Automatic ventricular threshold measurement in children with epicardial pacing leads.

BACKGROUND: The aim of the study was to evaluate the safety and reliability of automatic ventricular pacing threshold measurement, the Medtronic Capture Management (CM), in children with epicardial pacing leads. CM has not been recommended for use with epicardial leads due to lack of pertinent data. METHODS: During a 2-year study period, 34 children (mean age 6.1 years, range 0 days to 17.7 years) with epicardial leads were prospectively enrolled. The CM measurements were compared with in-office ventricular pacing threshold measurements. Thirty bipolar and five unipolar epicardial leads were assessed. RESULTS: CM measurements were successful and reliable in 30 out of 35 leads (86%). The mean threshold with CM was 1.16 V (95% CI 1.07-1.26 V), and with standard measurement was 1.18 V (95% CI 1.09-1.28 V), at a pulse width of 0.40 ms. The reasons for failure were evoked response undersensing in two cases (5.7%), and high intrinsic rate in one case. High pacing thresholds prevented accurate CM measurements in two cases. CONCLUSIONS: CM automatic threshold measurements are consistent with standard ventricular pacing threshold measurements in children with epicardial leads. We recommend a period of monitoring CM performance before programming it to adjust output according to automatic threshold measurements, in order to find the patients in whom it does not work. The CM feature provides increased pacing safety when it measures well (86% of leads). A larger study is needed to prove the tendency for extending battery life in children with epicardial leads.