Advancements in Pacemakers and Defibrillators

Restoring Regular Heartbeats

Updated technologies allow patients with implanted pacemakers and defibrillators to now undergo full body MRI testing.


A pacemaker is a small device that is most often implanted under the skin near the collarbone to treat patients suffering from slow heart rates. These lifesaving technological tools are comprised of two parts – a generator and electrodes known as “leads” that are placed in one of the heart’s chambers. Pacemakers act as artificial time keepers for the heart when the heart’s natural pacemaker, the sinus node, is defective. When a heart is beating too slowly, pacemakers send low-energy electrical impulses to prompt the heart to beat at a normal rate. 

Pacemakers most commonly treat bradycardia, which is an abnormally slow heart rate. Bradycardia is a serious health problem that can prevent your body from getting enough blood and oxygen.

Implantable Cardioverter Defibrillators

An implantable cardioverter defibrillator (ICD) corrects ventricular tachycardia, a condition that causes an individual’s heart to beat too fast. In this case, the heart is beating so fast that it cannot pump sufficient amounts of blood throughout the body. Ventricular tachycardia can cause cardiac arrest within minutes, and can lead to sudden cardiac death. If a rapid heartbeat is detected, the ICD will deliver an electric shock to normalize the heartbeat.

Similar to pacemakers, these devices also feature electrode leads and are generally implanted just beneath the collarbone. However, they have capabilities that allow for higher energy shocks, and are recommended for individuals at high risk or with a history of cardiac arrest. Many new ICDs also include pacemaker features.

MRI Compatibility

In the past, individuals with pacemakers or ICDs were limited in terms of full body magnetic resonance imaging (MRI) and were often prevented from undergoing chest scans. The reason for this was due in part to the leads associated with the devices. MRI scanners generate alternate magnetic fields. If a lead were to interact with the field, it could generate heat that might burn the heart muscle or shut off the device.

Fortunately, recent advancements have allowed for the creation of MRI-compatible pacemakers and ICDs. Leading manufacturers have released devices that allow individuals to undergo full body scans, even after implantation.

Benefits to Patients

MRIs are often the best option for obtaining the highly detailed imaging of internal organs necessary for planning patient care. Now, patients with the new MRI-compatible pacemakers or ICDs can undergo this important diagnostic imaging without fear of complications.

An Expert Weighs In

“MRI-compatible pacemakers and defibrillators have changed the way patients can receive care. In the past, older devices could be inadvertently reprogrammed or turned off during an MRI. Because of that, patients were limited in receiving test imaging for strokes, joint replacements, back surgeries, and cancer treatments. With advancements in technology, companies are taking it one step further. Their devices can be programmed in advance to recognize the MRI field and protect themselves until the MRI is complete. After the imaging test, they will reprogram themselves back to the patient’s previous settings.”

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