Heart rhythm problems (arrhythmias) can be diagnosed using a variety of methods. The method depends upon the suspected heart rhythm problem and the physician. An ECG (electrocardiogram) is the most common test. Holter monitors, event monitors, implantable loop recorders, and tilt-table tests may be used when the ECG does not record the arrhythmia. An electrophysiology (EP) study may be done when the arrhythmia is identified as a fast heart rhythm problem (tachyarrhythmia). Other diagnostic tests may check for structural heart disease (heart failure, heart valve disease, coronary artery disease).
Electrocardiogram (ECG )
An electrocardiogram (EKG or ECG) is a test that checks for problems with the electrical activity of your heart. An EKG translates the heart’s electrical activity into line tracings on paper. The spikes and dips in the line tracings are called waves.
Why It Is Done
An electrocardiogram (EKG or ECG) is done to:
Check the heart’s electrical activity.
Find the cause of unexplained chest pain, which could be caused by aheart attack, inflammation of the sac surrounding the heart (pericarditis), or angina.
Find the cause of symptoms of heart disease, such as shortness of breath, dizziness, fainting, or rapid, irregular heartbeats (palpitations).
Find out if the walls of the heart chambers are too thick (hypertrophied).
Check how well medicines are working and whether they are causing side effects that affect the heart.
Check how well mechanical devices that are implanted in the heart, such as pacemakers, are working to control a normal heartbeat.
Check the health of the heart when other diseases or conditions are present, such as high blood pressure, high cholesterol, cigarettesmoking, diabetes, or a family history of early heart disease.
How To Prepare
Many medicines may change the results of this test. Be sure to tell your doctor about all the nonprescription and prescription medicines you take. If you take heart medicines, your doctor will tell you how to take your medicines before you have this test.
Remove all jewelry from your neck, arms, and wrists. Men are usually bare-chested during the test. Women may often wear a bra, T-shirt, or gown. You will be given a cloth or paper covering to use during the test.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results will mean. To help you understand the importance of this test, fill out the medical test information form.
How It Is Done
An electrocardiogram (EKG or ECG) is usually done by a health professional, and the resulting EKG is interpreted by a doctor, such as an internist, family medicine doctor, electrophysiologist, cardiologist,anesthesiologist, or surgeon.
Exercise ECG or Stress Test
A stress test, sometimes called a treadmill test or exercise test, helps a doctor find out how well your heart handles work. As your body works harder during the test, it requires more oxygen, so the heart must pump more blood. The test can show if the blood supply is reduced in the arteries that supply the heart. It also helps doctors know the kind and level of exercise appropriate for a patient.
A person taking the test
is hooked up to equipment to monitor the heart.
walks slowly in place on a treadmill. Then the speed is increased for a faster pace and the treadmill is tilted to produce the effect of going up a small hill.
may be asked to breathe into a tube for a couple of minutes.
can stop the test at any time if needed.
afterwards will sit or lie down to have their heart and blood pressure checked.
Heart rate, breathing, blood pressure, electrocardiogram (ECG or EKG), and how tired you feel are monitored during the test.
Healthy people who take the test are at very little risk. It’s about the same as if they walk fast or jog up a big hill. Medical professionals should be present in case something unusual happens during the test.
A physician may recommend an exercise stress test to:
Diagnose coronary artery disease
Diagnose a possible heart-related cause of symptoms such as chest pain, shortness of breath or lightheadedness
Determine a safe level of exercise
Check the effectiveness of procedures done to improve coronary artery circulation in patients with coronary artery disease
Predict risk of dangerous heart-related conditions such as a heart attack.
Depending on the results of the exercise stress test, the physician may recommend more tests such as a nuclear stress test or cardiac catheterization.
Holter Monitor (24-72 hour ECG)
The Holter Monitor is a device that measures and records heart rhythm over 1-3 days. This test may be done when an ECG does not show the arrhythmia and it still is suspected to be the cause of symptoms. Patches with wires are placed on the chest. The wires are connected to a portable monitor that can be attached to a purse or belt.
