Introduction: Computerized heart allograft rejection monitoring (CHARM) used for non-invasive rejection monitoring in heart transplant recipients is based on the analysis of ventricular evoked response (VER) signals. The aim of this study was to evaluate the prognostic validity of the Tslew(C), a parameter calculated from the VER.
Methods: During orthotopic heart transplantation, 2 unipolar fractally coated screw-in leads were implanted epimyocardially, one to the left and one to the right ventricle, and connected to a telemetric pacemaker. Recordings of intramyocardial electrograms were performed routinely at the hospital. Data processing was done, artifacts were eliminated, and trend curves of the patients were displayed. Tslew(C) was calculated from the tangent of VER and evaluated from 105 patients. The patients were divided into survivor and non-survivor groups. For statistical analysis, the 2-tailed t-test was performed.
Results: Patients in the non-survivors group compared with the control group showed a significantly lower Tslew(C) in the final follow-up (p < 0.001). The differences were even more impressive in patients with recorded intramyocardial electrograms 30 days before death or with a cardiac reason for death. Tests were performed to find an optimal prognostic threshold of the Tslew(C), and the value of 26 mV was finally found.
Conclusion: Tslew(C) can function as prognostic factor after orthotopic heart transplantation. Further studies should be initiated to provide the prognostic threshold so that patients would not be forced to show up routinely every 4 weeks for follow-up visits. Patients would only have to be admitted to the hospital if the Tslew(C) were less than this prognostic threshold.