Safety of magnetic resonance imaging in patients with cardiac implantable electronic devices with generator and lead(s) brand mismatch

Magnetic resonance imaging (MRI) is a valuable imaging modality for the assessment of both cardiac and non-cardiac structures. With a growing population of patients with cardiovascular implantable electronic devices (CIEDs), 50%–75% of these patients will need an MRI. MRI-conditional CIEDs have demonstrated safety of MRI scanning with such devices, yet non-conditional devices such as hybrid CIEDs which have generator and lead brand mismatch may pose a safety risk. In this retrospective study, we examined the outcomes of patients with hybrid CIEDs undergoing MRI compared to those patients with non-hybrid CIEDs. A total of 349 patients were included, of which 24 patients (7%) had hybrid CIEDs. The primary endpoint was the safety of MRI for patients with hybrid CIEDs as compared to those with non-hybrid devices, measured by the rate of adverse events, including death, lead or generator failure needing immediate replacement, loss of capture, new onset arrhythmia, or power-on reset. Secondary endpoints consisted of pre- and post-MRI changes of decreased P-wave or R-wave sensing by ≥50%, changes in pacing lead impedance by ≥50 ohms, increase in pacing thresholds by ≥ 0.5 V at 0.4 ms, and decreasing battery voltage of ≥ 0.04 V. The primary endpoint of any adverse reaction was present in 1 (4.2%) patient with a hybrid device, and consistent of atrial tachyarrhythmia, and in 10 (3.1%) patients with a non-hybrid device, and consisted of self-limited atrial and non-sustained ventricular arrhythmias; this was not statistically significant. No significant differences were found in the secondary endpoints. This study demonstrates that MRI in patients with hybrid CIEDs does not result in increased patient risk or significant device changes when compared to those patients who underwent MRI with non-hybrid CIEDs.