Refine
Year of publication
- 2012 (13) (remove)
Document Type
Conference Type
- Konferenz-Abstract (7)
- Konferenzartikel (3)
Is part of the Bibliography
- yes (13)
Keywords
- Herzschrittmacher (2)
- Kardiale Resynchronisationstherapie (2)
- Signaltechnik (2)
- AV-Delay (1)
- CRT (1)
- Defibrillator (1)
- Elektrokardiogramm (1)
- Herzinsuffizienz (1)
- Herzmuskelkrankheit (1)
- Telemetrie (1)
Institute
Open Access
- Open Access (12)
- Closed Access (1)
ECG simulators, available on the market, imitate the electric activity of the heart in a simplified manner. Thus, they are suitable for education purposes but not really for testing algorithms to recognize complex arrhythmias needed for pacemakers and implantable defibrillators. Especially certain discrimination between various morphologies of atrial and ventricular fibrillation needs simulators providing native electrograms of different patients’ heart rhythm events. This explains the necessity to develop an ECG simulator providing high-resolution native intracardiac and surface electrograms of in-vivo rhythm events. In this paper we demonstrate an approach for an ECG simulator based on a consumer multichannel soundcard and a corresponding software application for a laptop computer. This Live-ECG Simulator is able to handle invasive electrogram recordings from electrophysiological studies and send the data to a modified external soundcard for subsequent digital to analog conversion. The hardware is completed with an electronic circuit providing level adjustment to adapt the output amplitude to the input conditions of several cardiac implants.
In cardiac resynchronization therapy (CRT) for heart failure, individualization of the AV delay is essential to improve hemodynamics and to minimize non-responder rate. In patients in sinus rhythm having additional disposition to bradycardia, optimization is necessary for both situations, atrial sensing and pacing. Therefore, echo-optimization is the goldstandard but time consuming. Unfortunately, it depends on the particular CRT systems parameter set if the resulting individually optimal AV delays can be programmed or not. Some CRT systems provide a set of AV delays for DDD operation combined with a set of the pace-sense-compensation to optimize the AV delay in DDD and VDD operation. The pace-sense-compensation (PSC) can be defined by the difference of implant-related interatrial conduction intervals in DDD and VDD operation measured in the esophageal left atrial electrogram. In a cohort of 96 CRT patients we found mean PSC of 59-35ms ranging between 0-143ms. As a consequence, allowing 10ms tolerance, AVD optimization is completely impossible in one of the two modes, VDD or DDD operation, in 34 (35%) or 5 (5%) patients with implants restricting the PSC range to 60ms or 100ms, respectively. Thus, we propose companies to provide CRT systems with programmable pace-sense- compensation between 0ms and 150ms.
Für den Erfolg einer kardialen Resynchronisationstherapie der Herzinsuffizienz mit biventrikulär stimulierenden Implantaten ist deren individuelle Programmierung von erfolgsbestimmender Bedeutung. Dies trifft insbesondere auf den Parameter AV-Delay zu. Dessen Optimierung durch Echo-Verfahren ist zeitaufwendig, die Suche nach einfacheren Methoden darum verständlich. Eine solche verspricht der in St. Jude Aggregate implementierte automatische QuickOpt Algorithmus. In-vitro-Untersuchungen unter Einsatz eines elektronischen Herzsimulators sagten jedoch verschiedene ungünstige Eigenschaften vorher. Die eingeschränkte Nutzbarkeit ließ sich auch mit In-vitro-Vergleichen belegen.