During your Holter monitoring, your physician will be looking at a number of factors in order to get an overall picture of how your heart is functioning. Often, abnormalities do not occur during the brief time that a standard electrocardiogram (ECG) is done. A Holter monitor records ECG information over an extended period of time in order to “capture” and then diagnose abnormal heart rhythms that may occur as you go about your daily routine.
Your monitor will help assess recurring symptoms such as dizziness, fainting, and palpitations (rapid heart beat) to determine whether they are caused by an abnormal rhythm. It may also show whether or not certain areas of the heart muscle are receiving adequate blood supply, and will help your physician evaluate the effectiveness of medications or pacemakers that help control heart rhythms.
Event Monitor and MCOT
Event Monitor: A device that monitors heart rhythm and rate for up to one month. During this test, the patient wears a device on the wrist or around the waist. When symptoms are experienced, the patient presses a button on the device to make a recording of the heart activity that just occurred.
Mobile Continuous Outpatient Telemetry (MCOT): A device that measures and records heart rhythm over 10-30 days. This test may be done when an ECG/event recorder does not show the arrhythmia and it still is suspected to be the cause of symptoms. Patches with wires are placed on the chest, the wires are connected to a portable monitor that can be attached to a purse or belt. The monitor is wirelessly attached to a cell phone. When symptoms are experienced, the patient presses a button on the device to make a recording of the heart activity that just occurred. The ECG is transmitted continuously through wireless network to a monitoring center. If a technician at monitoring center observes any significant arrhythmia, he contacts the patient as well as the physician. Since it records continuously it gives the doctor not only the episodes of arrhythmia but also calculates the arrhythmia burden.
Loop Recorder Implant
What is an implantable loop recorder?
The implantable loop recorder (ILR) is a small device which is implanted just under the skin of the chest to the left of your breastbone. The ILR has the ability to record the electrical activity of the heart in two ways. First, it is activated according to heart rate ranges set on the device by your physician. If the heart rate drops below the lowest value set, the ILR will automatically start to record. In the same way, if the heart rate rises over the highest value set, the ILR will also record without the patient’s knowledge. The second way it records is through a “patient activator” whereby you can trigger a recording by pushing a button on the activator. The activator can be used when you experience symptoms such as skipped beats, lightheadedness, or dizziness. To start a recording, simply place the patient activator over the ILR and press the button. A green light will flash when recording is successful. The recording is stored in the ILR itself. Your physician can view both the automatic and triggered events during a routine office visit using a special programmer, which looks similar to a laptop computer.
What Are the Uses?
ILRs are recommended for patients who experience symptoms such as syncope (fainting), seizures, recurrent palpitations, lightheadedness, or dizziness. The ILR is best used in patients who experience these serious symptoms regularly but not often enough to be captured by a 24-hour or 30-day external monitor. Because of the two-year battery life of the ILR, patients will experience extended and constant monitoring, giving the physician ample opportunity to capture any abnormal heart rhythm.
How Is It Placed?
The ILR is placed by your electrophysiologist in a procedure lab under local anesthesia. Conscious sedation can be used but is generally not necessary. It is inserted ubder the skin with a small stab wound. No wires are inserted into the heart. The incision is closed with a suture and steristrips. Patients can go home the same day of the procedure with almost no restrictions on activity or work. The ILR is completely safe under the skin for more than the life of the battery without any adverse effects to the patient’s health or well being.
Tilt Table Test
What is a tilt-table test?
If you often feel faint or lightheaded, your doctor may use a tilt-table test to find out why. During the test, you lie on a table that is slowly tilted upward. The test measures how your blood pressure and heart rate respond to the force of gravity. A nurse or technician keeps track of your blood pressure and your heart rate (pulse) to see how they change during the test.
Doctors use tilt-table tests to find out why people feel faint or lightheaded or actually completely pass out.
