Automatic capture verification by charge-neutral sensing

Citation
Va. Kadhiresan et al., Automatic capture verification by charge-neutral sensing, PACE, 22(1), 1999, pp. 73-78
Citations number
6
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Journal title
PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY
ISSN journal
01478389 → ACNP
Volume
22
Issue
1
Year of publication
1999
Part
1
Pages
73 - 78
Database
ISI
SICI code
0147-8389(199901)22:1<73:ACVBCS>2.0.ZU;2-Y
Abstract
Automatic capture verification can prolong pulse generator longevity and in crease patient safety. However, the detection of evoked response following pacing is complicated due to afterpotentials caused by polarization of elec trodes. This study describes a new capture verification scheme, which neutr alizes the charges between the pacing electrodes. The hypothesis of the cha rge-neutral sensing is that the afterpotentials in the ring and the tip are opposite in polarity when pacing in a bipolar mode between ring and tip. S umming the unipolar signals sensed at the tip and the ring should effective ly cancel the afterpotentials. This scheme was implemented in an external c omputer based system and tested during pacemaker implant/replacement on 23 patients during VVI pacing (17 acutely implanted leads and 6 chronic leads) . Surface ECG was recorded to provide a marker for capture and noncapture. The pacing voltage was gradually decreased until a noncapture beat was note d. To avoid fusion beats, the pacing rate was programmed similar to 50% hig her than the intrinsic rate. The evoked response was high pass filtered and the integral average was calculated for both capture and noncapture beats. The system signal to noise ratio (SNR) was expressed as ratio of the minim um integral average of all capture beats to the maximum integral average of all noncapture beats. The system SNR was 8.6 +/- 1.3 (mean +/- S.E.M; rang e 1.5-22.8), indicating that the charge-neutral sensing method has, on aver age, a ninefold safety margin in providing capture verification. Further, e valuation is needed to fully assess this feature in patients with chronic l eads.