Electrophysiology exams are performed in a specially equipped room we call the catheterization room, or electrophysiology exam room.
On the day of the exam, a nurse will wheel you into the catheterization room on a mobile surgical bed and then move you to the X-ray exam bed. There is a large camera above the bed and several TV screens next to it. The catheterization room is also equipped with a heart monitor and other instruments. Ma Jian, Department of Cardiovascular Medicine, Fu Wai Hospital, Beijing
The catheterization room is usually staffed with electrophysiologists, assistants, nurses and technologists.
On the X-ray bed, medical staff will connect various monitoring devices to your body and cover your body with a sterile sheet, and medical staff will also wear sterile gowns and gloves.
Placement of electrode catheters
First, the skin at the catheter insertion site (groin, arm, shoulder or neck) is thoroughly cleaned and disinfected, and a local anesthetic is injected under the skin for local anesthesia.
A small incision is then made in the skin and a vessel (often a vein) is punctured with a puncture needle, through which the electrophysiology catheter is inserted. The electrode catheters used for electrophysiological examinations are long, bendable guidewires that transmit electrical impulse signals into and out of the heart. One or more catheters are inserted into the body and are guided to the heart and eventually placed into the heart through the monitoring of a television screen.
How is an electrophysiological examination performed?
In general, an electrophysiological examination consists of two main components.
Recording of electrical signals: The electrode catheter senses the electrical activity in different parts of the heart and detects the conduction speed of electrical impulses.
Cardiac pacing: The electrode catheter delivers weak electrical stimuli to pace the heart in order to induce certain arrhythmias, allowing the physician to observe these abnormal heart rhythms under artificially controlled conditions.
Once an arrhythmia has been successfully induced, the drug can be administered into the body through an open fluid circuit to test its effect on this arrhythmia. If the arrhythmia cannot be elicited after the drug is administered, the drug is preventing the occurrence of that abnormal heart rhythm.
An electrophysiological examination helps the physician find the exact site of the abnormal electrical activity in the heart, a process known as “labeling”. Determining the location and type of arrhythmia can help your doctor choose the best treatment.
What you may feel during the electrophysiology test
You will be awake during the entire test, but sometimes the doctor will sedate you to ease your nerves, so some patients may fall asleep during the test. However, you can rest assured that you will be monitored by the medical staff throughout the procedure.
Electrophysiological examinations are generally painless, but you may feel some pressure at the insertion site during the catheter insertion process. Also, lying flat for long periods of time may cause you some discomfort. However, you will not feel anything as the catheter travels through your blood vessels.
You will not feel these electrical impulses, but they will induce the arrhythmia that is causing your symptoms, causing you to feel the same symptoms as before, including dizziness, palpitations, chest pain, or shortness of breath, so please inform your doctor as soon as you experience these symptoms.
Arrhythmias that are artificially induced during electrophysiological examinations often stop spontaneously. If the arrhythmia persists, especially if the abnormal rhythm is very fast, it may cause you to faint briefly. When this occurs, the staff will deliver an electric shock to your heart to restore it to a normal rhythm.
Such an arrhythmia can be very dangerous and even life-threatening outside the cath lab. In the cath room, however, trained medical staff will control these arrhythmias with the help of advanced equipment and medications to ensure patient safety.
Electrophysiological examinations can take a long time. For different arrhythmias, the entire procedure may take 2 to 6 hours.
Is electrophysiology safe?
Electrophysiological testing requires the insertion of a catheter into the body and is considered “invasive”. Therefore, there are some risks, but they are minimal, so electrophysiology is relatively safe.
In some patients, the catheter insertion site (groin or arm) may bleed and blood may stagnate under the skin, causing local swelling and/or ecchymosis.
In rare cases, electrophysiologic examinations can have more serious complications, including heart or blood vessel injury, thrombosis, and infection. Patient death is much rarer.
Although most electrophysiologic exams do not have complications, you should be aware of the possibility of these risks. If you would like to know what risks are particularly relevant to you, please consult with your physician.
Catheter Ablation
Cardiac electrophysiology and catheter ablation are two very similar procedures. In fact, your physician may decide to perform both procedures in one visit to the catheterization laboratory. Of course, your doctor will discuss this possibility with you carefully before the test.
Catheter ablation is a non-surgical technique that disrupts the abnormal electrical conduction pathways of the heart that cause rapid heart rhythms.
During cardiac catheter ablation, a special electrode catheter is inserted into the heart, the tip of the electrode is placed next to the abnormal electrical conduction pathway, and radiofrequency energy (heat) is transmitted to the electrode, causing the myocardial tissue containing the abnormal conduction pathway to be heated and destroyed (ablated).
After the electrophysiological examination
After the electrophysiological examination, all catheters are removed and the physician (nurse) will apply firm pressure to the catheter insertion site for 10 to 20 minutes to prevent bleeding. If the insertion site is in the arm, the doctor will often close the incision.
Afterwards, you will be taken back to your room or to the monitoring room. The doctor will decide if you can eat and drink right away, depending on how you are doing after the exam.
Once back in the room, you will have to lie flat for 2 to 4 hours (or even longer), mainly to allow the punctures in the blood vessels to crust over and close. Remember not to curl up or raise the leg on the punctured side during this time. However, you may move your foot or wiggle your toes in order to relieve stiffness in your lower extremity.
The nurse will check your pulse and blood pressure frequently, as well as the puncture site of the catheter. If you suddenly feel pain or bleeding at the puncture site, tell the nurse immediately.
The doctor who performed your exam may discuss some of the results with you shortly after the exam, but a complete and detailed analysis of all test results will take some time to complete.
Depending on the results of the test, you may be discharged home after a few hours of observation or the next day. Please notify your family or friends to pick you up at the time of discharge.
What to do when you return home
Limit your activities for the first 24 hours after you return home. You may walk around, but do not exert yourself or lift heavy objects.
If you notice fresh blood leaking from the dressing at the puncture site, apply firm pressure to the wound with your finger for about 20 minutes. If the bleeding does not stop, call your physician or go to the nearest hospital emergency room for help.
Keep the dressing on the puncture site for about a day. The nurse will tell you how to remove the dressing and when you can start bathing.
Petechiae or small bumps at the skin piercing site are common. They often subside 3 to 4 weeks after the examination.
Call your doctor immediately if you feel pain or heat when you touch the puncture site with your hand, if the petechiae or swelling worsen, or if you have a fever of more than 37.8°C.
Notify your doctor immediately if your tachyarrhythmia recurs or if you feel dizzy, have chest pain or shortness of breath.
l Ask your doctor which medications to stop and which to continue taking.