Neue Technologien zur Optimierung in der CRT-Programmierung

After implanting a CRT device, consistent and scheduled patient follow-up is mandatory. Besides determining electrode parameters and reviewing arrhythmic episodes, these follow-ups focus on monitoring and optimizing congestive heart failure therapy. Therefore new CRT devices present methods for heart failure surveillance and telemetric transmission of the acquired data, which allows the physician to respond immediately to the varying needs of the respective heart failure patient. In addition to cardiac resynchronization, optimization of atrioventricular (AV) and interventricular (VV) delay provide major hemodynamic benefits. As echocardiographic optimization of AV and VV delay is time consuming it is often not feasible during daily clinical practice. Therefore implemented algorithms that automatically determine and adapt AV and VV delays with respect to the fluctuating needs of the patients are essential. This article presents the current state of monitoring and optimization methods in CRT devices.     

心脏再同步治疗起搏参数优化对血流动力学的影响及随访

目的应用超声心动图观察心脏再同步治疗（CRT）后不同时期AV、VV间期优化对心力衰竭血流动力学的影响,探讨AV、VV间期优化在增强CRT临床疗效中的作用。方法扩张性心肌病心力衰竭患者32例接受CRT治疗,并于植入术后7d,3、6个月在超声心动图指导下进行AV、VV间期优化,观察优化后不同时间起搏参数、血流动力学指标。结果32例入选患者均一次成功植入三腔起搏器,术后1、3、6个月随访起搏阈值、感知、阻抗的改变差异无统计学意义（P〉0．05）。CRT植入术后7d,87％（28／32）、90％（29／32）患者分别需要AV、VV间期优化,植入术后6个月仍有18％（6／32）、16％（5／32）患者分别再次需要AV、VV间期优化。植入术后7d、3个月优化起搏与术后未优化相比,舒张期充盈时间（DFT）延长、Tei指数下降（P〈0．05）。植入术后6个月优化起搏与植入术后即刻相比DFT延长、主动脉瓣前向血流速度时间积分（V11）增加、Tei指数下降、E／Em比值下降、左心室射血分数（LVEF）明显增加（P〈0．05）。结论CRT植入术后AV、VV间期优化改善心力衰竭患者的血流动力学,可以带来良好的临床疗效。     

Optimierte CRT-Programmierung

Cardiac resynchronization therapy (CRT) can result in significant clinical improvement in patients with congestive heart failure. Non-response to CRT might be attributable to suboptimal programming. Follow-up has to ensure effective left ventricular (LV) stimulation at rest and also sufficient exercise-dependent atrial rates. Rate adaptive pacing is required in case of chronotropic incompetence. Specific algorithms may help to restore biventricular pacing or the enhance biventricular pacing rate when intrinsic AV conduction occurs, e.g., during intermittent atrial fibrillation. An individual adaptation of the AV interval is essential to achieve maximal benefit from resynchronization. Optimized AV interval programming synchronizes atrial and ventricular contraction, maximizing the atrial contribution to LV diastolic filling and preventing presystolic mitral regurgitation. Interventricular synchrony and LV contraction might be further harmonized by VV interval adaptation, although the impact of VV optimization on CRT outcome is still under debate. Non-invasive methods of AV and VV interval optimization by electro- and echocardiography are discussed.     

Optimizing cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) improves clinical outcome and survival in advanced heart failure. However, some patients do not respond clinically or show improvement in left ventricular function. Our focus has turned to why such “nonresponders” exist. Follow-up of CRT has led to several explanations, varying by individual patient, and has shown the importance of device programming in CRT in heart failure. The failing heart displays delayed contraction in the ventricle, also referred to as mechanical dyssynchrony. Simply pacing both ventricles simultaneously might not be adequate to optimize systolic function. Individually tailoring the atrioventricular (AV) timing can improve left ventricular filling and cardiac output, and adjusting the interventricular (VV) pacing delay has also been shown to improve hemodynamics. Increasing evidence regarding AV and VV optimization is emerging. This article reviews the current data on optimization, including the physiology, numerous approaches, and current issues.     

