Issue |
J Extra Corpor Technol
Volume 23, Number 3, September 1991
|
|
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Page(s) | 49 - 55 | |
DOI | https://doi.org/10.1051/ject/199123349 | |
Published online | 21 August 2023 |
Original Article
Electric Impedance Recording - A Noninvasive Method of Rejection Diagnosis
German Heart Institute, Berlin, Germany
* Address correspondence to: Johannes Mueller, MD, German Heart Institute, Berlin, Cardiovascular Surgery, D-1000, Berlin, Germany
The recording of electric tissue impedance reflects membrane function and changes of volume and electrolytes in intra-and extra-cellular space. The purpose of this study was to determine if acute cardiac allograft rejection can be diagnosed from alteration of electric transmyocardial impedance (ETMI). Nine Beagle dogs received a heterotopic neck heart transplant. The animals were immunosuppressed with cyclosporine and steroids for the first three postoperative days. ETMI was recorded twice daily. Transcutaneous biopsies were performed whenever the impedance varied by more than 10%. All hearts showed a uniform impedance decrease immediately after transplantation, reaching a stable plateau after three days. A subsequent increase of impedance by 12.4 +/-2.9% was accompanied by a histological diagnosis of mild rejection. A further increase of 23.2 +/-2.6% histologically showed acute moderate rejection. After treatment with steroids the impedance reached the basic plateau again. Compared with the biopsy the sensitivity and specificity were 100%. The results indicate that the inflammatory process of cardiac allograft rejection can be detected with this method. This technique will be clinically applicable when an implantable telemetric device for recording the impedance and its transmission will be developed.
© 1991 AMSECT
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