[Analysis of myocardial evoked potentials in relation to ergometric load and heart rate for use in frequency-adaptive cardiac pacemakers].
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.
Wetzig
T
T
Zentralinstitut für Biomedizinische Technik, Universität Erlangen-Nürnberg.
Fischer
G
G
Worth
H
H
Hardt
R
R
Hubmann
M
M
Bolz
A
A
Schaldach
M
M
D000368:Aged; D000369:Aged, 80 and over; D004562:Electrocardiography / Q000295:instrumentation*; D004566:Electrodes; D005080:Exercise Test / Q000295:instrumentation*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D012984:Software