Do we need MR conditional pacemakers?

Magnetic resonance imaging (MRI) is a widely accepted tool for the diagnosis of a variety of disease states. However, due to safety concerns the presence of an implanted cardiac pacemaker is considered to be a contraindication to MRI in most medical centres. The increasing number of implanted pacemakers and the estimated over 50% probability that a pacemaker patient may be a candidate for an MRI increase the need for safe scanning of pacemaker patients. Over the last ten years a major effort has been made to understand the potential risks. The influences from the three electromagnetic fields on pacemakers are versatile and will be summarised. The research in this area has helped to predict the risks of an MRI scan in patients with conventional pacemakers, and has also stimulated pacemaker manufacturers to improve their devices with the goal of providing MR conditional devices. Since autumn 2008 the first approved MR conditional pacemakers have been on the market and other devices are likely to follow this trend. However, the vast majority of devices are still not approved for MRI, a situation which will take several years to change. It is thus important that a solution be also found for these patients. Several studies including over 500 patients with a pressing need for MRI have been performed at different experienced centres. On the basis of those data various organisations in MRI fields have proposed guidelines for MRI in patients who fulfill given requirements. However, at present, non- MRI modalities should be considered, whenever possible, for diagnosis in pacemaker recipients with conventional devices. If other imaging modalities are not adequate, MRI with careful monitoring and preparation for adverse events may be considered only at experienced centres. With the wider availability of MR conditional devices, the risks of MRI are greatly reduced and non-tertiary centres will be able to perform these investigations. In any case, rapid progress in the field of MR conditional pacing is desirable.