Detection of rejection after heart transplantation. A computerized precordial mapping experience

A low-cost modular compact personal computer-based system for surface precordial mapping (SPM) developed by the authors was used to detect rejection periods, documented by endomyocardial biopsy (EB), in heart transplant patients on cyclosporine A therapy. Data were collected with a matrix of 35 Ag-AgCl electrodes positioned over the precordio with anatomical references within 12 hours of EB. For each acquisition the authors computed the root mean square waveform from all signals collected to assess the accuracy of the maximum value of the RMS waveform (mRMS) parameter to detect rejection episodes. A mRMS variation of 20% in consecutive mapping acquisitions was the decision criterion. In EB, only presence or absence of acute rejection was considered. Eleven heart transplant patients were studied and 46 acquisitions were done. The mRMS obtained with SPM showed a sensitivity of 69% and a specificity of 91%, with a positive predictive value of 75% and negative value of 88%. The results indicate that surface precordial mapping may be promising for monitoring rejection.