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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.
Introduction: Cardiac resynchronization therapy (CRT) with biventricular (BV) pacing is an established therapy for heart failure (HF) patients with ventricular desynchronisation and reduced left ventricular (LV) function. The aim of this study was to evaluate preejection period (PEP) and left ventricular ejection time (LVET) with transthoracic signal averaging impedance and electrocardiography in HF patients with and without BV pacing.
Methods: 10 HF patients (age 68.9 ± 8 years; 2 females, 9 males) with New York Heart Association (NYHA) class 2,9 ± 0.5, 30.9 ± 10.5 % LV ejection fraction and 159.4 ± 22.9 ms QRS duration were analysed with transthoracic impedance and electrocardiography (Cardioscreen Medis, Ilmenau, Germany) and novel National Intruments LabView 2009 signal averaging software. One day after BV pacing device implantation, AV and VV delays were optimized by transthoracic impedance cardiography and stroke volume (SV) and cardiac output (CO) were gained by Cardioscreen.
Results: Transthoracic impedance and electrocardiography AV and VV delay opimization was possible in all HF patients with BV pacing devices (n= 10). PEP was 154 ± 24ms without BV pacing and measured between onset of QRS in the surface electrocardiogram and onset of ventricular deflection in the impedance cardiogram. LVET was 342 ± 65ms without BV pacing and measured between onset and offset of ventricular deflection in the impedance cardiogram. The use of optimal AV and VV delay BV pacing resulted in improvement of SV from 64.1 ± 26.5 ml to 94.1 ± 33.96 ml (P < 0.05) and CO from 4.05 ± 1.36 l/min to 6.44 ± 1.56 l/min (P < 0.05).
Conclusion: PEP and LVET may be useful parameters of ventricular Desynchronisation. AV and VV delay optimized BV pacing improve SV and CO. Impedance and electrocardiography with LabView 2009 signal averaging may be a simple and useful technique to optimize CRT.
BiCI users’ sensitivity to interaural phase differences for single- and multi-channel stimulation
(2016)
Das normalhörende auditorische System ist in der Lage, interaurale Zeit- bzw. Phasendifferenzen zur verbesserten Signaldetektion im Störgeräusch zu nutzen. Dieses Phänomen wird häufig als binaurale Entmaskierung bezeichnet und ist sowohl bei einfachen Signalen wie Sinustönen, als auch bei Sprachsignalen im Störgeräusch wirksam. Vorangegangene Studien haben gezeigt, dass binaurale Entmaskierung eingeschränkt auch bei bilateralen CI-Trägern beobachtbar ist (Zirn et al., 2016).
Aktuelle Ergebnisse zeigen, dass die binaurale Entmaskierung sensitiv gegenüber der bilateralen CI-Anpassung ist. So lässt sich der Effekt durch tonotopen Abgleich und Herausstellen eines apikalen Feinstrukturkanals modulieren. Steigerungen der binauralen Entmaskierung um bis zu 1,5 dB sind auf diese Weise gegenüber der konventionellen CI-Anpassung möglich. Allerdings variiert der Einfluss der CI-Anpassung interindividuell erheblich.
Introduction: To simplify AV delay (AVD) optimization in cardiac resynchronization therapy (CRT), we reported that the hemodynamically optimal AVD for VDD and DDD mode CRT pacing can be approximated by individually measuring implant-related interatrial conduction intervals (IACT) in oesophageal electrogram (LAE) and adding about 50ms. The programmer-based St Jude QuickOpt algorithm is utilizing this finding. By automatically measuring IACT in VDD operation, it predicts the sensed AVD by adding either 30ms or 60ms. Paced AVD is strictly 50ms longer than sensed AVD. As consequence of those variations, several studies identified distinct inaccuracies of QuickOpt. Therefore, we aimed to seek for better approaches to automate AVD optimization.
Methods: In a study of 35 heart failure patients (27m, 8f, age: 67±8y) with Insync III Marquis CRT-D systems we recorded telemetric electrograms between left ventricular electrode and superior vena cava shock coil (LVtip/SVC = LVCE) simultaneously with LAE. By LVCE we measured intervals As-Pe in VDD and Ap-Pe in DDD operation between right atrial sense-event (As) or atrial stimulus (Ap), resp., and end of the atrial activity (Pe). As-Pe and Ap-Pe were compared with As-LA an Ap-LA in LAE, respectively.
Results: End of the left atrial activity in LVCE could clearly be recognized in 35/35 patients in VDD and 29/35 patients in DDD operation. We found mean intervals As-LA of 40.2±24.5ms and Ap-LA of 124.3±20.6ms. As-Pe was 94.8±24.1ms and Ap-Pe was 181.1±17.8ms. Analyzing the sums of As-LA + 50ms with duration of As-Pe and Ap-LA + 50ms with duration of Ap-Pe, the differences were 4.7±9.2ms and 4.2±8.6ms, resp., only. Thus, hemodynamically optimal timing of the ventricular stimulus can be triggered by automatically detecting Pe in LVCE.
Conclusion: Based on minimal deviations between LAE and LVCE approach, we proposed companies to utilize the LVCE in order to automate individual AVD optimization in CRT pacing.