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Experiences with a telecare platform integration of ZigBee sensors into a middleware platform
(2012)
Cardiac resynchronization therapy (CRT) with biventricular (BV) pacing is an established therapy in approximately two-thirds of symptomatic heart failure (HF) patients (P) with left bundle branch block (LBBB). The aim of this study was to evaluate left atrial (LA) conduction delay (LACD) and left ventricular (LV) conduction delay (LVCD) using pre-implantational transesophageal electrocardiography (ECG) in sinus rhythm (SR) CRT responder (R) and non-responder (NR).
Methods: SR HF P (n=52, age 63.6±10.4 years; 6 females, 46 males) with New York Heart Association (NYHA) class 3.0±0.2, 24.4±7.1 % LV ejection fraction and 171.2±37.6 ms QRS duration (QRSD) were measured by bipolar filtered transesophageal LA and LV ECG recording with hemispherical electrodes (HE) TO catheter (Osypka AG, Rheinfelden, Germany). LACD was measured between onset of P-wave in the surface ECG and onset of LA deflection in the LA ECG. LVCD was measured between onset of QRS in the surface ECG and onset of LV deflection in the LV ECG.
Results: There were 78.8 % SR CRT R (n=41) with 171.2±36.9 ms QRSD, 73.3±25.7 ms LACD, 80.0±24.0 ms LVCD and 2.3±0.5 QRSD-LVCD-ratio. SR CRT R QRSD correlated with LACD (r=0.688, P<0.001) and LVCD (r=0.699, P<0.001). There were 21.2 % SR CRT NR (n=11) with 153.4±22.4 ms QRSD (P=0.133), 69.8±24.8 ms LACD (n=6, P=0.767), 54.2±31.0 ms LVCD (P<0.0046) and 3.9±2.5 QRSD-LVCD-ratio (P<0.001). SR CRT NR QRSD not corre-lated with IACD (r=-0.218, P=0.678) and IVCD (r=0.042, P=0.903). During a 22.8±21.3 month CRT follow-up, the CRT R NYHA class improved from 3.1±0.3 to 1.9±0.3 (P<0.001). In CRT NR, NYHA class not improved (2.9±0.4 to 2.9±0.2, P=1) during 11.2±9.8 months BV pacing.
Conclusions: Transesophageal LA and LV ECG with HE can be utilized to analyse LACD and LVCD in HF P. Pre-implantational LVCD and QRSD-LVCD-ratio may be additional useful parameters to improve P selection for SR CRT.
Capture threshold (CT) for transesophageal left atrial (LA) pacing (TLAP) and transesophageal left ventricular (LV) pacing (TLVP) with conventional cylindrical electrodes (CE) are higher than TLAP feeling threshold (FT). Purpose of the study was to evaluate focused TLAP CT and FT for supraventricular tachycardia (SVT) initiation and focused TLVP CT for cardiac resynchronisation therapy (CRT) simulation.
Methods: SVT initiation in patients (P) with palpitations (n=49, age 47 ± 17 years) was analysed during spontaneous rhythm and during focused bipolar TLAP with atrial constant current stimulus output, distal CE and three or seven 6 mm hemispherical electrodes (HE) (TO, Osypka AG, Rheinfelden, Germany). CRT simulation in heart failure P (n=75, age 62 ± 11 years) was evaluated by focused bipolar TLAP and/or TLVP with ventricular constant voltage stimulus output and different pacing mode.
Results: Focused electrical pacing field between CE and HE (n=28) allowed low threshold TLAP with 8.0 ± 2.6 mA CT at 9.9 ms stimulus duration (SD) which was lower than 9.2 ± 4.5 mA FT at 9.9 ms SD. Focused electrical pacing field between HE and HE (n=21) allowed low threshold TLAP with 8.1 ± 2.2 mA CT at 9.9 ms SD which was lower than 9.8 ± 5.0 mA FT at 9.9 ms SD. SVT initiation by programmed AAI TLAP was possible in 23 P and not possible in 26 P. CRT simulation was evaluated with TLAP and TLVP with VAT, D00 and V00 pacing mode and 95.5 ± 10.9 V TLVP CT at 4.0 ms SD.
Conclusions: Programmed focused AAI TLAP allowed initiation of SVT with very low CT and high FT and focused electrical pacing field between CE-HE and HE-HE.CRT simulation with focused TLAP and/or TLVP with VAT, D00 and V00 pacing mode may be a useful technique to detect responders to CRT.
