Up to this point MRI procedures had been contraindicated for patients with implanted pacemakers due to the potential for serious complications. Each year, an estimated 200,000 pacemaker patients in the United States have to forgo MRI scans, which are critical for making a wide range of health diagnoses.

A pacemaker is a small device that’s placed in the chest or abdomen to help control abnormal heart rhythms. This device uses electrical pulses to prompt the heart to beat at a normal rate. Pacemakers are used to treat arrhythmias which are problems with the rate or rhythm of the heartbeat. During an arrhythmia, the heart can beat too fast, too slow, or with an irregular rhythm.

During an arrhythmia, the heart may not be able to pump enough blood to the body. This may cause symptoms such as fatigue (tiredness), shortness of breath, or fainting. Severe arrhythmias can damage the body’s vital organs and may even cause loss of consciousness or death.

Dr. J. Rod Gimbel of Cardiology Associates of East Tennessee in Knoxville, Tennessee comments:

“The new Revo MRI pacemaker is a major technological breakthrough for patients who need access to MRI. Providing pacemaker patients with access to MRI allows detection and treatment of serious medical conditions such as stroke, cancer, and a wide variety of important neurologic and orthopedic conditions.”

Individuals over age 65 are twice as likely to need an MRI compared with younger patients, and between 50 and 75 percent of patients with electronic cardiac devices will likely need an MRI over their device’s lifetime. An MRI machine uses a powerful magnetic field to align the magnetization of some atoms in the body, and radio frequency fields to systematically alter the alignment of this magnetization. This causes the nuclei to produce a rotating magnetic field detectable by the scanner and this information is recorded to construct an image of the scanned area of the body. Strong magnetic field gradients cause nuclei at different locations to rotate at different speeds. 3-D spatial information can be obtained by providing gradients in each direction.

MRI provides good contrast between the different soft tissues of the body, which make it especially useful in imaging the brain, muscles, the heart, and cancers compared with other medical imaging techniques such as computed tomography (CT) or X-rays. Unlike CT scans or traditional X-rays MRI uses no ionizing radiation.

Pat Mackin, president of the Cardiac Rhythm Disease Management business and senior vice president at Medtronic adds:

“For the first time, patients will have access to a state-of-the-art pacemaker that is designed to work safely and effectively in an MRI environment. This milestone underscores Medtronic’s ongoing commitment to develop pacemaker technology that provides meaningful differences in patients’ lives.”

Modern pacemakers usually have multiple functions. The most basic form monitors the heart’s native electrical rhythm. When the pacemaker fails to sense a heartbeat within a normal beat-to-beat time period, it will stimulate the ventricle of the heart with a short low voltage pulse. This sensing and stimulating activity continues on a beat by beat basis.

The more complex forms include the ability to sense and/or stimulate both the atrial and ventricular chambers.

Source: Medtronic

Written by Sy Kraft, B.A.