Stress cardiac MRI examination

A resting cardiac MRI with contrast agent performed at the same time with adenosine stress MRI also reveals a previous myocardial infarction (scar tissue in the heart muscle) that may help establish a therapeutic plan.

Unlike isotope imaging procedures and coronary CT, MRI does not expose the body to radiation.

The examination is much more reliable than a conventional stress ECG and can be performed on patients who are unable to exercise.

With drug-induced stress cardiac ultrasound in some patients (obesity, lung disease, chest deformity) is not possible to take high-quality (diagnostic) images because the penetration of ultrasound is reduced – MRI can also depict the heart in case of these patients.

It is very safe in case of well-selected patients compared to other drug stress examinations (e.g. dobutamine load) because adenosine has a half-life of only 10 seconds and all possible side effects disappear 1 minute after stopping the drug.

Prior to the examination, our MRI operator will inform you about the course of the examination and ask you about the existence of possible risk factors.

Then you are escorted into the examination room where they prepare you for the examination: the operator places you on the MRI examination table, inserts the cannulas for the administration of adenosine and the contrast agent, places the ECG electrodes on your chest and a cuff for measuring blood pressure on your arm. Chest shaving may be necessary in case of our male patients to apply ECG pads because good quality cardiac MRI recordings cannot be made without a good quality ECG signal.

During the scan, you will be lying on your back, and it is important that you stay still throughout so that the images are sharp. If you have any problems, you can use the emergency call to interrupt the scan at any time.

In the first stage of the examination (15-20 minutes), the heart is recorded at rest, which does not cause any discomfort, you will only hear the click of the MRI machine.

In the second stage, the heart is examined under a drug load. For a short time (5-6 minutes), an infusion pump delivers a small amount of vasodilating adenosine into the body, which has an effect on the heart similar to exercise, temporarily widening the coronary arteries, increasing blood flow to the heart and increasing heart rate. During the stress, your heart rate and blood pressure are closely monitored, and two-way communication with our colleague is provided through the microphone and headphones.

Adenosine is a very safe drug in case of well-selected patients, but with some temporary unpleasant side effects. Most people usually do not feel anything during the first half to a minute of taking adenosine and then experience the following side effects for a few minutes afterwards:

• mild heat wave, flush, sweating
• mild shortness of breath
• chest tightness / sore throat / shoulder pain
• mild headache / dizziness
• fast heartbeat

The side effects listed above may vary from individual to individual, with none or 2-3 occurring at a time.

However, these side effects disappear quickly, within half a minute, when the adenosine is stopped, because the half-life of adenosine is short, only 10 seconds, which means that the drug disappears from the patient’s body.

At the end of the stress examination, a gadolinium-based MRI contrast agent is delivered to your body to see if there are any images of the myocardium that have an area of ​​the heart which blood supply has been reduced due to coronary stenosis. Administration of the contrast agent usually does not result in any unpleasant side effects, after the scan it is excreted through the kidneys and urine. Rarely, it may cause a mild allergic reaction in those who are sensitive to it.

In the last stage of the examination, resting images of the heart muscle are taken for an additional 15-20 minutes.

After finishing the scan, you can return to your normal lifestyle. You may feel tired after the examination, so we recommend that you have someone accompany you.

Adenosine cannot be safely administered in the following cases:

• in case of asthma
• in chronic obstructive pulmonary disease (COPD)
• with regular use of respiratory bronchodilator sprays (e.g. Ventolin, Berodual, etc.)
• in case of recent pneumonia / prolonged bronchitis in the last 3-6 months
• in case of taking medication that has dipyridamole as its active compound
• for certain stimulation disorders (sinus node disease)
• for certain stimulus conduction disturbances (second or third degree AV block)
• if your heart rate is less than 40 beats per minute
• in cases of exceptionally high (> 200Hgmm) or very low blood pressure (<80 Hgmm)
• in case of a recent (within 1-2 weeks) heart attack
• in case of not examined, frequent, recurrent, or resting chest pain

Adenosine will not work properly:

• if you have caffeine in your body
• if you are taking a medicine containing aminophylline

We cannot perform the scan in the following cases:

• Patients with most types of implanted pacemakers or defibrillators (ICD)
• Metal surgical buckles (cerebral aneurysm vascular clips) within the head
• Certain types of inner ear implants
• Metal particles in the eye or skull
• If there are metals implanted in the patient due to previous surgeries, consultation is required prior to the examination

The MRI device uses a very strong magnetic field, which can partly damage the operation of the pacemaker or defibrillator and partly move everything that is metal.

In addition to chest suture wiring, metal implants used to fix bone fractures, artificial joints, coronary stents, and most prosthetic valves, MRI is completely safe, but we check the actual implant before the examination.

To perform the scan safely, we will need a recent ECG to check for any stimulus conduction defects in your heart that prevent you from receiving adenosine.

In addition, a recent (within 1-2 months) kidney function value (GFR) will be required because no gadolinium contrast agent can be given below a certain cut-off value.

Adenosine is a drug that does not work properly when caffeine is in your body. Therefore, do not consume 12 hours prior to the test:

• coffee (no caffeine-free version either)
• tea
• chocolate
• malted beverage (coffee substitute)
• carbonated beverages containing caffeine
• caffeine-containing painkillers as well as cold preparations

As the examination involves the administration of a contrast agent, do not eat for two hours before the test, as nausea / vomiting may occur due to a very rare contrast agent allergy. At the same time, you can drink and take your medications.

Following adenosine stress perfusion cardiac MRI examination, our cardiologist evaluates the images. The finding will not be ready immediately after the test because the analysis of the complex data set takes longer. The result will be available in our online system in 5-10 working days.