Optimization of pacing intervals in cardiac resynchronization therapy

In patients with heart failure, left ventricular systolic dysfunction and prolonged QRS complex, cardiac resynchronization therapy (CRT) is a treatment method aimed at restoration of myocardial depolarization synchronicity. However, the extent of clinical and echocardiographic improvement depends on anatomical relations in individual patients, on structural changes in the heart, on intrinsic electrical activation, and on the position of pacing leads. Many parameters of CRT devices may be changed in order to tailor the function of CRT to the needs of a particular patient; the most important among them is AV and VV interval. The largest trials studying CRT used various methods for optimization of these intervals but unequivocal proof of the benefit brought by optimization is still lacking. Many methods were evaluated, most frequently based on echocardiography and intracardiac electrogram interval measurement. However, drawbacks in statistics make the studies of limited value for establishing a reference method or guidance for daily practice. Echocardiography has inherent variability of results and is highly operator dependent. Optimization based on intracardiac electrogram intervals has not proved yet to be of clear benefit above arbitrary AV interval. The most promising method is hemodynamic assessment by finger plethysmography. Measured data are highly reproducible and operator-independentA randomized multicenter double-blind study using finger plethysmography is needed to prove the value of this method and of CRT optimization in general. The measurement of information content in any data suitable for CRT optimization, analysis of reproducibility and general usage of confidence intervals may show other methods appropriate for it, too. The cooperation with a statistician is oftentimes a necessity.     

超声心动图引导下心脏再同步化治疗的优化调节

目的 应用超声心动图技术优化调节心脏再同步化治疗(CRT)的疗效.方法 接受CRT的慢性心力衰竭患者30例,在超声心动图引导下进行优化AV间期和VV间期.结果 30例患者CRT优化后心功能得到改善,左室充盈时间较优化前增加,二尖瓣返流减少;左室内各室壁收缩期达峰时间标准差减少,左室流出道速度时间积分上升,左室收缩末容积减少.结论 超声引导下AV间期和VV间期优化能够提高CRT临床疗效.     

Impedance cardiography: a useful and reliable tool in optimization of cardiac resynchronization devices.

AIMS: Optimizing cardiac resynchronization therapy (CRT) devices has become more complex since modification of both atrioventricular (AV) and interventricular (VV) stimulation intervals has become possible. The current paper presents data from the routine use of impedance cardiography (IC)-based cardiac output (CO) measurements to guide the optimization of AV- and VV-interval timing of CRT devices. METHODS AND RESULTS: Forty-six patients with heart failure (left ventricular ejection fraction <35%, New York Heart Association (NYHA) III-IV) and left bundle branch block (>130 ms) in sinus rhythm were evaluated 3-5 days after implantation of a CRT device by means of IC. CO was measured without pacing and with biventricular pacing using a standard protocol of VV- and AV-interval modification from -60 to +60 ms and 80 to 140 ms, respectively, in 20 ms steps. Mean CO without pacing was 3.66 +/- 0.85 L/min and significantly increased to 4.40 +/- 1.1 L/min (P<0.05) with simultaneous biventricular pacing and an AV interval of 120 ms. 'Optimizing' both VV and AV intervals further increased CO to 4.86 +/- 1.1 L/min (P<0.05). Maximum CO was measured in most patients with left ventricular pre-excitation. The proportion of 'non-responders' to CRT was reduced by 56% following AV- and VV-interval modification using IC guidance. CONCLUSION: Modification of both AV and VV intervals in patients with a CRT device significantly improves CO compared with standard simultaneous biventricular pacing and no pacing. IC is a useful non-invasive technique for guiding this modification. Marked variability of optimal AV and VV intervals between patients requires optimization of these intervals for each patient individually.     

Cardiac resynchronization therapy: variations in echo-guided optimized atrioventricular and interventricular delays during follow-up

BACKGROUND: Relatively few data are available on long-term echocardiographic optimization of atrioventricular (AV) and interventricular (VV) delay programming in cardiac resynchronization therapy (CRT). We assessed variations in optimized AV and VV delays during long-term follow-up. METHODS: Thirty-seven consecutive heart failure patients received Doppler echocardiographic optimization of AV and VV delay within 48 hours from CRT device implantation, at 6 months and at 12 months (the last for the first enrolled 14 patients). RESULTS: After implantation, median optimized AV delay was 100 ms (range, 45 ms); VV optimization led to simultaneous biventricular activation in 4 patients, left ventricular preactivation in 17 patients and right ventricular preactivation in 16 patients. At 12 months median AV delay decreased to 85 ms (23 ms) (P < 0.05 vs. baseline). With respect to previous assessment, VV delay variations > or =40 ms were observed in 41% of the patients at 6 months and in 57% of the tested patients at 12 months. A nonconcordance (by Kappa test) of optimized VV delays was found between each new assessment and the previous one. VV delay optimization was associated with significant (P < 0.001) increases in aortic velocity time integral both at baseline and during follow-up. CONCLUSIONS: Echocardiographic optimization of AV and VV delay is associated with broad intraindividual variability during follow-up. A new assessment of optimized VV delays during long-term follow-up reveals a nonconcordance with previous values and provides increases in forward stroke volume.     

