Computerized heart allograft-recipient monitoring: a multicenter study.

Department of Surgery, Division of Transplantation, Karl-Franzens University of Graz, Graz, Austria.
Transplant International (Impact Factor: 3.16). 05/2003; 16(4):225-30. DOI: 10.1007/s00147-002-0530-x
Source: PubMed

ABSTRACT Computerized heart allograft recipient monitoring (CHARM) is a unique concept of patient surveillance after heart transplantation (HTx), based on the evaluation of intramyocardial electrograms (IEGMs) recorded non-invasively with telemetric pacemakers. Previous open, single-center studies had indicated a high correlation between CHARM results and clinical findings. The present study was initiated to assess the suitability of CHARM for monitoring the absence of rejection in a blind, multicenter context. During the HTx procedure, telemetric pacemakers and two epimyocardial leads were implanted in 44 patients at four European HTx centers. IEGMs during pacing were recorded and transferred via the Internet to the CHARM computer center, for automatic data processing and extraction of diagnostically relevant information, i.e., the maximum slew rate of the descending part of the repolarization phase of the ventricular evoked response (VER T-slew). The study period comprised the first 6 months after HTx, during which the transplant centers were blind to the CHARM results. A single threshold diagnosis model was prospectively defined to assess the ability of the VER T-slew to indicate clinically significant rejection, which was defined as an endomyocardial biopsy (EMB) grade greater than or equal to 2, according to the grading system of the International Society for Heart and Lung Transplantation. All EMB slides from three centers were reviewed blind by the pathologist of the fourth center in order that agreement among the histological diagnoses at the various centers could be assessed. Totals of 839 follow-ups and 366 EMBs were obtained in 44 patients. Thirty-seven patients were alive at the end of the study period. Age at HTx, EMB grade distribution, and rejection prevalence varied significantly between the centers. Review of the EMB results showed considerable differences with respect to classification of significant rejection. Comparison of average VER T-slew values with and without rejection in the 15 patients who exhibited both states revealed significantly lower values under the influence of rejection (97+/-13% vs 79+/-15%, P<0.0001). Twenty out of the 25 cases with significant rejection were correctly identified by VER T-slew values below a threshold of 98% (sensitivity =80%, specificity =50%, negative predictive value =97%, positive predictive value =11%; P<0.0005). Of the EMBs, 48% could have been saved if the diagnosis model had been used to indicate the need for EMB. A high negative predictive value for the detection of cases with significant rejection has been obtained in a prospective, blind, multicenter study. The presented method can, therefore, be used to supplement patient monitoring after HTx non-invasively, in particular to indicate the need for EMBs. In centers with patient management similar to the ones who participated in the study, this may allow a reduction in the number of surveillance EMBs.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Ventricular intramyocardial electrograms are recorded with electrodes directly from the heart either in intraventricular or epimyocardial position and may be acquired either from the spontaneously beating or from the paced heart. The morphology of these signals differs significantly from that of body surface ECG recordings. Although the morphology shows general characteristics, it additionally depends on different individual impacts. This problem of individual evaluation is briefly discussed. As an appropriate methodology for its solution, personalized referencing based on similarity averaging has been employed. A more general approach may be model-based signal interpretation, which is still under investigation. The preliminary results reveal a promising potential of intramyocardial electrograms for cardiac risk surveillance, e.g., for arrhythmia detection, recognition of rejection events in transplanted hearts, and assessment of hemodynamic performance. Employing implants with telemetric capabilities may render possible permanent and even continuous cardiac telemonitoring. Furthermore, the signals can be utilized for supporting therapy management, e.g., in patients with different kinds of cardiomyopathies. This paper shall demonstrate some preliminary results and discuss the expected potential.
    IEEE transactions on information technology in biomedicine: a publication of the IEEE Engineering in Medicine and Biology Society 03/2008; 13(4):426-32. · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Success in cardiac transplantation has been achieved by the development of improved immunosuppressive therapies, which have led to a concomitant decrease in cardiac allograft rejection and infection. Rejection however continues to be the cause of significant morbidity and mortality particularly in the first year after cardiac transplantation. The endomyocardial biopsy remains an essential tool for its diagnosis. Acute cellular rejection has been a well recognized phenomenon although more recently, the diagnosis of antibody-mediated rejection has gained acceptance, a condition associated with greater graft dysfunction, subsequent development of cardiac allograft vasculopathy and mortality. In this article we review the current status of the diagnosis of cardiac allograft rejection as determined by the traditional endomyocardial biopsy, the more recent advances in the non-invasive evaluation of rejection, detection of circulating antibodies and the treatment of rejection.
    The surgeon: journal of the Royal Colleges of Surgeons of Edinburgh and Ireland 06/2011; 9(3):160-7. · 1.97 Impact Factor
  • Source
    New England Journal of Medicine 04/2010; 362(20):1932-3. · 51.66 Impact Factor

Full-text (2 Sources)

Available from
Aug 29, 2014