多普勒超声心动图评价DDD双腔起搏器房室间期血流动力学作用

双腔起搏器所选定的房室间期 (ＡＶＰ)仅仅确定了右房室之间的电激动顺序 ,并未解决房室之间特别是左房室间机械性运动的相互关系。对其最佳ＡＶＰ研究目前尚有争论。因此 ,本研究使用多普勒超声心动图在一组心功能正常患者中研究不同ＡＶＰ时血流动力学改变及发生机制。一、资料与方法1 对象 :按置ＤＤＤ起搏器患者 12例 ,男 8例 ,女 4例 ,平均年龄 (4 9± 15 )岁 ,均经Ｘ线胸片和超声心动图等系统检查而确定心脏舒缩功能正常。起搏器按置时间为 (13± 7)个月。2 方法 :平卧下调控起搏形式为起搏心房和心室 ,心率80次 /ｍｉｎ ,ＡＶＰ被分…     

不同方式、不同房室间期起搏对心脏射血与充盈的影响

应用多普勒超声心动图对11例病人进行了心房同步、房室顺序、心室按需三种方式起搏以及房室顺序起搏时房室间期分别为100,150,200,250ms时的心功能变化比较。结果表明:心房同步、房室顺序起搏时,心排指数分别较心室按需起搏增加37.1％、36.2％。房室顺序起搏的房室问期延长时,E峰的峰值流速、时间速度积分值降低,A峰的时间速度积分值增高。其原因是由于房室间期延长时,心房收缩人为提前,使A峰血流与E峰血流重叠所致,故而在估价心室舒张功能时应加以区别。     

双腔心脏起搏时房室间期与血流动力学关系的研究现状

双腔心脏起搏时房室间期与血流动力学关系的研究现状解放军总医院心内科杨曙光综述王思让审校双腔心脏起搏时房室间期（ＡＶＩｎｔｅｒｖａｌ，ＡＶ间期）的长短与起搏的血流动力学效应关系密切，因此，双腔起搏时选择合适的ＡＶ间期有重要的临床意义。本文简要综述国外有...     

超声心动图评价双腔起搏器不同房室间期设置时心功能变化

目的采用超声心动技术评价双腔起搏器设置不同房室间期（AVD）时的急性血流动力学和心脏收缩舒张功能改变。方法36例高度或Ⅲ度房室传导阻滞安装双腔起搏器的患者,在常规设置AVD和根据体表心电图优化设置AVD的情况下分别进行超声心动图检查。结果与常规设置AVD相比,AVD优化后左室舒张末期容积、左室每搏量、左室射血分数和心排量显著增加,左室充盈时间延长,二尖瓣血流速度时间积分显著增加,Tei指数显著减小。此外,AVD优化后组织多普勒指标室间隔、左室前壁、下壁基底段收缩期峰值速度（Sm）显著增高,左、右心室壁基底段舒张晚期峰值速度（Am）显著增高,右室游离壁基底段的Sm、舒张早期峰值速度和Am均显著高于左室壁各基底段。结论双腔起搏器最佳AVD设置能改善患者的血流动力学指标和心脏功能,这些变化可用超声心动图来评价。     

应用超声心动图对双腔起搏器起搏房室间期的优化

目的 应用超声心动图技术观察双腔起搏器不同起搏房室间期(pacing atrioventricular delay,PAVD)起搏对即时左心收缩及舒张功能的影响.方法 40例三度房室阻滞行永久双腔起搏器植入的患者,采用彩色多普勒超声对PAVD进行优化,以超声心动图左心室最大心排出量(CO)为最佳PAVD,比较不同PAVD下左心室收缩及舒张功能.结果 不同PAVD产生不同左心室CO,最佳PAVD平均为(155.7±20.4)ms,其中70%患者PAVD为150 ms及175 ms;当最佳PAVD时舒张功能指标Tei指数,二尖瓣环室间隔速度(E'),二尖瓣血流频谱E峰/二尖瓣瓣环室间隔速度(E/E')等指标均处于最佳水平.结论 调整DDD起搏器PAVD不但能够改善左心室收缩功能,也可对舒张功能产生良性影响,植入DDD起搏器患者应加强随访,调整优化PAVD使起搏器发挥最佳效应.     

DDD起搏最佳房室延迟的设置及血流动力学评价

目的 对不同房室延迟DDD起搏患者进行血流动力学评价,探讨DDD起搏最佳房室延迟的设置方法。方法 应用超声心动图研究17例植入DDD起搏器患者不同AV间期时心排出量（CO）、舒张期二尖瓣返流（DMRD）、A波结束至二尖瓣完全关闭时间间期及同步心电图QT间期等的变化。结果（1）当 AV延迟调至（16.9±19.9）ms时,A波结束与二尖瓣关闭同时出现,此时将AV延迟分别延长20ms、40ms、60ms、80ms,A波结束至二尖瓣完全关闭的间期分别延长（13.9±3.7）ms、（31.5±5.1）ms、（52.8±4.1）ms、（72.4±4.0）ms,而且在此间期可发现舒张期二尖瓣返流;（2）CO最大时的AV延迟（即最佳房室延迟）与预测的最佳 AV延迟呈明显正相关（r=0.893,P<0.05）;（3）临界AV间期与最佳AV间期有显著正相关（r=0.884,P<0.05）,临界AV间期较最佳AV间期长;（4）临界AV间期及其后不同AV间期预测的最佳AV间期之间差异均无显著性（P>0.05）。结论 （1）临界AV间期可代表最佳AV间期的上限,可用临界AV间期减去A波结束至二尖瓣完全关闭的时间间期来预测最佳AV间期;（2）最佳AV延迟可按以下公式预测:先设置一个较长的AV间期,然后于超声心动图下测量A波结束至二尖瓣完全关闭的时间间期,则最佳AV间期等于此较长的AV间期减去A波结束至二尖瓣完全关闭的     

