Analysis of myocardial evoked potentials in relation to ergometric load and heart rate for use in frequency-adaptive cardiac pacemakers
Wetzig, T.; Fischer, G.; Worth, H.; Hardt, R.; Hubmann, M.; Bolz, A.; Schaldach, M.
Biomedizinische Technik. Biomedical Engineering 40(1-2): 9-13
1995
ISSN/ISBN: 0013-5585 PMID: 7703348 Document Number: 451214
The aim of this study was to evaluate the ventricular evoked response (VER) measured with unipolar fractally coated pacing leads for use with rate-responsive pacemakers. To this end, the morphology of the VER, its variation with pacing rate and various levels of physical loading, and the long-term stability of the signal were studied using the telemetric features of implantable pacemakers. Fractally coated electrodes were used in order to minimize the stimulation artefact, thus enabling a reliable unipolar measurement of the VER. The VER shows uniform basic morphology, and remains virtually unchanged after 3 months; moreover, frequency and load-dependent changes of VER morphology were identical for all patients. A special programming device has been developed to evaluate a rate adaptive algorithm for optimizing the pacing rate to the current loading situation, and was successfully tested in two patients. The algorithm was shown to be capable of calculating a heart rate adequate for haemodynamic demand.