Heart Arrhythmia Diagnosis

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Diagnosing heart arrhythmias, also known as abnormal rhythms, is critical for treatment. The delicate nature of treating these conditions means you want a highly experienced team.

At Fletcher Allen in Burlington, VT, our electrophysiologists specialize in treating cardiac arrhythmias and are at the forefront of research on the best way to manage these complex conditions. They are typically found only at tertiary or advanced level care centers like Fletcher Allen – the only center of this kind in Vermont.

At Fletcher Allen, our specially trained heart rhythm team includes internationally recognized clinicians who were recruited from the University of Oklahoma's Cardiac Arrhythmia Research Institute, a world-renowned institution on the cutting-edge of developments in heart rhythm disorders.

Heart Arrhythmias: Diagnosis

There are different types of diagnostic tests to determine the type of arrhythmia you might have. They include:

Electrophysiology (EP) Studies

This comprehensive test locates the source of an abnormal heart rhythm. It allows your doctors to determine its cause as well as the best way to treat your arrhythmia. EP studies are performed in our state-of-the-art Electrophysiology Lab and usually take approximately one hour.

What to Expect

Catheters are inserted into the blood vessels and guided to the heart using X-rays. Electrical impulses are then delivered to and received from the heart to assess both normal and abnormal conditions. The test identifies your abnormal heart rhythm by pacing the heart from different locations and at different rates.

Heart Monitoring

To properly diagnose your problem, Fletcher Allen's heart rhythm experts may recommend using a monitoring device to record your heart’s activity over a period of time. This can help identify the cause of the abnormal rhythm. There are many different types of monitoring devices, including:

  • Holter Monitor - This is a small portable electrocardiogram (ECG) machine that records the heart's electrical activity over a 24-48 hour period. It tracks every heartbeat throughout the monitoring period, providing diagnostic information about the type of arrhythmia, how long it lasts, and what might trigger it. The monitor works by attaching small electrodes to the chest. Wires travel from the electrodes to a small portable box that you wear on your belt or shoulder strap. The box continuously records and stores heart rhythm data transmitted by the electrodes. After use, it is returned to your physician who will review the findings.
  • Event Recorder - A device similar to a Holter monitor: it is used to record the heart's activity for a much longer period of time – from 14 to 30 days. You can wear the recorder as you go about your normal activities and press a record button if you feel symptoms. The device is about the size of a pager and can be clipped to a belt or placed in a pocket. Wires connect the device to electrodes worn on the chest. After use, it is returned to your physician who will review the findings. The recorder can be used to determine if recurrent symptoms – such as dizziness, chest pain, palpitation or fainting spells – are caused by an abnormal heart rhythm.
  • Implantable Loop Recorder - These devices are used to help identify the causes of symptoms, which may be related to an abnormal heart rhythm but occur very infrequently. It is a small device implanted under the skin below the collarbone. The recorder continuously records heart activity similar to an ECG for up to two years. If you experience fainting, the device records the heart's activity before, during and after the episode. The information in the device is downloaded at your physician's office for review.

Wireless Monitoring Devices

Wireless monitoring devices are capable of automatically transmitting information from your event recorder or monitor to your physician for review, on an on-going basis. These devices combine monitoring technology, wireless communications and the Internet and often do not require any action on your part.


This non-invasive test uses ultrasound technology to take pictures of your heart. The test assesses the size of the heart's chambers and the quality of the valves, and measures the heart's pumping ability.

High-frequency sound waves travel through a probe called a transducer, which is placed against the chest wall. The transducer picks up echoes of the sound waves as they bounce off the heart. These echoes are transformed into moving images of the heart that appear on a video screen. There are several types of echocardiograms, including:

  • Transthoracic Echocardiogram - The most common type of echocardiogram. Views of the heart are obtained by moving the transducer, or probe, to different locations on your chest or abdominal wall.
  • Transesophageal Echocardiogram - Transesophageal echocardiograms are an alternative type of echocardiogram. A probe that emits high-frequency sound waves is guided through the mouth into the esophagus, to take close-up pictures of the heart. The probe is located closer to the heart without the lungs and bones of the chest wall interfering with the sound waves – this allows for clearer pictures than routine echocardiograms. You will be given medication to make you sleepy and to numb your throat during the test.
  • Signal Averaged Electrocardiogram (SAECG) - Similar to an electrocardiogram, the SAECG is a painless, non-invasive test, with electrodes placed on the skin. These electrodes are attached to the SAECG machine so that the electrical activity of the heart is visualized, and then electronically manipulated by the signal-averaging software for deeper analysis. It provides greater in-depth information by collecting many heartbeats and analyzing them together - a procedure called Signal-Averaging.

Stress Tests

Stress tests are used to evaluate your exercise tolerance and determine if there is a narrowing in an artery leading to the heart muscle - a warning sign of a possible heart attack.

