To evaluate short-term and long-term effects by MR imaging at 3T on the technical and functional status of cardiac pacemakers.

Recently, a shift could be observed from cardiac pacemakers being an absolute contraindication to being a relative contraindication for MR imaging at 1.5 Tesla, depending on a patient-per-patient risk-benefit-evaluation, which includes an urgent clinical need for MR imaging (other imaging modalities non-conclusive) and co-morbidities (especially cardiac co-morbidities). At the same time, MR imaging at 3 Tesla is evolving from a research application only to an important imaging modality today.

Using the improved signal-to-noise-ratio, high field MR-Systems with a field strength of 3 Tesla offer a variety of diagnostic advantages to 1.5 Tesla systems. These advantages lead to a higher sensitivity and specificity in diagnosing, foremost neurological, disorders.

In this study, we evaluate the safety of MR imaging of the brain in patients with cardiac pacemakers at 3T.

Inclusion Criteria:

• Urgent need for an MRI examination

• Stable pacemaker physical parameters

  • Battery voltage > 2.7 V
  • Battery impedance < 2000 Ohm
  • Battery estimated remaining lifetime > 6 months
  • Lead impedances 200-2000 Ohm

• Stable pacing parameters

  • Pacing capture threshold <2.5V at a pulse duration of 0.4ms
  • Sensing > 5mV

• Minimum 3 months since pacemaker and lead implantation

Exclusion Criteria:

• History of ventricular tachycardia (VT) or ventricular fibrillation
• Unstable angina
• Myocardial infarction within the previous 3 months
• Cardiothoracic surgery within the previous 3 months
• Presence of an abdominal pacemaker with lead length > 70 cm
• Presence of MRI incompatible bioimplants or other MRI incompatible materials