Automatic capture verification in ICD lead systems using intracardiac ventricular evoked response and reduced coupling capacitance.
OBJECTIVE
Intracardiac ventricular evoked-response (ER) signals detected by implanted cardioverter defibrillator (ICD) lead systems were investigated for automatic capture verification (AC).


METHODS
ER signals were evaluated with an external pacing system equipped with a reduced coupling capacitance (CC=2.2 microF) in the pacing output circuit during ventricular step-down threshold testing at 0.4 ms pulse duration. Real-time pacing markers, surface ECG and intracardiac electrograms pre- and post-filtering were digitally recorded.


RESULTS
Twenty consecutive patients, age 61+/-12 years, with leads from two different manufacturers were tested - 10 were implanted with acute leads (AL) and 10 with chronic leads (CL). The analysis was based on the ER amplitude during capture and on the ER-to-afterpotential ratio (SAR), with SAR>2 as the criterion for successful capture detection. ER amplitudes (median and range) were 8.1 mV (2.1-19.5 mV) for AL and 8.3 mV (3.7-14.2 mV) for CL. SAR values (median and range) were 48.0 (2.5-682.6) for AL and 13.2 (6.3-35.9) for CL, indicating that AC could successfully be applied in all patients.


CONCLUSIONS
Reducing the pacing CC allows adequate ER detection for automatic capture verification on non-selected ICD lead systems. The effect of high-voltage shock treatment on ER signal detection requires further investigation.
Sperzel
J
J
Kerckhoff-Klinik, Department of Cardiology and Electrophysiology, Benekestrasse 2-8, 61231, Bad Nauheim, Germany. Johannes.Sperzel@kerckhoff.med.uni-giessen.de
Pitschner
H F
HF
Schwarz
T
T
König
A
A
Zhu
Q
Q
Neuzner
J
J
D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005071:Evoked Potentials; D006801:Humans; D008875:Middle Aged