Comparison of different approaches for optimization of atrioventricular and interventricular delay in biventricular pacing

Aims: It has been shown that optimizing atrioventricular (AV) andinterventricular (VV) delay improves cardiac performance inpatients with biventricular pacemakers. However, there is nostandard method for optimization available yet. The aim of thisstudy was to compare echocardiographic parameters—displacementimaging, A wave duration, and aortic velocity time integral(VTI)—and acoustic cardiography derived electromechanicalactivation time (EMAT) using different approaches of AV andVV delay optimization. We tested whether the initial optimizationof the AV interval followed by VV optimization at that optimalAV interval or initial optimization of the VV interval followedby AV optimization at the determined optimal VV interval wasaccurate and consistent, and how this compared to testing everyconceivable combination of AV and VV intervals available. Methods and results: A group of 20 patients with biventricular pacemakers was included.Displacement imaging, A wave duration, and aortic VTI were determinedat different combinations of AV (100, 150, 200, 250 ms) andVV (RV40, 0, LV40 ms) intervals. If AV duration was determinedfirst, displacement imaging identified the best setting in 8/20,aortic VTI in 10/20, A duration in 13/20, and EMAT in 18/20patients. With VV duration determined first, the best settingwas more difficult to identify regardless of the method used.There was a poor agreement in optimal AV and VV delays of thedifferent methods, and there was no single patient in whom allfour methods yielded the same delay combination. Conclusion: It is advisable to measure a full grid of AV and VV delays toidentify optimal settings rather than optimizing one of thetwo delays first. Different techniques for delay optimizationresulted in different optimal delay combinations.     

Should We Optimize Cardiac Resynchronization Therapy During Exercise?

Should We Optimize CRT During Exercise? Cardiac resynchronization therapy aims at diminishing cardiac dyssynchrony in patients with heart failure. The effect of cardiac resynchronization therapy can be improved by optimization of the atrioventricular (AV) and interventricular (VV) delays. Currently, optimization of these pacing settings is mainly performed during resting conditions. This paper aims to objectively review the current literature about a rate‐adaptive AV and VV delay in cardiac resynchronization therapy. The current evidence for a rate‐adaptive AV and VV delay comprises only small nonrandomized studies on acute effects. The effect of exercise on the optimal AV delay was heterogeneous between studies. The optimal VV delay was influenced by exercise conditions in some, but not all patients. Possible explanations lie in the heterogeneous electrical and mechanical responses to exercise in patients with a complex disease such as heart failure with asynchronous contraction. Current evidence is insufficient to show the superiority of a rate‐adaptive AV or VV delay in all CRT patients. Individualized exercise programming may be warranted in selected patients. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1307‐1316, November 2010)     

Improved response to cardiac resynchronization therapy through optimization of atrioventricular and interventricular delays using acoustic cardiography: a pilot study

BackgroundThe purpose of this pilot study was to determine the utility of acoustic cardiography for the optimization of atrioventricular (AV) and interventricular (VV) delays in cardiac resynchronization therapy (CRT).Methods and ResultsWe evaluated 14 patients (86% male, mean age 64 ± 9 years, mean time since implant 15 ± 18 months). Subjects were enrolled >10 weeks after CRT implant. Spiroergometry and 2-dimensional/3-dimensional echocardiography were used to assess cardiac performance for “out-of-the-box” settings (baseline settings: AV 120 ms, VV 0 ms) versus optimal settings (determined by acoustic cardiography). Cardiac performance measurements were performed 6 weeks after settings were modified. Optimal AV/VV settings were determined based on the lowest electromechanical activation time (EMAT, the time from the onset of QRS to the mitral valve component of the first heart sound). Statistical analysis was performed using a paired 2-tailed Student's t-test. In comparison to “out-of-the-box” settings, AV/VV delay optimization with acoustic cardiography improved cardiac performance as indicated by significant changes in work capacity, maximum oxygen uptake, oxygen pulse, ejection fraction, end-systolic volume, and velocity-time integral in left ventricular outflow tract.ConclusionsAV and VV optimization by acoustic cardiography produces significant improvements in objective clinical and hemodynamic parameters in comparison to typical “out-of-the-box” settings.     

