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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.
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.
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.
Electrical velocimetry to optimize VV delay in biventricular VVIR and DDD pacing for heart failure
(2011)
Introduction: VV delay (VVD) is the only parameter to hemodynamically optimize cardiac resynchronization therapy (CRT) for patients with atrial fibrillation (AF). Electrical velocimetry (EV) has been established to monitor thoracic electrical conductivity and to calculate hemodynamic surrogate parameters. We compared the response of this method to hemodynamic parameter changes between CRT patients with sinus rhythm (SR) and patients with AF.
Methods: VVD was individualized in 17 CRT patients in SR (12m, 5f, 67.0±7.2yrs.) after echo AV delay optimization and in 11 CRT patients in AF (10m, 1f, 69.8±9.6yrs.) using the Aesculon Cardiovascular Monitor (Osypka Medical, Berlin, Germany). Serial 30s EV recordings were accomplished, decreasing the VVD stepwise by 10ms from +60ms to -60ms between right and left ventricular stimulus. Optimal VVD was determined by the maximum of at least two of the three averaged parameters stroke volume (SV), cardiac output (CO) and cardiac index (CI). The response of SV, CO and CI was tested comparing their values in optimal VVD and suboptimal VVD. Suboptimal VVD was defined by optimal VVD±20ms.
Results: In all 28 patients in SR and AF, EV recordings resulted in optimal VVD. Between suboptimal and optimal mean VVD of 18.6±30.8ms between left and right ventricular stimulus, SV increased by 7.2±6.8%, CO by 7.8±7.2% and CI by 10.0±13.3% (all p<0.02). In the SR group with VVD of 18.8± 29.6ms, SV increased by 4.6±2.9%, CO by 5.0±2.9% and CI by 4.9±2.9% (all p<0.02). In the AF group with VVD of 18.2±4.0ms, SV increased by 10.4±8.9%, CO by 11.3±9.5% and CI by 16.4±18.2% (all p<0.02). Significant differences were not found between optimal VVD in SR and AF patients.
Conclusion: EV is a feasible serial method to individualize VVD in DDD and VVIR pacing for heart failure. Its response to hemodynamic changes demonstrates the value of EV for VVD fine-tuning.
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.
In-vivo and in-vitro comparison of implant-based CRT optimization - What provide new algorithms?
(2011)
Introduction: In cardiac resynchronization therapy (CRT), individual AV delay (AVD) optimization can effectively increase hemodynamics and reduce non-responder rate. Accurate, automatic and easily comprehensible algorithms for the follow-up are desirable. QuickOpt is the first attempt of a semi-automatic intracardiac electrogram (IEGM) based AVD algorithm. We aimed to compare its accuracy and usefulness by in-vitro and in-vivo studies.
Methods: Using the programmable ARSI-4 four-chamber heart rhythm and IEGM simulator (HKP, Germany), the QuickOpt feature of an Epic HF system (St. Jude, USA) was tested in-vitro by simulated atrial IEGM amplitudes between 0.3 and 3.5mV during both, manual and automatic atrial sensing between 0.2 and 1.0mV. Subsequently, in 21 heart failure patients with implanted biventricular defibrillators, QuickOpt was performed in-vivo. Results of the algorithm for VDD and DDD stimulation were compared with echo AV delay optimization.
Results: In-vitro simulations demonstrated a QuickOpt measuring accuracy of ± 8ms. Depending on atrial IEGM amplitude, the algorithm proposed optimal AVD between 90 and 150ms for VDD and between 140 and 200ms for DDD operation, respectively. In-vivo, QuickOpt difference between individual AVD in DDD and VDD mode was either 50ms (20pts) or 40ms (1pt). QuickOpt and echo AVD differed by 41 ± 25ms (7 – 90ms) in VDD and by 18 ± 24ms (17-50ms) in DDD operation. Individual echo AVD difference between both modes was 73 ± 20ms (30-100ms).
Conclusion: The study demonstrates the value of in-vitro studies. It predicted QuickOpt deficiencies regarding IEGM amplitude dependent AVD proposals constrained to fixed individual differences between DDD and VDD mode. Consequently, in-vivo, the algorithm provided AVD of predominantly longer duration than echo in both modes. Accepting echo individualization as gold standard, QuickOpt should not be used alone to optimize AVD in CRT patients.
Die kardiale Resynchronisationstherapie ist ein großer Segen für viele Patienten mit einer Herzschwäche, die auf einen krankhaften Verlust der synchronen Kontraktion beider Herzkammern zurückzuführen ist. Warum einige von ihnen jedoch nicht darauf ansprechen, wird gegenwärtig erforscht. Als eine neue Methode mit dem Ziel der Effektivitätssteigerung dieser Therapie mit elektronischen Implantaten demonstrieren wir die Nutzbarkeit von durch eine Schluckelektrode aus der Speiseröhre abgeleiteten Elektrokardiogrammen.
Introduction: Patient selection for cardiac resynchronization therapy (CRT) requires quantification of left ventricular conduction delay (LVCD). After implantation of biventricular pacing systems, individual AV delay (AVD) programming is essential to ensure hemodynamic response. To exclude adverse effects, AVD should exceed individual implant-related interatrial conduction times (IACT). As result of a pilot study, we proposed the development of a programmer-based transoesophageal left heart electrogram (LHE) recording to simplify both, LVCD and IACT measurement. This feature was implemented into the Biotronik ICS3000 programmer simultaneously with 3-channel surface ECG.
Methods: A 5F oesophageal electrode was perorally applied in 44 heart failure CRT-D patients (34m, 10f, 65±8 yrs., QRS=162±21ms). In position of maximum left ventricular deflection, oesophageal LVCD was measured between onsets of QRS in surface ECG and oesophageal left ventricular deflection. Then, in position of maximum left atrial deflection (LA), IACT in VDD operation (As-LA) was calculated by difference between programmed AV delay and the measured interval from onset of left atrial deflection to ventricular stimulus in the oesophageal electrogram. IACT in DDD operation (Ap-LA) was measured between atrial stimulus and LA..
Results: LVCD of the CRT patients was characterized by a minimum of 47ms with mean of 69±23ms. As-LA and Ap-LA were found to be 41±23ms and 125±25ms, resp., at mean. In 7 patients (15,9%), IACT measurement in DDD operation uncovered adverse AVD if left in factory settings. In this cases, Ap-LA exceeded the factory AVD. In 6 patients (13,6%), IACT in VDD operation was less than or equal 10ms indicating the need for short AVD.
Conclusion: Response to CRT requires distinct LVCD and AVD optimization. The ICS3000 oesophageal LHE feature can be utilized to measure LVCD in order to justify selection for CRT. IACT measurement simplifies AV delay optimization in patients with CRT systems irrespective of their make and model.