Non Magnetic MRI Conditional External Defibrillator with Reduced Skeletal Muscle Contraction

Coram Technologies, Inc., Pikesville MD

Investigators

Abstract

There are over 36 million MRI scans done each year in the United States, and anesthesia or sedation is used in a significant number of those scans. This is especially true in pediatrics where as many as 28% of MRI scans are done with anesthesia, and the increased use of anesthesia has increased the utilization of MRI. It has long been known that cardiac arrest from ventricular fibrillation can complicate anesthesia administration. Even with modern methods, cardiac arrest still can occur during anesthesia management, with mortality as high as 30%. In addition, cardiac arrest can occur during MRI scans even without anesthesia. There are also MRI-guided interventions that are not currently being performed, such as ablation of ventricular tachycardia, because of the high risk of ventricular fibrillation, and the lack of the availability of immediate defibrillation. Delays in defibrillation occur due to the need for removal of the patient from the scanner, placement onto a stretcher, and relocation to a nearby environment stocked with resuscitation equipment. The defibrillator cannot be near the scanner since the magnet can draw a defibrillator into the bore of the scanner. Defibrillation can be further delayed by uncertainty in diagnosing lethal arrhythmias due to MRI-induced ECG artifacts. Each minute in delay to defibrillation can reduce survival by 5-10%. The unmet clinical need, therefore, is the lack of availability of a system that would allow defibrillation in the scanner room, and ideally in the bore of the scanner itself, thereby minimizing delays in defibrillation. The central hypothesis is that we can develop a defibrillator that would allow defibrillation in the MRI scanner, reducing delays, and also allowing procedures with a higher risk of arrhythmias to be done under MRI guidance. Defibrillation can be done in the scanner because of the MRI compatible properties of the system, and because motion of the patient caused by the shock is substantially reduced by a pre-shock waveform that reduces skeletal muscle contraction, preventing the patient from “jumping” into the scanner bore walls. The overall objective of this proposal is to construct such a defibrillator system, and test the system in swine studies. Coram Technologies has the expertise to accomplish this objective. The preliminary studies that have been done show the feasibility of the critical subsystems. In addition, there likely will be strong patent protection for this technology. The Specific Aims are: Aim 1: To develop a functional prototype of an MRI conditional external defibrillator incorporating the pre-shock muscle conditioning waveform. Aim 2: To test the functionality of the prototype in swine in and out of the MRI scanner. The expected outcomes from this program include the development of a functional prototype that can defibrillate swine both outside and inside the MRI scanner, and is safe to use in the MRI environment at 1.5 and 3T. An exclusive license for a patent covering the technology is also expected to be secured. A commercial version of the prototype will be developed and validated in Phase II. If this project is successful, this defibrillator will likely become a “must have” for any MRI scanner where patient monitoring equipment is used, which is approximately 50% of the total number of MRI scanners.