Abstract 2330: Novel Implantable Device to Detect Allograft Rejection after Heart Transplantation
The Soul Mate™ is an implantable system which records intramyocardial electrograms (IMEG) with remote wireless data communication. The purpose of this study was to assess the efficacy of this system to detect early allograft rejection (AR). Five dogs underwent heterotopic cervical heart transplantation and Soul Mate™ Cardiac Rejection Device (CRD) implantation. The IMEG data were automatically recorded from 3 leads in 6 different lead configurations. Among 9 calculated IMEG parameters, the percent change in the average area under the QRS dominant peak from all 6 configurations was used to calculate a rejection grade (CG). Immunosuppressive therapy was used early on to record baseline data and then was discontinued to induce graft rejection. For comparison, biopsy specimens were taken at regular intervals from the allograft to determine ISHLT biopsy grade (BG). Figure⇓ shows the typical time course in one study comparing BG and CG indices of rejection. Significant correlation (r = 0.835, p < 0.001) was obtained between the BG and CG. The stronger correlation (r = 0.931, p < 0.001) between the BG and CG data obtained one day prior to biopsy suggests possible higher AR sensitivity with the CRD. When compared with serial biopsy, the Soul Mate™ system demonstrated at least equivalent capability for detecting AR after heart transplantation in a canine model. CRD data was recorded with little effort with results available via a secure internet connection contrasting the cost and complexity of biopsy grading. This system has the potential to be used clinically as a continuously monitoring noninvasive tool for detecting early AR.