Cardiac resynchronisation therapy (CRT) with biventricular pacing (BV) is an established therapy for heart failure (HF) patients with interventricular conduction delay (IVCD). The aim of the study was to evaluate transesophageal IVCD and left ventricular (LV) pacing with directed electrical pacing field (EPF) in HF patients.
Methods: HF patients were analysed with bipolar transesophageal LV electrocardiogram recording and LV pacing with constant voltage stimulus output, 4 ms stimulus duration, distal cylindrical electrode (CE) and seven 6 mm hemispherical electrodes (HE) with 15 mm electrode distance (TO, Dr. Osypka, Rheinfelden, Germany).
Results: LV electrocardiogram recording with HE-HE and CE-HE evaluated a mean IVCD of 79.9 ± 36.7 ms. Directed EPF with CE-HE and HE-HE allowed LV VAT (n=12) and LV D00 pacing (n=5) with a mean effective capture output of 97.35 ± 6.64 V. In 15 responders with IVCD of 87 ± 33 ms arterial pulse pressure (PP) increased from 65 ± 24 mmHg to 79 ± 27 mmHg (p < 0.001). EPF was simulated with finite element method.
Conclusions: Transesophageal LV electrocardiography and directed EPF pacing with CE and HE allowed the evaluation of IVCD and PP to select patients for BV pacing.
Termination of atrial flutter (AFL) is not possible in all AFL patients (P) with transesophageal left atrial pacing (TLAP) with undirected electrical pacing field (EPF) and high atrial pacing threshold. Purpose of the study was to evaluate bipo-lar transesophageal left atrial electrocardiography (TLAE) and TLAP with directed EPF for evaluation and termination of AFL with and without simultaneous transesophageal echocardiography (TEE).
Methods: AFL P were analysed using either a TO electrode with one cylindrical (CE) and three or seven hemispherical electrodes (HE) or TEE electrode with four HE (Osypka, Rheinfelden, Germany). Burst TLAP cycle length was between 200msand 50ms.
Results: AFL cycle length was 233±30 ms with mean ventricular cycle length of 540±149 ms. AFL could be terminated by rapid bipolar TLAP with directed EPF using HE-HE and CE-HE with induction of atrial fibrillation (AF), induction of AF and spontaneous conversion to sinus rhythm and direct conversion to sinus rhythm. Directed EPF was simulated with finite element method.
Conclusions: AFL can be evaluated by bipolar TLAE. AFL can be terminated with rapid TLAP with directed EPF with and without simultaneous TEE. Bipolar TLAE with rapid TLAP is a safe, simple and useful method for evaluation and termination of AFL.
Introduction: Cardiac resynchronization therapy (CRT) with left ventricular (LV) pacing is an established therapy for heart failure (HF) patients (P) with ventricular desynchronisation and reduced LV ejection fraction (EF). The aim of this study was to test the utilization of the transesophageal approach to measure arterial pulse pressure (PP) during LV pacing and electrical interventricular conduction delay (IVCD), to better select patients for CRT.
Methods: 32 HF patients (age 64 ± 10 years; 5 females, 27 males) with New York Heart Association (NYHA) class 2.8 ± 0.6, 27 ± 11 % LV EF and 155 ± 35 ms QRS duration were analysed with semi-invasive left cardiac pacing and electrocardiography. Esophageal TO8 Osypka catheter of 10.5 F diameter was perorally applied to the esophagus and placed in the position of maximum left atrial (LA) deflection and maximum LV deflection to measure PP with VAT or D00 pacing modes.
Results: Temporary transesophageal LV pacing was possible with VAT mode (n=16) and D00 mode (n=16) in all patients. In 15 Δ-PP-responders, PP was higher during LV pacing on than LV pacing off (78.3 ± 26.6 versus 65.9 ± 23.7 mmHg, P < 0.001) and NYHA class improved from 3.1 ± 0.35 to 2.1 ± 0.35 (P < 0.001) during 29 ± 26 month biventricular (BV) pacing follow-up (6 Medtronic and 9 Boston BV pacing devices). In 17 Δ-PP-non-responders, PP was not higher during LV pacing on than LV pacing off (61.5 ± 23.9 versus 60.9 ± 23.5 mmHg, P = 0.066). IVCD was significant longer in Δ-PP-responders than in Δ-PP-non-responders (87 ± 33 ms versus 37± 29 ms, P < 0.001).
