Journal Article

Do daily threshold trend fluctuations of epicardial leads correlate with pacing and sensing characteristics in paediatric patients?

Maren Tomaske, Paul Harpes, Ali Dodge-Khatami, Nadja Amacker and Urs Bauersfeld

in EP Europace

Published on behalf of European Heart Rhythm Association of the European Society of Cardiology (ESC)

Volume 9, issue 8, pages 662-668
Published in print August 2007 | ISSN: 1099-5129
Published online June 2007 | e-ISSN: 1532-2092 | DOI: http://dx.doi.org/10.1093/europace/eum100
Do daily threshold trend fluctuations of epicardial leads correlate with pacing and sensing characteristics in paediatric patients?

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Aims To evaluate whether the magnitude of daily ventricular pacing threshold fluctuations (Δfluctuation) in trend graphs of stored diagrams correlate with ventricular threshold and sensing changes over time.

Methods and results A total of 56 children received AutoCapture® devices (St. Jude Medical, Sylmar, CA, USA) connected to steroid-eluting epicardial leads. Maximum lead age at study closure was 12.2 years (median 4.0). Telemetry data and daily Δfluctuation were obtained every 6 months. Regression slope coefficients and mean values of repeated measurements were calculated for each patient's course. High daily Δfluctuation correlated with higher pacing thresholds (ρ = 0.68, P < 0.001), lower impedances (ρ = −0.38, P = 0.004), and a Δfluctuation-incline (ρ = 0.34, P = 0.01) over time. Furthermore, a Δfluctuation-incline correlated with a pacing threshold-incline (ρ = 0.34, P = 0.01). No correlation was observed for ventricular sensing. Higher daily Δfluctuation were observed if lead age was > 5 years compared with ≤ 5 years (0.75 vs. 0.55 V@0.5 ms, P = 0.028).

Conclusion High amplitudes of daily Δfluctuation correlate with higher and increasing pacing thresholds and lower impedances. Theoretically, this results from electrode microinstability on the epicardial surface. A decrease of the steroid-eluting potency of the electrode can be hypothesized to cause higher daily Δfluctuation beyond a lead age of 5 years. Potential implications of marked daily Δfluctuation are short-term follow-up and lead replacement in the presence of high pacing thresholds.

Keywords: Pacemaker; Threshold tracking; AutoCapture; Epicardial pacing leads; Paediatric

Journal Article.  3808 words.  Illustrated.

Subjects: Cardiovascular Medicine

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