An electrophysiology study (EPS) is an intracardiac test that evaluates the function of the heart's electrical signals. This study is administered to check for an abnormal heartbeat (arrhythmia). On some occasions, procedures to correct arrhythmia are undertaken during the EPS.
Reasons for an Electrophysiology Study
An electrophysiology study is performed on a patient who shows signs of heart arrhythmia. A patient may have undergone other cardiac tests, such as an electrocardiogram, before the EPS. In testing the function of the heart's electrical system, a doctor may be attempting to do the following:
- Pinpoint the starting point of an arrhythmia
- Determine risk level for heart events, especially heart attacks
- Check whether a prescribed medication is controlling an arrhythmia
- Evaluate the need for catheter ablation
- Evaluate the need for implantation of a pacemaker or defibrillator
When the EPS shows a need for another procedure, the second procedure is sometimes performed immediately.
The Electrophysiology Study Procedure
An EPS is performed by a cardiologist, in a hospital laboratory. First, the patient's groin or neck area is sterilized and a local anesthetic is applied. Between three and five intravenous (IV) catheters, through which electrodes are threaded into the body, are inserted at the designated site(s). Moving X-ray images are used to guide the catheters into the heart to place the electrodes in the correct locations. The electrodes pick up the electrical signals of the heart, recording them for analysis.
By manipulating the electrodes, the doctor can make the heart skip beats or produce an irregular heart rhythm. Such manipulations help the doctor to determine where an arrhythmia is starting in the heart, and what is causing it. Sometimes medications are administered to produce the abnormal heart rhythm. In either case, producing the arrhythmia assists the doctor in making an accurate diagnosis.
When deemed necessary, treatment procedures, such as the placement of a pacemaker, or catheter ablation, take place in conjunction with the EPS. During the latter, small areas of the heart are targeted and destroyed to eliminate the arrhythmia.
A patients is awake during EPS, which last for an hour or up to several hours. Discomfort from the IVs or catheter, and skipping or racing heartbeats, may be experienced. The patient must be driven home after the procedure.
Electrophysiology Study Results
An EPS helps to diagnose heart rhythms that are too slow, too fast or irregular. The results an EPS may help the cardiologist to pinpoint the cause, including the following, of an arrhythmia:
- Atrial fibrillation
- Atrial flutter
- Heart block
- Sick sinus syndrome
- Supraventricular tachycardia
- Ventricular fibrillation
- Ventricular tachycardia
- Wolff-Parkinson-White syndrome
It is important to detect the location and type of heart irregularity in order to pursue an appropriate course of treatment.
Risks of an Electrophysiology Study
An EPS is safe for most patients but, like all invasive procedures, it carries risks, which include the following:
- Excessive bleeding
- Blood clots leading to embolism or stroke
- Cardiac tamponade
- Heart attack
- Infection at the catheter-insertion site
- Blood-vessel injury
- Perforation of the heart
Such complications are rare, and most EPSs lead to correct diagnosis and effective treatment.