Conclusion: Semi-invasive transesophageale LA and LV pacing with D00 and VAT mode and LV electrogram recording may be useful techniques to predict CRT improvement.
Introduction: Cardiac resynchronisation therapy (CRT) with atrioventricular (AV) and interventricular (VV) optimized biventricular pacing (BV) is an established therapy for heart failure (HF) patients with electrical interventricular conduction delay (IVCD). The aim of the study was to compare AV and VV delay optimization with cardiac output (CO) and acceleration index (ACI) impedance cardiographic (ICG) methods.
Methods: HF patients with IVCD 86.8 ± 33 ms (n=15, age 66 ± 10 years; 2 females, 13 males), New York Heart Association (NYHA) functional class 3.1 ± 0.4, left ventricular (LV) ejection fraction 21.3 ± 7.8 % and QRS duration 176.1 ± 31.7 ms underwent AV and VV delay optimization with CO and ACI methods (Cardioscreen, Medis GmbH, Ilmenau, Germany). After evaluation of optimal AV delay, we evaluated optimal VV delay during simultaneous LV and right ventricular (RV) pacing (LV=RV), LV before RV pacing (LV-RV) and RV before LV pacing (RV-LV).
Results: Optimal VV delay was -12.3 ± 25.9 ms LV-RV pacing with VV delay range from -80 ms LV-RV pacing to +20 ms RV-LV pacing and RV=LV pacing. Optimal AV delay after atrial sensing was 108.6 ± 20.3 ms (n=14) and optimal AV delay after atrial pacing 190 ± 14.1 ms (n=2) with AV delay range from 80 ms to 200 ms. RV versus BV pacing mode resulted in improvement of CO from 3.4 ± 1.2 l/min to 4.4 ± 1.4 l/min (p<0.001) and ACI from 0.667 ± 0.227 1/s² to 0.834 ± 0.282 1/s² (p<0.002). During 34 ± 26 month BV pacing, the NYHA class improved from 3.1 ± 0.4 to 2.1 ± 0.4 (p<0.001).
Conclusion: AV and VV delay optimized BV pacing acutely improve ICG CO and ACI and their NYHA class during long-term follow-up. ICG may be a simple and useful technique to optimize AV and VV delay in CRT.
Introduction: Cardiac resynchronisation therapy (CRT) with atrioventricular (AV) and interventricular (VV) optimized biventricular pacing (BV) is an established therapy for heart failure (HF) patients. The aim of the study was to compare AV and VV delay optimization with cardiac output (CO), cardiac index (CI), contractility index (IC) and acceleration index (ACI) impedance cardiographic (ICG) methods in CRT.
Methods: 15 HF patients (age 66 ± 10 years; 2 females, 13 males) in New York Heart Association (NYHA) class 3.1 ± 0.4, left ventricular (LV) ejection fraction 21.3 ± 7.8 % and QRS duration 176.1 ± 31.7 ms underwent AV and VV delay optimization with CO, CI, IC and ACI (Cardioscreen ®, Medis GmbH, Ilmenau, Germany) at different AV and VV delay BV pacing settings versus right ventricular (RV) pacing one day after implantation of a CRT device.
Results: Optimal AV delay after atrial sensing was 108.6 ± 20.3 ms (n=14) and optimal AV delay after atrial pacing 190 ± 14.1 ms (n=2) with AV delay range from 80 ms to 200 ms. Optimal VV delay was -12.3 ± 25.9 ms left ventricular before RV pacing. RV versus BV pacing mode resulted in improvement of CO from 3.4 ± 1.2 l/min to 4.4 ± 1.4 l/min (p<0.001), CI from 1.8 ± 0.64 l/min/m² to 2.4 ± 0.78 l/min/m² (p<0.001), IC from 0.028 ± 0.011 1/s to 0.036 ± 0.013 1/s (p<0.001) and ACI from 0.667 ± 0.227 1/s² to 0.834 ± 0.282 1/s² (p<0.002). During 34 ± 26 month BV pacing, the NYHA class improved from 3.1 ± 0.4 to 2.1 ± 0.4 (p<0.001).
Conclusion: AV and VV delay optimized BV pacing acutely improve hemodynamic parameters of transthoracic ICG and their NYHA class during long-term follow-up. ICG may be a simple and useful technique to optimize AV and VV delay in CRT.