During a stress test, we compare the electrical activity of the heart before, during, and after physical exercise (or after medication to increase heart pumping for patients who cannot exercise). It allows your doctor to determine if there are blockages in the arteries that supply blood to the heart muscle.

What to Expect

  • Your doctor will place approximately 10 electrode patches on the skin of your arms, legs and chest. These electrode patches are hooked up to the electrocardiography or ECG machine, which measures the heart's electrical activity. Your blood pressure is also monitored.
  • Your doctor will first take an ECG reading while you are at rest. Then, you will be asked to exercise on a treadmill or stationary bike. The exercise will begin slowly, and then steadily the speed will change to increase the workload on the heart.
  • ECG measurements are taken continuously. Once you have reached a pre-determined, optimum heart rate, the procedure will end.

Coronary Catheterization

The goal of a catheterization is to determine if there is blockage in the coronary arteries, which reduces the flow of oxygenated blood to the heart.

Cardiologists in Fletcher Allen's Cardiac Catheterization Laboratory inject a dye into the arteries of your heart through a long, thin tube called a catheter. The dye is visible on X-ray videos, helping to identify any blocked or narrowed arteries.

Computed Tomography (CT) Scan

At Fletcher Allen, we offer the latest technology in computed tomography, providing the most accurate images of your heart. A computed tomography or CT scan is a very detailed x-ray that provides information about internal tissues and organs in cross-sections, or thin slices.

A computer takes the cross-section x-rays and uses them to create three-dimensional images. Highly advanced CT scanners provide comprehensive images of organs within seconds with a high degree of accuracy.

Maze Procedure

Usually a Maze procedure is recommended if medications, cardioversion, and catheter ablation have failed to control the Atrial Fibrillation.

The Maze Procedure is an open-heart surgery to create a new, stable, and defined electrical pathway (a surgically created "maze") for impulses to travel within the atria.

The pumping and oxygenation function of the heart is performed by a heart-lung machine during the surgery, and medications are given that briefly paralyze the heart (cardioplegia). This way, the heart is completely at rest while the surgeon performs the procedure.

The surgeon then makes a series, or "Maze" of precise incisions in the heart muscle, interrupting the abnormal electrical conduction paths, while creating a new discrete path for normal, organized electrical transmission of impulses.

Scar tissue develops around the surgical incisions, and helps to maintain the electrical impulses within the proper path. The procedure takes about three hours.

The goal is to control the chaotic heartbeats that result from Atrial Fibrillation; but sometimes medications or a pacemaker may be required after surgery.

T-wave Alternans

T-wave alternans is one of the ways we evaluate the heart's functioning by viewing its electrical activity. It is similar to a standard Electrocardiogram (ECG), but provides greater in-depth information by collecting many heartbeats and analyzing them for specific changes that can occur in diseased heart muscle.

The T-wave Alternans test is a painless, non-invasive test, with electrodes placed on the skin. Electrical activity is recorded while the patient gently exercises, typically either while walking on a treadmill, riding a stationary bicycle, or by simulation of exercise with a medication in patients who cannot exercise.

The objective is to get the patient's heart rate up to approximately 110 beats per minute. A T-wave Alternans computer with software processes the electrical activity of the heart and evaluates beat-to-beat changes that occur at a level too subtle to be seen by the human eye alone. The presence of this alternating pattern identifies patients at a higher risk for having life-threatening arrhythmias in which case the patient would require further evaluation, typically with an EP Study.

A T-wave alternans test is sometimes used to determine:

  • Risk for ventricular arrhythmia following heart surgery or a heart attack
  • Risk for ventricular arrhythmia in patients with weakening of the heart muscle ("cardiomyopathy")
  • The cause of fainting (called syncope)

A T-wave Alternans test is typically done in the Non-Invasive Cardiology Testing Center. A T-wave Alternans test takes about 20 minutes.

Tilt Table

The tilt table is used to determine why you are fainting (fainting is also called syncope).

Fainting or syncope occurs by several different mechanisms. It is important to determine the cause of the syncope to understand the risks and severity of future fainting episodes. A tilt table can provide this information.

The most common type of syncope is vasovagal syncope due to an abnormal neurological reflex. While this cause of fainting can be frightening to those who witness it, it is rarely life threatening. People with simple fainting experience a sudden drop in blood pressure, and/or heart rate often while they are standing or sitting.

During a Tilt Test, the patient lies on a table and is connected to an ECG machine and a blood pressure cuff on one arm. The table is then tilted upwards (head up) to 60 - 70 degrees. The patient will have comfortable straps over their legs and lower chest for a sense of security.

The table is kept up for 15 - 30 minutes with the patient's heart rate constantly monitored and blood pressure checked every minute. If there is no response, the table is lowered to a flat position and a medication may be administered through an IV. The table is then taken back up for another 15 - 30 minutes. If the patient develops symptoms of light-headedness or fainting, the table is laid flat and the test is terminated. The test is performed in the Non-Invasive Cardiology Testing Area.

Learn more about Heart Arrhthmias Treatments.

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