What is an electrophysiological study?
An electrophysiological study (EP study) is a test used to evaluate your heart's electrical system and to evaluate for abnormal heart rhythms.
Natural electrical impulses coordinate contractions of the different parts of the heart. This helps keep blood flowing the way it should. This movement of the heart creates the heartbeat, or heart rhythm.
During an EP study, your doctor inserts small, thin wire electrodes into a vein in the groin (or neck, in some cases). He or she will then thread the wire electrodes through the vein and into the heart, using a special type of X-ray “movie,” called fluoroscopy. Once in the heart, the electrodes measures the heart’s electrical signals. Electrical signals are also sent through the electrodes to stimulate the heart tissue to try to cause the abnormal heart rhythm so that it can be evaluated and its cause can be found, or to help evaluate how well a drug is working.
During the EP study, specialists in heart rhythms or an electrophysiology specialist doctors may also map the spread of the heart’s electrical impulses during each beat. This may be done to help locate the source of an abnormal heartbeat.
What are the risks of an electrophysiological study?
Possible risks of an electrophysiological study (EP study) include:
- Severe rhythm problems
- Bleeding and bruising at the site where the catheter(s) is put into a vein
- Damage to the vessel that the catheter is put into
- Formation of blood clots at the end of the catheter(s) that break off and travel into a blood vessel
- Rarely, infection of the catheter site(s)
- Rarely, perforation (a hole) of the heart
You may want to ask your healthcare provider about the amount of radiation used during fluoroscopy and the risks related to your situation. It is a good idea to keep a record of your radiation exposure, such as previous scans and other types of X-rays, so that you can inform your healthcare providers. Risks associated with radiation exposure may be related to the cumulative number of X-rays and treatments over time.
For some people, having to lie still on the procedure table for the length of the study may be uncomfortable or painful.
There may be other risks depending on your specific medical condition. Be sure to discuss any concerns with your healthcare provider before the test.
What happens during an electrophysiological study?
You may have an electrophysiological study (EP study) on an outpatient basis or as part of your stay in a hospital. Testing may vary depending on your condition and your healthcare provider’s practices.
Generally, an EP study follows this process:
- You will be asked to remove any jewelry or other objects that may interfere with the test.
- You will remove your clothing and put on a hospital gown.
- You will be asked to empty your bladder before the test.
- If there is a lot hair at the area of the catheter insertion (often the groin area), the hair may be shaved off. This will help in healing and reduce the chance of infection after the test.
- An intravenous (IV) line will be started in your hand or arm before the test. This is so that medicine and IV fluids can be given, if needed.
- A member of the medical team will connect you to an electrocardiogram (ECG) monitor to record the electrical activity of your heart and monitor your heart during the test using small electrodes that stick to your skin. The team will also monitor your vital signs (heart rate, blood pressure, breathing rate, and oxygen level).
- There may be several monitor screens, showing your vital signs and the images of the catheter being moved through your body into your heart.
- You will be given a sedative in your IV before the test to help you relax. However, you will likely stay somewhat awake during the test.
- Your doctor may check and mark your pulses below the IV site to check the circulation to the limb below during and after the test.
- A member of the medical team will inject a local anesthetic into the skin at the site where the catheter and wires are to be put into the vein. You may feel some stinging at the site for a few seconds after the local anesthetic is injected.
- Once the local anesthetic has taken effect, your doctor will insert a sheath, or introducer, into the blood vessel. This is a plastic tube through which the catheter(s) will be put into the blood vessel and advanced into the heart. Catheters are long hollow tubes that provide a path through the blood vessels to protect the surrounding blood vessel from trauma of the equipment passing through the vessel.
- One or more catheters will be put into the sheath and into the blood vessel. The doctor will thread the catheters through the blood vessel into the right side of the heart. Fluoroscopy (a special type of X-ray that is displayed on a TV monitor), is used to help advance the catheters to the heart. Your doctor may let you watch this process on the screen.
