Heart MRI: Uses, Risks, Procedure

Medically Reviewed by Dr. K on 20 May 2022

Table of Contents:

  1. Why Do I Need A Heart MRI?
  2. Risks Of A Heart MRI
  3. Preparing For A Heart MRI
  4. What Happens During the Test?
  5. What Happens After the MRI Test?

Heart MRI

To check for heart disease, your doctor can recommend an MRI (magnetic resonance imaging). It creates images of organs and structures within your body using strong magnets and radio waves. During the pumping cycle of your heart, the technique collects information about it and generates images.

Why Do I Need A Heart MRI?


The examination will be used by your doctor to examine the structures in your chest, including your heart, pericardium (heart's outer lining), lungs, and major vessels. An MRI will also aid your doctor in determining whether you have symptoms of conditions such as:


  • Coronary artery disease
  • Pericardial disease
  • Cardiac tumors
  • Heart valve disease
  • Heart muscle disease (cardiomyopathy)
  • Congenital heart disease

Risks Of A Heart MRI

An MRI carries no dangers and has little, if any, side effects. The test does not use ionising radiation, and the radio and magnetic waves it employs have had no known side effects to date. Allergic responses to the dye are extremely rare.


Since an MRI requires magnets, you will not be eligible to get one if you have a pacemaker or some other kind of metal implant from past operations or accidents. Before the procedure, make sure to alert the doctor if you have any implants.


You may feel uneasy in the MRI machine if you are claustrophobic or have discomfort in confined spaces. Remember that there is nothing to be afraid of. Before the examination, discuss your concerns with your doctor. To alleviate your discomfort, they may recommend an anti-anxiety prescription.

Preparing For A Heart MRI


If you're claustrophobic (afraid of enclosed spaces), talk to your doctor about getting a sedative (a relaxing medication) before your MRI. If you take one, you should not consume solid food for 6 hours before taking it to prevent nausea. It's fine to drink “clear" liquids up to 2 hours before taking the sedative, such as apple juice, Jell-O, black coffee, tea, or wine. 


Unless your doctor tells you otherwise, you can take your usual medicines (with sips of water). Since you may feel drowsy after the MRI, make arrangements ahead of time for a friend or family member to drive you home. You should eat and take your daily medication as usual before the MRI if you're not taking a sedative.


As MRIs rely on powerful magnets to produce images, you must remove any metallic or magnetic objects from your person. If you have some metallic implants or metal under your skin, inform the technician. Most metallic implants aren't a concern, such as sternal wires and clips used in heart surgery.


If you have some conditions or implants, your doctor can refuse to let you have an MRI. If you have any of the following, let them know:


  • Implanted pacemaker or defibrillator
  • Older model Starr-Edwards heart valve implant (metallic ball/cage type)
  • Cerebral aneurysm clip (metal clip in a blood vessel in the brain)
  • Pregnancy
  • Implanted insulin pump, narcotic pump, or implanted nerve stimulators (TENS) for back pain
  • Metal in the eye or eye socket
  • Cochlear (ear) implant for hearing problems


Wear a loose-fitting shirt or blouse that you can quickly remove. Wear metal-free pants, such as sweatpants with elastic bands, during the exercise. Belt buckles, metal zippers, snaps, watches, and wallets containing bank or credit cards with magnetic strips should not be worn or carried.

What Happens During the Test?


You'll need to put on a surgical gown first. On your chest and back, the technician will apply thin, adhesive electrode patches. If you're a male, you may need to shave your chest to make them stick. The electrodes are connected to an electrocardiogram (ECG) monitor, which records the electrical activity of your heart during the examination.


A nurse would most likely insert an intravenous (IV) line into a vein in your arm to administer contrast content, a non-iodine-based dye. This increases the visibility of the organs in photographs.


The MRI scanner is a long tube that scans your body when you are lying down on a platform bed. It's ventilated and well-lit, and it's open on both sides. On the scanner bed, you'll lie on your back with your head and legs lifted for warmth. During the test, you can communicate with the MRI operator through an intercom device.


You'll need to lie as still as possible during the test. The technician will ask you to hold your breath for brief periods of time every now and then to avoid blurring of the images caused by your body moving as you breathe.


The equipment can make loud banging noises while scanning. Wearing headphones or earplugs, which you will receive before the test, will help to muffle the sound.


An MRI will take anywhere from 30 to 75 minutes, depending on how much imaging you need.

What Happens After the MRI Test?


The outcomes of the tests will be discussed with you by your doctor.


Your doctor will inform you when you should eat, drink, and resume your normal activities if you took a sedative. You should be driven home by a friend or family member.

If you did not receive a sedative, you may instantly resume your daily activities and diet.


Referenced on 1/5/2021 

  1. Mayo Clinic Staff. (2013). MRI.
  2. What is cardiac MRA? (2012).
  3. What to expect during cardiac MRI. (2012).
  4. Cleveland Clinic.
  5. https://www.webmd.com/heart-disease/diagnosing-mri

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