Real World Evaluation of Ventricular Fibrillation Detection after Magnetic Resonance Imaging in Patients with an MR Conditional ICD or CRT-D

Background:

MR conditional implantable cardioverter defibrillators (ICDs) and cardiac resynchronization therapy (CRT-Ds) devices were recently introduced to the market in 2015. Little published data exists on sensing and detection of ventricular fibrillation (VF) after clinical MRI scanning.

Purpose:

We sought to further understand the VF sensing performance following MRI exposure in these MR conditional devices among a large real-world cohort.

Methods:

De-identified remote transmissions were used to identify MR conditional ICDs and CRT-Ds with MR exposure (MRI safe scannig mode enabled for > 20 min) and subsequent spontaneous ventricular tachyarrhythmia episodes noted in the VF zone. All VF episodes with stored electrogram episodes available were reviewed and classified by an independent Episode Review Committee (ERC) to determine 1) the rhythm, and 2) the presence of any detection delay in seconds. A clinically significant detection delay was defined as ≥ 5 seconds.

Results:

Among 58,054 MR conditional devices, 2,056 patients had at least one presumed MR scan. Of the 2,056 patients, 138 had a total of 340 device-detected tachyarrhythmia episodes. Fifteen episodes from 12 subjects were classified as a true spontaneous VF event, of which none were noted to have a detection delay ≥ 5 seconds or significant VF undersensing.

Conclusion:

In this real-world large-scale study, there was no observed impact on sensing and detection performance following MRI exposure. These data further demonstrate the device performance of the MR conditional tachyarrhythmia therapy systems.