- Once the catheter(s) is in the right place, your doctor will send very small electrical impulses to certain areas within the heart. You may feel your heart beat stronger and faster. If a heart rhythm abnormality is started, you may feel lightheaded or dizzy. Medicine may be given or a shock may be delivered to stop the arrhythmia. You may be sedated before a shock is given.
- If a certain area of tissue is found to be causing a rhythm problem, the doctor may do an ablation to destroy the abnormal tissue. This is done with heat (radio waves, called radiofrequency ablation) or cooling (called cryothermy or cryoablation).
- Sometimes adrenaline type medicines are given to help induce arrhythmia. You may feel your heart beating more rapidly and forcefully. You may feel some anxiety.
- If you notice any discomfort or pain, such as chest pain, neck or jaw pain, back pain, arm pain, shortness of breath, or breathing difficulty, let the doctor know right away.
- Once the EP study is done, the catheter(s) will be removed. Pressure will be put on the insertion site so that a clot will form. Once the bleeding has stopped, a very tight bandage will be placed on the site. A small sandbag or other type of weight may be placed on top of the bandage for extra pressure on the site, especially if the groin was used.
- The staff will help you slide from the table onto a stretcher so that you can be taken to the recovery area. If the catheter was put in the groin, you will not be allowed to bend your leg for several hours. To help you remember to keep your leg straight, the knee of the affected leg may be covered with a sheet and the ends will be tucked under the mattress on both sides of the bed to form a type of loose restraint.
- An electrophysiological study (EP study) may be done on an outpatient basis or as part of your stay in a hospital. Testing may vary depending on your condition and your doctor’s practices.
The results of the study may also help your healthcare providers decide whether more treatment is needed and which treatment would be best. You may need a pacemaker or implantable defibrillator, receive or change medicines, undergo an ablation procedure, or receive other treatments.
What happens after an electrophysiological study?
In the hospital
After the test, you may be taken to the recovery room for observation or returned to your hospital room. You will stay flat in bed for several hours after the test. A nurse will monitor your vital signs, the insertion site, and circulation or sensation in the affected leg or arm.
Let your nurse know right away if you feel any chest pain or tightness, or any other pain, as well as any feelings of warmth, bleeding, or pain at the insertion site.
Bed rest may vary from 2 to 6 hours depending on your specific condition.
In some cases, the sheath or introducer may be left in the insertion site. If so, you will be on bed rest until the sheath is removed. After the sheath is removed, you may be given a light meal.
After the specified period of bed rest, you may get out of bed. The nurse will help you the first time you get up, and may check your blood pressure while you are lying in bed, sitting, and standing. You should move slowly when getting up from the bed to avoid any dizziness from the long period of bed rest.
You may be given pain medicine for pain or discomfort related to the insertion site or having to lie flat and still for a prolonged period.
You may go back to your usual diet after the test, unless your healthcare provider tells you otherwise.
When you have recovered, you may be discharged to your home unless your doctor decides otherwise. If this test was done on an outpatient basis, you must have another person drive you home.
Once at home, check the insertion site for bleeding, unusual pain, swelling, and abnormal discoloration or temperature change. A small bruise is normal. If you notice a constant or large amount of blood at the site that can’t be contained with a small dressing and stopped by putting pressure over the area, contact your doctor right away.
It will be important to keep the insertion site clean and dry. Your doctor will give you specific bathing instructions.
You may be advised not to participate in any strenuous activities for a few days after the test. Your doctor will tell you when you can return to work and go back to your normal activities.
Contact your healthcare provider if you have any of the following:
- Fever with a temperature higher than 100.4°F (38.0°C) or chills
- Increased pain, redness, swelling, or bleeding or other drainage where the catheter was inserted
- Coolness, numbness or tingling, or other changes in the affected leg
- Chest pain or pressure, nausea or vomiting, profuse sweating, dizziness, or fainting
Your healthcare provider may give you other instructions after the test, depending on your situation.