Dobutamine Stress Echocardiography

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The standard treadmill

The treadmill test is a cardiology examination that allows for the indirect evaluation of blockages in the coronary arteries.

It also assesses cardiovascular fitness.

Easy to perform

The treadmill test is an easy-to-perform examination that provides a lot of information.

It can be considered the “gateway” examination for checking the presence or absence of blockages in the coronary arteries.

Some examinations may be inconclusive

Pour une multitude de raisons, il est possible que l’examen du tapis roulant s’avère insatisfaisant :

  • Effort insuffisant pour accélérer la fréquence cardiaque au niveau requis ;
  • Anomalies électriques de base sur l’électrocardiogramme (ECG), rendant la conclusion impossible ;
  • Irrégularités électriques douteuses, sans conclusion possible ;
  • Etc.

 

For patients with unsatisfactory results or those who cannot perform a treadmill test, an additional examination may be requested by the doctor.

The same applies to an abnormal treadmill test result, which the healthcare professional may want to investigate further.

One of these tests is called Dobutamine Stress Echocardiography.

Its usefulness

This screening test helps determine whether chest pain or other suspicious symptoms are of cardiac origin. It is also useful for monitoring the progress of a patient known to have stable coronary artery disease, meaning they have stable atheromatous plaques in their coronary arteries.

The goal is to clarify the result of a treadmill test that has remained inconclusive.

It can also confirm the result of an abnormal treadmill test by identifying the region of the heart that may have a coronary blockage.

An indirect way to assess coronary artery function

This examination helps determine, indirectly, if there are significant obstructions in the coronary arteries. In other words, it checks if cholesterol plaques are large enough to limit the distribution of oxygen to the heart muscle.

Need an appointment.

An appointment is required for this examination.

Relatively Easy Test

It takes longer to complete than a simple treadmill test because the echocardiography compares the contractility of the heart muscle at rest and immediately after stimulation with intravenous dobutamine.

No particular preparation

There is no need for a specific preparation nor to be fasting. However, it is recommended not to eat too much before this test.

Medication Intake

Beta-blocker pills should be stopped 24 to 48 hours before this test, as they counteract the effect of dobutamine on your heart. Your doctor will give you specific instructions.

These pills are relatively easy to identify in your medication list, as the letters “lol” appear at the end of their names.

For other medications, if no specific instructions have been given, take them as usual.

How the Test Is Conducted

The test consists of two phases: a resting study phase and a stress simulation phase using dobutamine, both conducted during the same session.

On the day of your test, please arrive at your appointment at the designated location.

You must then remove all upper body clothing and wear a hospital gown.

The technologist needs your updated list of medication to complete the information. You must therefore remember to carry your list with you.

You will be asked to lie on a bed for the installation of electrodes. These sensors placed on your skin record the electricity produced by your heart during the examination.

For a more effective electric contact

The keratin on our skin can reduce the electric amplitude of the heart. To prevent this, the skin is lightly scratched with a piece of sandpaper.

Echocardiogram at rest

The test begins with the first echocardiogram. It is the resting Transthoracic echocardiogram.

-Step 1: TRANSTHORACIC ECHOCARDIOGRAM

Cardiac ultrasound, or echocardiogram, is an examination that allows the evaluation of the heart’s anatomy and function using ultrasound.

Just like pregnant women

It is an examination of the same nature as the one used to see the baby in pregnant women. In this case, it is the heart that we will see.

Capturing Images of the Left Ventricle

The technologist or doctor places the cardiac ultrasound probe on the patient’s chest. The ultrasounds pass through the thorax to capture internal images.

The recording focuses on the heart’s function, particularly the left ventricle. Several views from different angles are necessary to obtain a complete picture.

Once the resting images are recorded, the second part of the test begins with the stress simulation.

- Step 2: CARDIAC STIMULATION WITH DOBUTAMINE

Plastic Catheter in a Vein

A catheter is placed in a vein in your arm. This small plastic tube remains in place for the duration of the test and allows for the administration of dobutamine.

Tensiometer on your arm

A device to measure your blood pressure at different moments during the test is installed around your arm.

We are now ready for the “stress” part of the test.

The goal of the test is to accelerate the heart rate

The goal of the test is to have your heartbeat increase to a certain level in order for the exam to be worth it.

The heartrate that must be attained varies with age.

What is Dobutamine?

Dobutamine is a medication administered into a vein to stimulate the heart, thereby increasing heart rate and blood pressure.

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ECG and Blood Pressure Monitoring

Throughout this phase of the test, your blood pressure and heart rate are monitored and recorded, and electrocardiograms (ECGs) are taken.

Start of Dobutamine Infusion

The administration of dobutamine begins. The dose is gradually increased every 3 minutes.

The duration of each period provides the necessary time for your heart to respond to the medication, meaning it will speed up and pump more intensely. Once this “response” is achieved, the dose is increased to the next level until the required heart rate is reached to complete your test.

Don't Worry

During the administration of the medication, you may feel your heart beating harder and faster. Don’t worry, as this is the goal of the test, similar to the physical effort felt when gradually walking up a hill.

-FINAL PART OF THE SECOND STEP OF THE TEST

The Second Transthoracic Echocardiogram

When the target heart rate is reached, an echocardiogram is repeated to compare the images with those obtained at rest.

The technician or doctor may ask you to hold your breath to obtain better images.

Why accelerate the heart rate - what are we looking for?

Coronary artery disease is responsible for blockages in the coronary arteries. These blockages can limit the oxygen supply to the heart muscle.

Physical activity requires increased circulation to the muscles being used. Consequently, the heart must work harder to meet this demand.

But the heart is also a muscle. The increased workload also requires more oxygen.

In the event that one or more blockages prevent sufficient oxygen supply, the heart suffers. This suffering alters the strength of the heart muscle’s contraction in that region. This is why a second echocardiogram is performed at the end of the dobutamine stimulation.

The importance of comparing the images of your heart’s function at rest with those of your heart working under stress cannot be overstated.

Each muscle region of the left ventricle is observed. We look for a region of the heart that contracts less effectively during exercise compared to its normal function at rest. This can indicate that reduced vigor in that region during stress may be associated with a blocked artery.

Once the images are recorded, the dobutamine infusion is stopped.

The Effects Are Short-Lived

The effects of dobutamine disappear within a few minutes.

It is also possible that a medication will be given to you to slow your heart rate back to the level it was at the beginning of the test.

And it’s done

After this second recording, you can change back into your regular clothes and leave.

The results are sent to your doctor

The results are communicated to the doctor who asked for the exam.

You may ask for a copy for another doctor

You may ask for a copy of your results to be sent to another doctor. You simply have to give the name and contact information to the personnel. You may ask at any moment.