Electrode‐Heart Interface: Definition of the Ideal Electrode

Abstract

In dual-chamber pacing in order to maintain the advantages of small pulse generator size and volume, and increased longevity, it becomes necessary to reduce pulse generator output. This may be accomplished by optimizing the electrode-heart interface. New electrode designs may reduce polarization losses; perhaps even newer materials should be considered. The results of accumulated data must be applicable to long-term pacing.

Effects of Local Steroid Elution on Chronic Pacing Threshold and Impedance of Endocardial Pacemaker Leads

“…Thus, local steroid elution only seems to in fluence the pacing threshold, but not the pac ing impedance. The impedance did not change with de creasing pulse amplitudes and had only minor increase with longer pulse durations; the latter is probably related to the exponential decay of the pacing impulse [7,8], In accordance with former studies [7][8][9], stable impedance can only occur if there are no pulse-dependent effects such as polarization at the electrode tip. If other modern leads also have a stable impedance pattern, impedance can be gener ally determined independently from the pac ing amplitude.…”

“…The pacemaker calcu lates the impedance from the decay between the lead ing and the trailing edge of the pacing impulse. This decay depends not only on the capacitor and tissue resistance of the pulse generator, but also on the polari zation occurring at the electrode tip [7][8][9]. Whereas the former two variables are nearly constant, polarization varies with the pacing impulse and increases with decreasing pulse amplitudes [9], Impedance was deter mined at 0.8, 1.6, 2.5, 5.0, and 8.0 V pulse amplitude in combination with 0.05,0.25,0.5, 1.0 ms pulse dura tion.…”

Die intraoperativ gemessene Stimulationsimpedanz von Schrittmacherelektroden ist kein Prädiktor für ihren Langzeitverlauf

“…Die verschiedenen Impedanzverläufe sind überwiegend auf Unterschiede des dem Elektrodenkopf anliegenden Endo-, Myokards bzw. auf die unterschiedlichen Interaktionen zwischen Elektrodenkopf und Endo-, Myokard zurückzuführen, da andere Determinanten für die Stimulationsimpedanz wie Polarisationsspannung und Leiterwiderstand -beides beeinflußt die Impedanz ungünstig -bei heutigen Elektroden minimiert sind (10,15,19).…”

“…Der theoretisch nachweisbare inverse Zusammenhang zwischen Stimulationsimpedanz und Stimulationsstrom und die damit zu erzielende Verlängerung der Funktionszeit gewinnt in der Schrittmachertherapie zunehmende klinische Bedeutung (1,10,19): Zum einen wurden speziell hochohmige Schrittmacherelektroden entwickelt (12,18), deren hohe Stimulationsimpedanz bei gleichen Stimulationsimpulsen zusätzlich den Stimulationsstrom vermindert (3,4,7). Zum anderen werden die patientenbezogenen Faktoren optimiert, z.…”

Polarization Potentials Causing Pacemaker Oversensing

“…7 Epicardial lead systems are not, per se, associated with higher polarization potentials. In fact, the epicardial electrode area of 12 mm 2 is larger than the average endocardial distal tip electrode area of 6-10 mm 2 and should therefore have a lower current density value.…”