New research shows that people who have implanted heart-assist devices, such as pacemakers and defibrillators, may safely use magnetic resonance imaging .
Pacemakers and defibrillators are battery-operated implantable devices used to regulate an abnormal heartbeat known as arrhythmia. Researchers say doctors have feared that the electromagnetic fields of the MRI may heat up metal components of the device, dislodge it, and cause tissue damage, device malfunction, or possibly death. However, many people with these heart devices would benefit from early cancer and other disease detection or minimally invasive surgery with MRIs.The researchers tested nine pacemakers, 18 defibrillators, and 40 lead systems, which are the electrical components that connect the device to the heart muscle. Each of these was tested under various electro-magnetic field strengths in models filled with salt water or gel to simulate the inside of the human body.
Study results show most modern heart-assist devices are safe and perform well in standard- and maximum-strength MRIs. The lead systems of the devices never heated more than 9 degrees Fahrenheit, which is not enough heat to damage tissue. They also found the pull of the electromagnetic field on the heart devices was negligible. This is due to titanium being the most widely used metal for modern pacemaker casings, which is almost nonmagnetic. Tough scar tissue also forms around heart devices after implantation, therefore preventing movement without surgical incisions.
Overall, the study finds, MRI testing yielded good images with minor distortions or abnormalities in the pictures and they hope that further research will produce devices that are prospectively designed to be MRI safe eventually making implantable heart devices MRI compatible, so that all patients can benefit from the advantages of both technologies.
