Heart Graft Monitoring by the Ventricular Evoked Response

Abstract

MAHAUX, V., ET AL.: Heart Graft Monitoring by the Ventricular Evoked Response. Monitoring of the neg ative slew rate of the evoked T wave has been proposed as a noninvasive diagnostic tool to follow heart transplant recipients. The clinical contribution of this measurement on telemetrically recorded, paced unipolar ventricular electrograms was evaluated in the detection of grade 3 acute allograft rejection. Thir teen patients undergoing heart transplantation received a DDD pacemaker connected to two epimyocardial leads. Electrograms were recorded and digitized after each endomyocardial biopsy (EMB). The max imum slew rate of the descending slope of the repolarization phase (RSP) was extracted and normalized. A 20% downward shift of RSP from the reference value was considered abnormal. Results of signal pro cessing were blinded during the first 6 months. Eleven patients completed the 6 months blinded period and two patients died. A total of 101 EMB were graded according to the International Society for Heart and Lung Transplantation classification. Grade 3 was assigned to 9 EMB. A significant difference was found between RSP values measured during grade 3 rejection episodes and other RSP values (P < 0.001). A diagnostic model consisting of a single threshold test confirmed the ability ofRSP to predict significant signs of rejection on EMB (P < 0.0001). The sensitivity of RSP in detecting grade 3 rejections was 100%, specificity was 81 %, negative predictive value 100%o, and positive predictive value 35%. The use ofRSP as a noninvasive monitoring tool to pose the indication for a biopsy would avoid 73% of EMB. Monitor ing of transplanted hearts based on the analysis of the ventricular evoked response is promising and may markedly reduce the number

Noninvasive monitoring of rejection therapy based on intramyocardial electrograms after orthotopic heart transplantation. Initial experience with 14 cases

“…In the United States, monitoring of cardiac transplant patients varies from one centre to another, and in addition to biopsy, other indicators and clinical signs of rejection are taken into consideration [14]. Noninvasive rejection monitoring would notably improve the quality of life of cardiac transplant recipients.…”

“…Because the data needed for analysis must be collected several times a week or even daily, the technique should be noninvasive, reliable, non-observer-dependent and, if possible, cost effective. As shown by research and clinical experience, intramyocardial electrogram recording using a specially adapted pacer and echocardiography seems to be the most promising tool for noninvasive cardiac transplant monitoring [10][11][12][13][14].…”