Can cardiac pacemakers and magnetic resonance imaging systems co-exist?

This editorial refers to ‘ In vivo heating of pacemaker leads during magnetic resonance imaging’† by R. Luechinger et al ., on page 376 One of the earliest lessons learned by physicians and technologists working in the field of magnetic resonance imaging (MRI) is that cardiac pacemakers represent a strict contraindication to performing an examination. However, there are multiple examples of implants and devices that previously were contraindicated for MRI and are now allowed within specific guidelines. These include neurostimulation systems, cochlear implants, a drug infusion pump, and a bone fusion stimulator. Because of expanding clinical indications, both MR and pacemaker technology has steadily advanced. It is no surprise then that these two powerful technologies might clash. There has been a steady increase in the number of pacemakers implanted in the United States and worldwide. More than 900 000 pacemakers were implanted worldwide in 2003, and since 1999 implantation rates have increased 5–6% per year. MR systems have been increasing in number as well. There are now ∼15 000 MR systems worldwide, and 35 million MR studies performed yearly. MR is an important diagnostic tool in musculoskeletal, central nervous system, and oncological disorders. It is also rapidly expanding into the cardiovascular arena. Because of its varied clinical applications there are times when denying MR examinations to patients with a pacemaker may have a significant impact on public health. The patients may be subjected to a more invasive or less accurate test which may influence the quality of healthcare. A 1999 Japanese study found that 17% of patients with pacemakers were denied MRI in the previous year.1 Applying those numbers worldwide, the effect could influence the healthcare of over 1 million people. Notably, harmful effects to patients have been documented. To date there have been 10 deaths attributed to … *Corresponding author. Tel: +1 918 592 0999; fax: +1 918 878 2436. E-mail address : martin{at}oklahomaheart.com