Retrospektive Langzeitanalyse zur Verwendung von unipolaren epikardialen Elektroden bei einem Herzschrittmacher mit ventrikulärer „Automatic-Capture™“-Funktion im Kindes- und Jugendalter

Abstract

Objectives: Epicardial pacing is applied regularly in pacemaker (PM) therapy for paediatric patients. Automatic PM algorithms have been developed to increase patient safety. The “Automatic-Capture™” algorithm (AC) measures the ventricular threshold automatically, regulates output voltage and assesses the evoked response on a beat-to-beat basis. This long-term retrospective data analysis examined the feasibility and performance of AC combined with unipolar epicardial pacing leads in paediatric patients with and without congenital heart disease. There has not been any investigation on unipolar epicardial leads used with AC or similar algorithms so far, although small heart size or scar tissue often necessitates the use of unipolar epicardial leads in patients. Methods: The aims of this analysis were (1) to evaluate the extent of successful automatic threshold testing and beat-to-beat analysis in paediatric patients with an AC pacemaker produced by Boston Scientific™ (Insignia™/Altrua™) combined with unipolar epicardial leads over a long period of time, (2) to examine patient and lead characteristics as possible influencing factors on AC performance and (3) to assess PM longevity using AC. Results: 30 patients (aged 0,7 - 20,4 years at PM implantation) were followed up for a median of 3.9 (0.8 - 7.8) years between 2004 and 2012. 10 of these patients received a PM replacement after battery depletion or lead failure, equalling a total of 40 studied PMs. The beat-to-beat analysis functioned well according to routine 12-channel-ECGs and Holter-ECGs in all 40 PMs. The median extent of successful automatic threshold testing in the 40 PMs was 100% (interquartile range 1,1%), in 33 of 40 PMs (82.5%) it was >95%. During follow-up no adverse effects of AC were seen. On univariate analysis, none of the examined patient or lead characteristics (lead model, congenital heart disease, quantity of former heart operations, lead age at PM implantation, patient's age at PM implantation) indicated an influence on AC performance. A comparison between actual AC-PM longevity and theoretical longevity with AC turned off in 5 PMs indicated only slight differences, strongly depending on the average threshold and choice of safety margins in the conventional pacing. Conclusion: Combined with the unipolar epicardial leads used in this analysis, AC worked safely and continuously as intended in paediatric patients over a long period of time.