BOSTON -- Challenging the FDA to keep pace with the advance of so-called "MRI-safe" or "conditional" implantable cardiac defibrillators (ICDs), yet another manufacturer has presented study results showing these devices pose no risk to patients undergoing MRI.
"Regulatory changes are needed to allow for routine MRI in patients with conditional ICDs after proper evaluation by qualified personnel," , from the University of Alabama-Birmingham School of Medicine, commented at a press conference during the Heart Rhythm Society's 36th Annual Scientific Sessions.
Awad's nonrandomized, single-arm results are for an ICD -- Biotronik's Iforia ProMRI ICD System -- that is already in clinical use as a standard ICD but with the MRI-safety feature deactivated until it receives FDA approval.
His findings are similar to randomized results reported earlier at the meeting for another device that is not FDA-approved, Medtronic's Evera MRI.
Both studies "further confirm that if you design a system platform specifically for MRI it should perform well in the MRI environment and hopefully it will open the door to a new era where most devices are designed to meet that standard," said Awad.
The study included 154 patients (mean age 60 years) from 39 U.S. clinical sites who were implanted with the ICD device in the MRI-safe mode.
The MRI-safety mode disables detection and therapy of ventricular arrhythmias and must be turned off after scanning to re-activate the ICD.
After a 5-week waiting period, 148 patients received nonclinically indicated cardiac (25.7%) or thoracic spine (74.3%) 1.5 Tesla MRI scans that were standardized between all centers and "aimed at stressing the device and the whole system as much as possible and increasing the magnitude of the magnetic field to probably the highest one would encounter in a clinical scan," Awad said.
At both 1- and 3-month follow-up there were no adverse outcomes deemed to be related or possibly related to the ICD system or MRI, no significant increases in ventricular capture threshold, or significant decreases in ventricular sensing.
"We didn't detect any changes to pacing or sensing parameters, and most importantly there was no impact on the device's main function which is detecting and treating ventricular arrhythmias. This device platform will allow patients with ICDs to safely undergo MRI in 1.5T scanners for various clinical indications," he concluded.
Disclosures
The study was funded by Biotronik.
Awad had no disclosures.
Two of his co-investigators, J. Michalski and W. Johnson, are paid employees of Biotronik.
Primary Source
Heart Rhythm Society
Source Reference: Awad K, et al "Clinical safety of the IFORIA ProMRI ICD system subjected to 1.5T cardiac or thoracic spine MRI" HRS 2015; LBCT02-04.