Shortening of paced QRS duration after electrocardiographic optimization of left ventricular pacing vector in patients treated with Cardiac Resynchronization Therapy

Background

Choice of left ventricular pacing vector (LVPV) affects the QRS-duration (QRSd) in patients with Cardiac Resynchronization Therapy (CRT). It is not known whether testing all LVPVs reduces QRSd compared to device-based “standard-programming”.

动态优化AV/VV间期心脏再同步治疗慢性心力衰竭的临床观察

目的: 观察动态优化AV/VV间期心脏再同步治疗（cardiac resynchronization therapy,CRT）治疗慢性心力衰竭（CHF）的短中期疗效。方法: 12例CHF晚期患者接受CRT治疗,分别于植入前、植入术后3、6个月在超声心动图指导下优化房室（AV）间期和室室（VV）间期,同时观察心腔结构、二尖瓣返流及心电图、脑钠尿肽（BNP）检查等,评价CRT临床疗效。结果: 最佳优化AV间期120～180（158±19）ms和VV间期4～28（16±7）ms,临床症状改善,六分钟步行距离由(257±23)m增加至(344±21)m,QRS时限由（136±17）ms降至(109±12)ms(P<0.01,P<0.05)。植入后左室舒张末内径（LVEDD）较植入前明显缩小［(71±10) mm vs. (54±4),P<0.05］; 左室射血分数（LVEF）提高［(0.308±0.022) vs. (0.531±0.085),P<0.01］;血浆BNP值由植入前（876±415）ng/L降至(70±28)ng/L(P<0.05)。结论: 动态程控AV/VV间期可以提高CRT对CHF患者短、中期疗效。     

Discordant Left and Right Ventricular Optimal Atrioventricular and Interventricular Delays during Biventricular Pacemaker Optimization

Echocardiography‐guided optimization of atrioventricular (AV) delay (AVD) improves left ventricular (LV) filling, and optimized interventricular delay (VVD) leads to further improvement in cardiac output in patients with biventricular (Biv) pacing. Investigators use LV filling and ejection to optimize AV and VV delay in patients with Biv pacing. Effect of such optimization on right‐sided hemodynamics remains unknown. In our experience, few patients experience worsening of right ventricle (RV) hemodynamics when LV parameters are optimized. We present a series of cases where we observed suboptimal RV filling or ejection at optimal AVD and VVD for LV. This RV‐LV discordance may contribute to nonresponder rate to cardiac resynchronization therapy (CRT) and should be evaluated in a consecutive series of CRT nonresponder patients to help improve CRT response.     

提高CRT患者疗效的机理和方法

心脏再同步化治疗(CRT)是治疗顽固性心力衰竭的有效手段。通过运用以组织多普勒为基础的超声技术,合理评价心脏机械不同步收缩,选择合适的患者,并指导选择左室电极理想的起搏位置、设置最佳房室间期及室间间期,是目前实现提高CRT疗效的主要方法。但还需要更多的以临床事件为终点的数据以证实这些观点。应用新的超声方法,以心脏电标测方法指导电极放置,以腔内电图的方法优化参数设置可能有助于进一步提高CRT的疗效。     

Optimal use of echocardiography in cardiac resynchronisation therapy

Echocardiography has several roles in patients with cardiac resynchronisation therapy (CRT). First, it can optimise selection of CRT candidates by demonstration of left ventricular (LV) dyssynchrony. Second, it can be used to assess immediate response to CRT, including detection of acute LV resynchronisation. Echocardiography is also useful to evaluate long-term benefit from CRT. Finally, echocardiography is important in optimisation of pacemaker settings, including AV and VV optimisation.     

