters approximately one millimeter in diameter and a meter long will enter the venous system through needles placed in veins in those areas by your doctor.

Procedure
As many as four catheters will enter the veins and, guided by the fluoroscope, they will be placed within the various areas of the heart. These catheters will record the heart's electrical signals as well as stimulate the heart to beat with tiny electrical currents transmitted through the electrode catheters. In this way your arrhythmia will be stimulated to start and computerized mapping technique will identify the source of the arrhythmia. Occasionally, the arrhythmia you experienced will not be inducible. In this circumstance, your doctors will administer intravenous drugs which are known to help induce arrhythmias. This constitutes the EPS procedure and its results determine if cardiac ablation is appropriate and feasible. For more information on the ablation procedure please see Treatment options, catheter ablation.

Length of Procedure: 1 hour

Recovery
If no arrhythmia is identified, the sheaths and catheters will be removed from the veins and we will have you lie flat for four hours to avoid any bleeding from the catheter sites. We will discuss the results of the EP testing and suggest further recommendations for other testing or treatment.

Implantable Loop Recorder

Sometimes arrhythmias can be very hard to diagnose and despite all available testing the diagnosis is unclear. In this case, we may decide to surgically implant a device called an implantable loop recorder. It is a small device (about the size of a cigarette lighter) that records the heart's ECG. Implanted under the skin of the left chest, it can automatically record and save ECG data if rate alarms are exceeded. A command button worn on the belt can also be pushed to command a recording if symptoms are noted. Later, using a special computerized programming device, the information from the implanted device can be "down-loaded" and analyzed in ECG form. This device is useful to diagnose arrhythmias that occur very infrequently since it can record information for over one year if necessary.