Tilt-table tests can be used to see if fainting is due to abnormal control of heart rate or blood pressure. A very slow heart rate (bradycardia) can cause fainting.
During the test, you lie on a special table that can have your head raised so that it is elevated to 60 to 80 degrees above the rest of your body while a nurse or doctor monitors your blood pressure and heart rate. You may have an IV inserted to give medicine or draw blood.
“It was a strange feeling. I felt like I was standing when they tilted the table, but my feet were not touching anything. It was fun – like being suspended in air.” Jim, age 72.
Why do people have tilt-table tests?
Doctors use this test to trigger your symptoms while watching you. They measure your blood pressure and heart rate during the test to find out what’s causing your symptoms. The test is normal if your average blood pressure stays stable as the table tilts upward and your heart rate increases by a normal amount.
If your blood pressure drops and stays low during the test, you may faint or feel lightheaded. This can happen either with an abnormally slow heart rate or with a fast heart rate. That’s because your brain isn’t getting enough blood for the moment. (This is corrected as soon as you are tilted back to the flat position.) Your heart rate may not be adapting as the table tilts upward, or your blood vessels may not be squeezing hard enough to support your blood pressure.
Feeling lightheaded or fainting may be caused by taking certain medicines, severe dehydration, abnormal heart rhythms (arrhythmias), hypoglycemia (low blood sugar), prolonged bed rest and certain nervous system disorders that cause low blood pressure.
Are there risks with tilt-table tests?
There are few risks. People rarely faint during tilt-table tests. And even if they do, it’s safer than fainting on your own in an uncontrolled situation. If a person does faint, usually they feel well again within a minute or so after the table returns to a flat position.
How do I prepare for a tilt-table test?
Don’t eat or drink for at least 4 hours before the test.
If you will have a morning test, your doctor may tell you not to eat or drink after midnight the night before.
If your test is in the afternoon, you can usually eat a light breakfast. Don’t eat lunch.
If you take medicine, ask your doctor if you should keep taking it on your regular schedule before the test.
What happens during a tilt-table test?
A nurse or technician with special training performs the tilt-table test in a hospital or clinic EP (electrophysiology) lab. The test has two parts.
The first part of the test shows how your body responds when you change positions.
You lie on your back on a table. Straps at your waist and knees help you stay in position. An IV (intravenous line) is put in your arm. Small discs with wires are attached to your chest and are connected to an ECG (electrocardiograph) machine to track your heartbeat. A cuff on your arm measures your blood pressure.
The nurse tilts the table so your head is slightly higher (30 degrees) than the rest of your body. The nurse checks your blood pressure and your heart rate.
After about 5 minutes, the nurse tilts the table more. Now you are lying at a 60-degree angle or higher. The nurse continues to check your blood pressure and your heart rate for up to 45 minutes. The nurse will ask you to stay still and quiet during this time, but you should tell the nurse if you feel uncomfortable.
If your blood pressure drops during this time, the nurse will lower the table and stop the test. You won’t need to take the second part of the test. If your blood pressure does not drop after the time is up, the nurse will lower the table and start the second part of the test.
“I guess my blood pressure dropped very quickly, and the nurses told me they could see my ECG change. I didn’t realize it was the end of the test but they said they had gotten all of the information they needed.” Mary, age 78
The second part of the test shows how your body responds to a medicine (isoproterenol) that causes your heart to beat faster and stronger. This medicine is like the hormone adrenaline that your body releases when you are under stress. This medicine may make you feel as if you are exercising. It may make you more sensitive to the tilt-table test if your blood pressure didn’t change during the first part of the test.
The nurse gives you medicine through your IV tube.
Next, the nurse tilts the table upwards to a 60-degree angle.
You may feel your heartbeat increase because of the medicine.
If your blood pressure drops, the nurse will lower the table to the flat position, stop the medicine, and the test will end.
