Electrophysiologic studies are used to determine the part of the heart that is causing the abnormal rhythm, and which treatments might work best to return that rhythm to normal by evaluating the heart’s electrical conduction system under controlled.
Abnormal heartbeats are not as uncommon as one might believe. Some abnormal heart rhythm only cause annoying symptoms such as palpitations, lightheadedness or dizziness and pose no serious threat to life. Others, however, can pose dangerous risks such as loss of consciousness, seizures, stroke or death.
An electrophysiologic study is a detailed analysis of the electrical conduction system of the heart used to determine whether the heart’s rhythm disturbance is dangerous, and if so, it pinpoints and describes a cardiac arrhythmia in detail to help determine the best treatment.
These varying symptoms can occur whether the heartbeat is seriously slowed, dangerously rapid, or just highly irregular.
Heart rhythm disorders can be part of almost any type of heart disease, can be provoked by various medications or electrolyte (minerals) abnormalities, but can also occur in the absence of readily identifiable underlying heart problems.
Most people know that the heart is the pump the pushes blood through the body to carry nutrients and oxygen where it is needed, but people are not always conscious of the fact that the “pump” depends on an electrical system set the heart rate and stimulate the pump.
The heart is made up of four main cavities–the right and left atriums are the top two chambers of the heart and the right and left ventricles are the bottom chambers of the heart.
In a normal heart, the left and right sides of the heart beat together to maintain a steady supply of blood and oxygen to the rest of the body.
A typical heart beat begins with the sinoatrial node, a cluster of specialized cells located in your right upper chamber, firing an electrical impulse that spreads through the walls of the right and left chambers, causing them to contract, thus forcing blood into the lower chambers.
The impulse then travels to the atrioventricular node, another center of special cells located in the lower part of the right atrium. After a short pause, the pulses travels into the lower chambers, causing them to contract, forcing blood out of the heart to the lungs and body.
Who is a candidate for an Electrophysiologic Study?
When a heart rhythm disturbance is present, a doctor will often recommend an electrophysiologic study. In almost all cases, the electrophysiologic study explains the causes behind the cardiac rhythm disturbance.
Typically, patients who have been selected to undergo an electrophysiologic study have also already been through other exams. The doctor will request an EP study when the following symptoms are present:
- The patient has already survived an episode of sudden cardiac death and an acute myocardial infarct was ruled out.
- Unclear cases of syncope (a brief loss of consciousness) and neurological causes have been ruled out.
- Various types of atrial and ventricular tachycardia.
An electrophysiologic study is used to determine the precise origin of the abnormal heartbeat, how it is triggered, the course of the electrical impulses that might be causing the abnormal beat, and how the course can be changed or terminated.
The study will also establish the connection between the patient’s complaints, such as palpitations, dizziness, loss of consciousness and the abnormal heartbeat, the long term effects of the abnormal heartbeat, and what the most effective treatment might be.
Electrophysiologic studies can determine if a patient needs a pacemaker, determine why a person is fainting if other tests have been inconclusive, determine if a person is prone to troublesome, disabling, or life-threatening fast heart rhythms, and can assess the results of prior therapy for fast heart rhythms.
An electrophysiologic study can determine the precise origin of the abnormal heartbeat, how it is triggered, how the course of the electrical pulses can be changed or how it cab be terminated? The studies can determine the connection between the patient’s complaints (palpitations, dizziness, loss of consciousness) and the rhythm disturbance, how the rhythm disturbance and the risk to the patient can be expected to develop and what the most effective treatment might be.
What can I expect during an electrophysiologic study?
After you are diagnosed as a candidate for an electrophysiologic study, you may be asked to stop taking certain medications several days before your procedure. Blood thinners, heart rate medications and aspirin, for example, can cause difficulty. If you have diabetes, ask the nurse how you should adjust your diabetes medications and/or insulin.