Electrocardiographic versus echocardiographic optimization of the interventricular pacing delay in patients undergoing cardiac resynchronization therapy

Electrocardiographic VV Optimization. Introduction: Echocardiographic optimization of the VV interval may improve CRT response, but it is time‐consuming and not routinely performed. The aim of this study was to compare the response to cardiac resynchronization therapy (CRT) when the interventricular pacing (VV) interval was optimized by Tissue Doppler Imaging (TDI) to CRT response when it was optimized following QRS width criteria. Methods and Results: The study included 156 consecutive CRT patients with severe heart failure and left bundle‐branch block configuration. Atrioventricular interval was selected according to a pulsed Doppler assessment, and VV optimization was randomly assigned to echocardiography (ECHO group, n = 78) or electrocardiography (ECG group, n = 78). Optimal VV was defined for the ECHO group as producing the best LV intraventricular synchrony according to TDI displacement curves and for the ECG group as resulting in the narrowest QRS measured from the earliest deflection. At 6‐month follow‐up, percentage of echocardiographic responders (defined as neither death nor heart transplantation and a LV end‐systolic volume reduction >10%) was higher in the ECG optimized group (50.0% vs 67.9%; P = 0.023), whereas clinical response (defined as neither death nor heart transplantation and >10% improvement in the 6‐minute walking test) was similar in both groups (71.8% vs 73.1%; P = 0.858). Conclusions: VV optimization based on QRS width obtained a higher percentage of responders in terms of LV reverse remodeling compared to the TDI method. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1129‐1134, October 2011)     

Prospective comparison of echocardiographic atrioventricular delay optimization methods for cardiac resynchronization therapy

BACKGROUND: Atrioventricular (AV) delay optimization can be an important determinant of the response to cardiac resynchronization therapy (CRT) in patients with medically refractory heart failure and a ventricular conduction delay. OBJECTIVES: The purpose of this study was to compare two Doppler echocardiographic methods of AV delay optimization after CRT. METHODS: Forty consecutive patients (age 59 +/- 12 years) with severe heart failure, New York Heart Association class 3.1 +/- 0.4, QRS duration 177 +/- 23 ms, and left ventricular ejection fraction 26% +/- 6% referred for CRT were studied using two-dimensional Doppler echocardiography. In each patient, the acute improvement in stroke volume with CRT in response to two methods of AV delay optimization was compared. In the first method, the AV delay that produced the largest increase in the aortic velocity time integral (VTI) derived from continuous-wave Doppler (aortic VTI method) was measured. In the second method, the AV delay that optimized the timing of mitral valve closure to occur simultaneously with the onset of left ventricular systole was calculated from pulsed Doppler mitral waveforms at a short and long AV delay interval (mitral inflow method). RESULTS: The optimized AV delay determined by the aortic VTI method resulted in an increase in aortic VTI of 19% +/- 13% compared with an increase of 12% +/- 12% by the mitral inflow method (P <.001). The optimized AV delay by the aortic VTI method was significantly longer than the optimized AV delay calculated from the mitral inflow method (119 +/- 34 ms vs 95 +/- 24 ms, P <.001). There was no correlation in the AV delay determined by the two methods (r = 0.03). CONCLUSION: AV delay optimization by Doppler echocardiography for patients with severe heart failure treated with a CRT device yields a greater systolic improvement when guided by the aortic VTI method compared with the mitral inflow method.     

慢性心力衰竭患者CRT治疗前后心功能与超敏C反应蛋白变化

目的观察慢性心力衰竭（CHF）患者行心脏再同步化治疗（CRT）前后心功能、超敏C反应蛋白（hs-CRP）变化及相互关系。方法对本院20例符合CRT置入指征的CHF患者行CRT,并于术后1个月、3个月、6个月行AV/VV优化,分别在术前、术后1个月、3个月、6个月采用胶乳凝集反应法测定hs-CRP水平,心脏彩超测定左室射血分数（LVEF）、左心室舒张末期内径（LVDd）、磁共振血管造影（MRA）、心脏超声测定室间隔及左室后壁收缩达峰时间延迟（SPWMD）等指标。结果 CRT治疗后患者的心脏功能明显好转,术后1个月、6个月心功能NYHA分级平均降低I级;LVEF、LVDd、MRA、SPWMD均逐渐好转（P〈0.05）,术后hs-CRP指标逐渐下降（P〈0.05）;NYHA分级与hs-CRP水平的下降具有相关性（r=0.78,P〈0.05）。结论 CHF患者行CRT治疗后,心功能可明显改善,hs-CRP与心功能存在负相关性。