If your blood pressure does not drop after about 15 minutes, the nurse will lower the table and the test will be over.
The tilt-table test can last about 90 minutes if you do both parts of it. If you only do the first part, you may be done in 30 to 40 minutes.
What happens after a tilt-table test?
You may feel tired and a little sick to your stomach right after the test. You may stay in a recovery area for 30 to 60 minutes so nurses can keep track of your blood pressure and heart rate. After recovery, most people can drive home and return to their normal activities. However, if you lose consciousness during the test, you may need to have more observation and testing. Don’t drive home if you have fainted.
Electrophysiology (EP) Study
Several tests are performed in a special lab in the hospital that can take several hours. These tests help pinpoint the location, the type of arrhythmia, and how the arrhythmia responds to treatment. During an EP study, the patient is sedated and small catheters are guided to the heart. The heart’s rhythm is recorded as small amounts of electricity are delivered through the catheter. This internal recording is often compared with an external recording (from electrodes placed on the patient’s chest and back) taken at the same time.
This test (EP Study) will be used by your electrophysiologist to study your heart’s electrical function and locate sites inside your heart that may be causing abnormal heart rhythms. It will be performed in a special lab by your electrophysiologist working with a team of highly-skilled nurses and technicians.
A standard echo is performed by application of an ultrasound probe to the chest wall over your heart (outside the body). By using ultrasound waves, which are not felt and are harmless, a motion picture is made of your heart as it beats in your chest. This motion picture is recorded on videotape and studied by a cardiologist who makes a report for your physician.
A TEE provides clearer and more detailed pictures than a standard echo because the ultrasound probe is moved inside your food pipe (esophagus). Since your esophagus (the passageway from your mouth to your stomach) passes very close to your heart, placing the ultrasound probe down the esophagus gives a much better and more detailed picture of your heart.
A TEE can tell many important things about your heart including its size, how strongly it pumps blood, and how well the valves are working. It is also very useful for identifying many of the common problems that can occur with the heart. It can also visualize heart structures not seen with surface echocardiogram like the left atrial appendage. This makes it a very useful test for providing information about your heart’s overall health, and also presence of any blood clot in the upper chambers of the heart.
Your TEE will be performed by a cardiologist or electrophysiologist who has special expertise in this procedure. Your physician will be assisted by a special ultrasound technician called a sonographer. A nurse will also be present to administer medications, monitor your blood pressure and pulse, and supervise the recovery process.
Your electrophysiologist may decide to facilitate and guide complex ablation with an Intracardiac Echocardiogram. A tiny catheter is inserted into the vein of the leg and advanced to the right upper chamber (right atrium). This Echo probe is then utilized to obtain excellent images of the heart in real time. These pictures provide real time monitoring of the cardiac anatomy, catheter positions and ablation process. These images may be valuable in avoiding complication related to catheter positioning and ablation process. This highly sophisticated tool is most commonly used to enhance the safety and accuracy of complex catheter ablation procedures like ablation of atrial fibrillation.
3D Electroanatomical Mapping
Catheter mapping and ablation are increasingly performed for complex arrhythmias that require a complete understanding of mapping techniques to identify the arrhythmia substrate.
There are several 3D mapping systems available to the physicians today. These systems use an electromagnetic or impedance-based catheter location method that allows creation of a 3D anatomic shell of the cardiac chamber of interest. During mapping, the electrogram obtained at a given site is stored and the activation time catalogued as compared with some selected electric signal preference. The accrued points in the map are assigned to an isochronal color scale based on their respective activation times. In addition to the activation map, maps that display the voltage of the recorded electrograms can be created. For successful interpretation of these maps, a variety of considerations must be understood and meticulously managed. Good catheter contact, correct interpretation of the colors in the map, appropriate choice of reference electrogram, complete mapping of the correct chamber of interest, and strategies to address catheter tip migration with respiration or change in cardiac rhythm and annotation of complex intracardiac signals are all examples of such requisites for success.