New defibrillators open doors to diagnostic tools

Patients who require a defibrillator to regulate abnormal heart rhythms can now have an MRI thanks to technology and a team at the Foothills Medical Centre.

Traditional defibrillators are implanted under the skin to correct irregular heart rhythms but they can malfunction in an MRI so patients with the devices are unable to use the scanner to diagnose conditions like back and joint problems, strokes, and certain cancers.

“Every year, about 800 Albertans require an implantable defibrillator due to electrical problems in their heart,” says Dr. Vikas Kuriachan, an Alberta Health Services (AHS) cardiac elecrophysiologist. “One of the issues has been that, when you put these kind of systems in, you can’t ever get an MRI scan done, because the magnetic field will interfere with the device.”

Kuriachan says the MRI can also affect the defibrillator’s hardware components and materials and says 50 to 70 percent of patients with the traditional device should have had an MRI for other ailments but were unable to.

In August, doctors inserted a new MRI-compatible implantable cardioverter-defibrillator or MRI-ICD into 69-year-old Brian McComb.

“This new device will allow patients with defibrillators to have MRI scans and improve the level of care we can offer them,” said Dr. Kuriachan.

McComb, who was suffering from congestive heart failure, became the second patient in Canada, and the first in the West, to receive the device.

“After the procedure, I was up and walking within 24 hours. Now I want to focus on spending time with my grandkids,” said McComb. “If my heart stops, it gives me a lot of peace of mind to know I have the MRI-ICD in my chest.”

Calgary is one of two Canadian cities that will take part in a two-year international study using the new MRI-ICD and will implant the device on patients who:

  • Have a high probability of needing an MRI
  • Are young or middle-aged
  • Have spine, joint or neurological problems
  • Have a history of cancer or other problems that may require an MRI for diagnosis

“If you come in with another heart problem and there are other characteristics we look for and we say hey look, this person is at high-risk for having a sudden death, then those are the patients that we would put these kind of defibrillators into,” said Dr. Kuriachan.

The Director of Libin Cardiovascular Institute of Alberta and Department Head of Cardiac Sciences says he thinks all implantable defibrillators will be MRI compatible in the future.

“This will be a tremendous step forward in the level of care we are able to provide patients who require defibrillators,” said Dr. Todd Anderson, “Libin, its physicians and researchers are known for pioneering new and innovative technologies, and this is just one more example of that work.”

Some of the study patients will be randomly selected to have a routine MRI scan and will have their implants checked to make sure the devices continue to operate as they should.