Introduction: Cardiac resynchronization therapy (CRT) with biventricular (BV) pacing is an established therapy for heart failure (HF) patients with ventricular desynchronization and reduced left ventricular (LV) ejection fraction. The aim of this study was to evaluate electrical ventricular desynchronization with transthoracic and transesophageal signal averaging electrocardiography in HF, to better select patients for CRT.
Methods: 13 HF patients (age 68 ± 10 years; 2 females, 11 males) with New York Heart Association (NYHA) class 2.8 ± 0.5, 28.6 ± 12.6 % LV ejection fraction and 155 ± 24 ms QRS duration (QRSD) were analysed with transthoracic and transesophageal electrocardiogram recording and novel National Intruments LabView 2009 signal averaging software. Esophageal TO Osypka catheter was perorally applied to the esophagus and placed in the position of maximum LV de-flection. The 0.05-Hz high-pass filtered surface electrocardiogram and the 10-Hz high-pass filtered bipolar transesophageal electrocardiogram were recorded with Bard EP-System and 1000-Hz sampling rate.
Results: Transesophageal LV electrogram recording was possible in all HF patients (n=13). Transesophageal interventricular conduction delay (IVCD) was 51 ± 19 ms and measured between the earliest onset of QRS in the 12-channel surface electrocardiogram and the onset of the LV deflection in the transesophageal electrocardiogram. Transesophageal intra-left ventricular delay (LVCD) was 90 ± 16 ms and measured between the onset and offset of the LV deflection in the transesophageal electrocardiogram. QRSD to transesophageal IVCD ratio was 3.43 ± 1.31 ms, QRSD to transesophageal LVCD ratio was 1.75 ± 0.28 ms and QRSD was evaluated between onset and offset of QRS signal in the 12-channel surface electrocardiogram.
Conclusion: Determination of IVCD, LVCD, QRSD-to-IVCD-ratio and QRSD-to-LVCD-ratio by transesophageal LV electrogram recording with LabView 2009 signal averaging technique may be useful parameters of ventricular desynchronisation to improve patient selection for CRT.
Using guideline parameters for indication of cardiac resynchronization therapy (CRT), only about two thirds of the patients improve clinically. Unfortunately both, surface ECG and echo are uncertain to predict CRT response. To better characterize cardiac desynchronization in heart failure, interventricular (IVCD) and intra-leftventricular conduction delays (ILVCD) were measured by esophageal left ventricular electrogram (LVE). Recordings in 43 CRT patients (34m, 9f, age: 64.7 ± 9.5yrs) evidenced only weak correlation between IVCD and QRS of 0.53 and between ILVCD and QRS of 0.33. This demonstrated that QRS duration is not a reliable indicator of desynchronization. Therefore, the study resulted into development of LVE feature for a programmer with implant support device. It can be used interoperatively to guide the left ventricular electrode location in order to increase responder rate in CRT.
In
this paper, a new method is demonstrated for onlin
e remote simulation of photovo
ltaic systems. The required
communication technology for the data exchange is introduced a
nd the methods of PV generato
r parameter extraction for the
simulation models are analysed. The method
shown for parameter extraction from the ma
nufacturer data is especially useful
for the commissioning procedure, where the measured installed pow
er is transferred to standard test conditions using the
simulation model and can then be easily compared with the de
sign power. At a simulation accuracy of 2% using the software
environment INSEL
®
any problems with the PV gene
rator can reliably be detected.
Online simulation of a grid connected PV generator is then
carried out during the operation of the photovoltaic plant. The
visualisation includes both the monitored and
the simulated online data sets, so that a very efficient fault detection scheme i
s
available. The method is implemented and
validated on several grid connected photovolta
ic power plants in Germany. It is
excellently suited to provide automatic and real time fault
detection and significantly impr
ove the commissioning procedure
for photovoltaic plants of all sizes.
RFID- Frontend ISO 15693
(2008)
The aim of the paper was to investigate the energy saved in the shift from separate generation of thermal and electrical energy to trigeneration at the energy facility in Offenburg University of Applied Sciences (HS OG). The energy facility at HS OG used a traditional heating system and electricity from grid until 2007 afterwhich they installed a trigeneration system to meet its continuously changing dynamic thermal and electrical demands. This paper highlights the methodology that had been derived to analyze and study the effect of this shift based on the energy consumption data available from 2004 to 2011, which were scarce due to the limited monitoring. From the energy analysis, we concluded that 8 % primary energy was saved in this shift at the energy facility of HS OG. And from economical perspective 5 % useful thermal energy and 39 % useful electrical energy was saved in this shift at the energy facility of HS OG. Nevertheless, the term energy saving, in general, is very relative and complex to define in such a changeover.
