Pharmacological Cardiac MRI Stress Test: Dobutamine

A pharmacological cardiac MRI stress test is a diagnostic test that creates detailed images of your heart and blood vessels. During the test, a medication (Dobutamine) will be infused through an intravenous (IV) injection. Dobutamine mimics the effects of stress or exercise, increasing the workload of your heart.

The MRI stress test will take at least an hour to perform. When you arrive, you will need to remove your clothing and be given a gown to wear. An IV will be started by a nurse and you will complete an MRI Safety Checklist. A baseline 12 lead electrocardiogram (ECG) and blood pressure (BP) will be obtained prior to the scan. During the test, you must hold still and will be asked to hold your breath intermittently.

The test consists of a resting MRI scan that will take pictures of your heart at rest. A drug (Dobutamine) will be infused through your IV.

Cardiovascular MRI poses almost no risk to the average patient when appropriate safety guidelines are followed. If contrast dye is used, there is a slight risk you may have an allergic reaction to the dye. Tell your doctor if you:

• Have ever had a reaction to contrast dye. Such reactions are usually mild and easily controlled by medication.
• Have kidney failure or other kidney problems. Nephrogenic systemic fibrosis is currently a recognized, but very rare, complication following injection of high doses of gadolinium-based contrast material in patients with poor kidney function.
• Are pregnant, think you may be pregnant or are breastfeeding.

Make a list of any questions and discuss with your doctor before the procedure. Consider bringing a family member or trusted friend to the appointment.

There is no fasting requirement prior to your MRI scan.

If you have a fear of closed spaces, you may ask your doctor to schedule your MRI with sedation to help you relax. If sedation is required, do not eat solid food for six hours prior to the planned sedative. Clear liquids (water, juice, etc.) can be consumed up to two hours prior to the MRI. If a sedative is used, you must make arrangements for someone to take you home afterward.

You will be asked to sign a consent form that gives permission to do the procedure. Read the form carefully and ask questions if something is not clear.

You will complete an MRI Safety Checklist. Tell the technologist if you have ever had a reaction to contrast material. Be sure to report any medical or electronic devices in your body, metallic implants or metal under the skin. Many implants are compatible with MRI scans, but in some cases, it is not advised.

Inform your technologist of the following:

• Implanted pacemaker or defibrillator
• Cerebral aneurysm clip (from previous brain surgery)
• Metal in the eye
• Implanted nerve stimulator, insulin or narcotic pump
• Pregnancy (or you think you may be pregnant)
• Cochlear implant
• Vascular stents

You will remove your clothing, any metal objects (jewelry, bobby pins, eyeglasses, etc.), and given a gown to wear. The technologist will scan you with a metal detector prior to entering the scanner.

The technologist or nurse will place an intravenous (IV) catheter in your hand or arm. If contrast material will be used, it will be injected through the IV during the scan.

Electrocardiogram leads will be placed on your chest to monitor the heart's electrical activity during the scan.

During the MRI, you will be positioned on an examination table. A thin device containing the MRI sensor (coil) will be placed on your chest and held in position with loose fitting straps. The table is then moved into the MRI unit, an open-ended, wide-bore, fully lit and ventilated tube.

You will communicate with the technologist via an intercom (headphones with microphone) and given a hand-held device to initiate communication with staff at any point during the scan. There is also a camera adjacent to the MRI allowing the technologist to see you during the scan.

The technologist will give you breathing instructions. You will hold your breath for short periods of time and be asked to remain perfectly still. The MRI may produce loud banging noises, which are shielded by earplugs and headphones.

A cardiovascular MRI can take 30 to 90 minutes, varying according to the type of scan ordered.

The radiologist will interpret your MRI scan and provide a report to your referring or primary doctor. A follow-up appointment with your doctor may be necessary to review the results of your scan.

If contrast material was used during your MRI scan, you may be watched for a period of time for any reactions. These include itching, swelling, rash or trouble breathing.

Contact your doctor if you notice any pain, redness or swelling at the IV site after returning home. These could be signs of an infection or other type of reaction.

You may resume your usual diet and activities unless your doctor tells you differently.