title: [Measuring bioelectric myocardial impedance as a noninvasive method for diagnosis of graft rejection after heart transplantation].
abstract: 12 beagle dogs underwent neck-heart transplantation and were immunosuppressed with cyclosporine and methylprednisolone. Intramyocardial impedance was determined twice daily with four screw-in electrodes in the right and left ventricle. Transmyocardial biopsies and the intra-myocardial electrogram (IMEG) were performed as reference methods. 19 rejection episodes were induced. When acute rejection was seen in histology the animals were treated with pulsed 125 mg methylprednisolone over 5 consecutive days and immunosuppression was raised to sufficient levels. Successful treatment of rejection was controlled by biopsy. All hearts showed a uniform decrease of impedance of about 28.3% +/- 5.5% immediately after implantation, then reaching a stable plateau after 7 to 8 days. Impedance values then remained unchanged as long as rejection was absent. Biopsy findings of grade 1A to 1B (ISHLT) were accompanied by a statistically significant increase of impedance of 12.2% +/- 2.5%, of grade 2 to 3A of 19.2% +/- 3.2%, and of grade 3B to 4 of 27.0% +/- 2.9%. Sensitivity was 95%, specificity 91%. Successful treatment of rejection led to a uniform decrease of impedance to intramyocardial impedance for high frequencies can reliably indicate alterations of the cell membrane and the intracellular space during acute cardiac allograft rejection. The amount of increase of impedance is a reliable noninvasive parameter to graduate acute cardiac allograft rejection. The success of treatment of rejection can also be monitored by impedance. This noninvasive method is applicable for telemetric rejection monitoring via an implantable device, which would allow continuous rejection surveillance of a patient at home without hospital admission.
authors.affiliation: Abt. Herz-, Thorax- und Gefässchirurgie, Deutsches Herzzentrum Berlin.
authors.forename: R
authors.initials: R
authors.lastname: Pfitzmann
authors.forename: J
authors.initials: J
authors.lastname: Müller
authors.forename: O
authors.initials: O
authors.lastname: Grauhan
authors.forename: T
authors.initials: T
authors.lastname: Cohnert
authors.forename: R
authors.initials: R
authors.lastname: Hetzer
mesh_terms: D000818:Animals; D002307:Cardiography, Impedance / Q000187:drug effects / Q000295:instrumentation; D004285:Dogs; D004567:Electrodes, Implanted; D006084:Graft Rejection / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D016027:Heart Transplantation / Q000276:immunology* / Q000473:pathology; D007166:Immunosuppressive Agents / Q000008:administration & dosage; D009206:Myocardium / Q000473:pathology; D009333:Neck; D012680:Sensitivity and Specificity; D016042:Transplantation, Heterotopic / Q000276:immunology* / Q000473:pathology
chemical_list: D007166:Immunosuppressive Agents
vernacular_title: Die Messung der bioelektrischen myokardialen Impedanz als nichtinvasive Methode zur Abstossungsdiagnostik nach Herztransplantation.