Particle and Gaseous Emissions of Diesel Engines Fuelled by Different Non-Esterified Plant Oils
(2007)
The particulate matter and gas emissions of several plant oils are analyzed in the hot exhaust gas under various engine conditions at different speeds and loads The measurement data are compared to the emission values of conventional diesel fuel (gas oil). The investigation concentrates on a modern common rail TDI light duty diesel, four cylinders, for passenger cars. The differences in the gas and particulate matter emission - compared to conventional diesel fuel - are remarkably low for the diesel engine which is properly adjusted for the plant oils. Emission data of an old heavy duty diesel engine are also shown for comparison reasons and reveals large differences. Differences are found in the pressures of the indicator diagram, time resolved over the crank angle. Plant oils consistently exhibit a higher cylinder pressure. The TEM investigation confirms the differences found by the LPME (long path multi-wavelength extinction) on-line analysis.
About 20% of those heart failure patients receiving cardiac resynchronization therapy (CRT) are in atrial fibrillation (AF). Current guidelines apply for patients in sinus rhythm only. Recent studies have shown again, that successful resynchronization is closely linked to a pre-existent ventricular desynchronization. In those studies, the interventricular conduction delay (IVCD) was determined prior to device implantation by ultrasound in patients with sinus rhythm (SR)only. In patients with AF this method ́s use is limited.
To implement left-heart electrogram (LHE) into standard programmers and to simplify IVCD measurement in heart failure patients with AF, LHE was recorded in 11 AF patients with heart failure by Biotronik ICS3000 programmer via a15Hz Butterworth high-pass filter. Therefore, TOslim esophageal electrode (Dr. Osypka GmbH, Rheinfelden, Germany) was perorally applied and fixed in position of maximal left ventricular defection. IVCD was measured between onset of QRS in surface ECG and left ventricular defection (LV) in LHE. In addition, intra-left ventricular conduction delay (ILVCD) was measured as duration of LV in LHE.
In all of the 11 AF patients, desynchronization was quantifiable by LHE. Mean QRS of 162 ± 27ms (120-206ms) was linked with IVCD of 62ms ± 27ms (37-98ms) and ILVCD of 110 ± 20ms (80-144ms), at mean. Correlation between IVCD and QRS was 0.39 (n. s.) with IVCD/QRS ratio of 0.38 ± 0.11 (0.22-0.81).
A 15Hz high-pass filtered LHE feature of the Biotronik ICS3000 programmer is feasible to quantify ventricular dyssynchrony in heart failure patients with AF in order to clearly indicate implantation of CRT systems. As relations between QRS duration, IVCD and ILVCD considerably differ interindividually, the predictive values of IVCD, ILVCD and IVCD/QRS ratio for individual CRT response or non-response shall be identified in follow-up studies.
In the brain-cell microenvironment, diffusion plays an important role: apart from delivering glucose and oxygen from the vascular system to brain cells, it also moves informational substances between cells. The brain is an extremely complex structure of interwoven, intercommunicating cells, but recent theoretical and experimental works showed that the classical laws of diffusion, cast in the framework of porous media theory, can deliver an accurate quantitative description of the way molecules are transported through this tissue. The mathematical modeling and the numerical simulations are successfully applied in the investigation of diffusion processes in tissues, replacing the costly laboratory investigations. Nevertheless, modeling must rely on highly accurate information regarding the main parameters (tortuosity, volume fraction) which characterize the tissue, obtained by structural and functional imaging. The usual techniques to measure the diffusion mechanism in brain tissue are the radiotracer method, the real time iontophoretic method and integrative optical imaging using fluorescence microscopy. A promising technique for obtaining the values for characteristic parameters of the transport equation is the direct optical investigation using optical fibers. The analysis of these parameters also reveals how the local geometry of the brain changes with time or under pathological conditions. This paper presents a set of computations concerning the mass transport inside the brain tissue, for different types of cells. By measuring the time evolution of the concentration profile of an injected substance and using suitable fitting procedures, the main parameters characterizing the tissue can be determined. This type of analysis could be an important tool in understanding the functional mechanisms of effective drug delivery in complex structures such as the brain tissue. It also offers possibilities to realize optical imaging methods for in vitro and in vivo measurements using optical fibers. The model also may help in radiotracer biomarker models for the understanding of the mechanism of action of new chemical entities.