Do not eat or drink anything after midnight the night before the procedure. If you must take medications, drink only small sips of water to help you swallow your pills. When you get to the hospital you will change into a hospital gown for the procedure, which will be performed in the Electrophysiology Lab. You will lie on a bed and the nurse will start an intravenous line to deliver medications and fluids.
You will receive a medication through your IV to make you very drowsy. The medication will NOT put you completely to sleep so if you are uncomfortable or need anything during the procedure you will be able to communicate that to the nurse. During the procedure, you will be asked to report any symptoms, answer questions or follow instructions given by your doctor. However, due to the medications you may not recall the procedure afterwards.
This is completely normal.
Prior to an EP study, blood tests are done to check for any blood component abnormalities or serious bleeding tendencies. A chest x-ray may be taken to detect any unusual anatomic problems. Finally, a baseline electrocardiogram is performed so that the doctor will have something to compare to the results of the electrophysiologic study.
Just before the procedure starts, the nurse will connect you to several monitors that will allow the medical staff to monitor your condition at all times during the procedure. Sterile drapes will be placed to cover you from your neck to your feet.
The staff will clean and shave the area of the incision. The doctor will numb your skin by injecting a local anesthetic in the area, typically in the groin. In some cases puncturing the artery in the elbow may also be necessary to record the activity in the left lower chamber or monitor the blood pressure within the heart. You will feel a slight pinching or burning feeling at first and then the area will become numb.
During the procedure, the doctor will use a fluoroscopy machine (a special x-ray machine that allows the doctor to see your heart and blood vessels), to guide several thin, flexible, electrical catheters (very fine wires each about the thickness of spaghetti) into various parts of the heart.
Once the catheter is in place, the doctor will insert thin wires through the catheters up into the right side of the heart. These wires are attached to an external computer, which is used for monitoring and studying the electrical system of the heart.
The wires allow the electrical currents from the heart to be recorded and displayed on the computer monitor. They also enable the doctor stimulate the heart and artificially induced it to beat in different ways. The doctor will intentionally, under controlled conditions, trigger the heartbeat that had previously caused the patient to suffer from complaints so it can be evaluated.
By doing this, the doctor can determine the type, severity and origin of the disturbance by observing the heart’s reactions to these stimulations.
You should not feel any discomfort during this procedure. Occasionally, palpitations are felt if the heart rate is going fast.
After the physician finishes making measurements of the electrical system, a technique called programmed stimulation is then performed. Programmed stimulation requires pacing the heart at a variety of rates to look for the underlying causes of the abnormal heartbeat.
You may feel your heart beating faster or stronger when the doctor uses the pacemaker device to increase your heart rate. This is normal.
After the test is completed, the wires are removed from the heart and the sheaths are taken out of the groin. The studies usually take 2 hours but can occasionally last longer. You can expect to lie on their back for a longer period.
If no additional procedures are required, the patient usually goes home the same day. In the few days after the study, any physical strain should be avoided.
After the electrophysiologic study
After the ablation is complete, the doctor will remove the catheters and apply pressure to the insertion site to prevent bleeding. You will need to stay in bed from one to six hours to prevent bleeding. You’ll also need to keep your legs still during this time. No stitches are needed. A small sterile bandage will cover the insertion site.
Let your doctor or nurse right away if you notice redness, swelling or drainage at the procedure site.
When you’re feeling more awake, the doctor will discuss the results of the procedure with you and your family. Your doctor will also determine if you need to stay overnight in the hospital. Many patients go home the same day, but some stay overnight in the hospital.
You may feel tired or some discomfort in the chest following a catheter ablation. This is normal. However, please tell your doctor or nurse if any of these symptoms are prolonged or severe.
You will receive specific instructions about how to care for yourself after the procedure including medication guidelines, wound care, activity guidelines and a follow-up schedule. You may need to take an antiarrhythmic medication to control abnormal heartbeats. You will receive the necessary prescriptions and medication instructions from your doctor. Ask your doctor if you can continue taking your previous medications.
About four weeks after the procedure, you should see your doctor for a check up