Electrophysiologic study of the heart is a test of the electrical conduction system of the heart (the system that generates the heart beat). EKG results may indicate that a patient is at high risk for an irregular heartbeat and need EPS to further study the heart rhythm. During EPS, the electrical activity of your heart is checked by recording it from the inside. During the test, the
doctor looks for reasons why a patient may be having certain symptoms such as an irregular heartbeat.
Prior to an EP study, blood tests are done to check for any blood component abnormalities or serious bleeding tendencies. A chest x-ray is obtained to detect any unusual anatomic problems, and a baseline ECG is performed. All eating, drinking and smoking must cease at least 6-8 hours pre-test. Detailed information about the test, including the reason(s) the test is being performed, procedural technique, and potential serious test-related complications are provided to the patient (and/or family members) before a consent form is signed.
The test requires that the patient eat nothing after midnight the night before. Some medications may need to be withheld before the test. These include some medicines that regulate the heart beat, the powerful blood thinner coumadin as well as some diabetic medicines. Outpatients can have the test done in the morning and go home later that day. Someone else should drive them home. They should rest for the remainder of the day. They can resume their normal activities the following day unless advised otherwise by their physician.
The test is performed by placing thin plastic tubes into a vein where the leg connects to the stomach. A local anesthetic is given as well as a mild sedative. The procedure is not painful and the patient is not put to sleep. After being placed into the vein, these long thin tubes, called catheters, are then passed into the heart under fluoroscopic guidance. These catheters measure the electrical signals generated by the heart. This gives a much more detailed analysis of these signals than does a simple ECG. The catheters are also used to rapidly pace the heart, i.e. make the heart beat fast. The electrical conduction system of the heart is also measured during this rapid pacing and the heart is observed during this rapid pacing to see if any abnormal heart rhythms develop.
Whenever catheters are inserted into the blood stream and heart, there is a small risk of developing potential complications which may include bleeding, infection, blood vessel damage or induction of potentially life-threatening heart rhythm disturbances. The EP laboratory is staffed by skilled personnel and equipped with devices and medications needed in the event any of these complications occur. Deaths attributable to an EP study are very rare.
Upon completion of the study, all catheters are removed, pressure is applied to the insertion sites for 10 to 30 minutes to seal the punctures, and the patient is then monitored several hours. Discussions of the EP test findings and any further treatment recommendations are held later between the patient, his/her family physician, and the electrophysiologist.