双腔起搏房室延迟时间对心功能的影响

目的观察不同房室延迟(AVD)的双腔起搏对心脏收缩、舒张功能的影响及不同心功能状态下的优化AVD。方法测量20例心力衰竭患者及10例心功能正常者(对照组)不同房室延迟起搏的急性血流动力学效应,同时以脉冲多普勒超声心动描记术测量心脏收缩、舒张功能指标。结果心力衰竭组房室延迟在134±13、131±12、136±10ms起搏时,血流动力学指标及左心室收缩功能、右心室舒张功能指标较AVD基线穴100ms雪及250ms显著改善;140±17ms起搏时,左心室舒张功能指标较AVD基线及250ms显著改善。对照组AVD在162±14ms起搏时,血流动力学参数较AVD基线及250ms显著改善。结论优化AVD可即刻改善心力衰竭患者心脏收缩及舒张功能,优化AVD随心功能状态不同而改变。     

不同房室间期对右室起搏比例影响的研究

目的：研究不同AV间期对右室起搏比例的影响,并探讨如何进一步进行AV间期的优化。方法：2012年9月至2015年12月,入选在我院接受圣犹达双腔起搏器植入患者,根据病因,分为“病窦综合征（SSS）”及“房室传导阻滞(AVB)”组。所有患者为DDD起搏模式,植入时默认AV间期PV/AV：150/170ms（5286型）及150/200ms（5816、5826型）;植入两个月后,AV间期设为PV/AV：325/350ms;植入4个月后,打开自动自主传导搜索功能（5286型）及VIPTM功能（5816、5826型）,PV/AV按照5286型起搏器固定参数设置,即每间隔5分钟搜索3个心动周期,并设置搜索时间120ms。每次随访时记录心室起搏比例,以秩和检验比较不同设置对起搏比例的影响。结果： SSS组入选38例,AVB组入选41例。SSS组一例患者因持续性心房颤动终止研究。两组患者中,默认设置、最长AV间期设置及自主传导搜索设置时起搏比例中位数分别为：37% 、3%、5%（SSS组）,83%、50%、54%（AVB组）三种设置间差异存在显著性（P<0.05）,从数值上看,SSS组差异更显著。结论：可以通过延长AV间期减少右室起搏,但对起搏器治疗患者,首先推荐个体化设置。     

高血压病心功能不全Doppler超声图的表现及意义

目的：研究高血压病心功能不全（HD）的Doppler超声表现形式及临床意义。方法：采用2500型多功能超声心动图78例高血压病HD患进行检测。结果：轻度HD组：以E／A（二尖瓣舒张早期最大流速／舒张晚期最大流速）＜1．S／D（肺静脉收缩期最大流速／舒张期最大流速）＞1为多，占74．3％；中度HD组：以1＜E／A＜2．S／D＜1为多，占70．8％；重度HD组：以E／A≥2，S／D＜1为多，占80％。单纯左室舒张功能障碍或左室收缩功能障碍并存时，E／A、S／D比值的变化规律与高血压病不同程度NYHA心功能分级的相似。结论：测定高血压病患的E／A、S／D对于评价其心功能、预后，指导治疗有重要意义。     

Relationship between atrioventricular delay, QT interval and cardiac function in patients with implanted DDD pacemakers.

QT interval may change when cardiac function is improved by optimizing the atrioventricular the (AV) delay. The relationship between AV delay, QT interval and cardiac function in patients with implanted DDD pacemakers was studied in 12 patients (aged 71+/-12 SD years) with complete or high degree AV block. Cardiac output (CO) was measured using a Swan-Ganz catheter or by continuous Doppler echocardiography. The pacing rate was fixed at 70-80/min to eliminate the influence of heart rate. The AV delay was prolonged stepwise by 30 ms starting from 90 ms. All measurements were performed after 5 min of pacing. When the AV delay was prolonged, the CO and QT interval gradually increased and reached a peak, and then decreased. When the CO was increased from the minimum to the maximum value by optimizing the AV delay, the QT interval was significantly prolonged from 440+/-40 to 456+/-39 ms (P<0.002). The CO increased from 5.5+/-2.5 to 6.0+/-2.5 l x min(-1) (P<0.002) when the AV delay was changed, during which the QT interval was prolonged from the minimum to the maximum value. There was a significant positive correlation between the optimal AV delay at which CO was maximal (161+/-33 ms) and the optimal AV delay predicted from the maximum QT interval (167+/-29 ms, r=0.85, P<0.001). In conclusion, the optimal AV delay can be predicted from the QT interval.     

Effects of variation of atrioventricular interval on left ventricular diastolic filling dynamics and atrial natriuretic peptide levels in patients with DDD pacing for complete heart block.

AIMS: This study was designed to evaluate the effect of variation of atrioventricular (AV) interval (AVI) on left ventricular (LV) diastolic function and ANP and c-GMP levels during DDD pacing in patients with complete AV block and normal systolic function. METHODS: The study population comprised 22 patients (mean age 65.2+/-14.3, 12 males) with complete AV block. All patients underwent complete Doppler echocardiography before implantation of a DDD-pacemaker. Twenty-four hours later, patients were paced for a period of 30 min, at three different AVIs (100 ms, 150 ms and 200 ms), at rest. During each pacing period, Doppler-derived LV diastolic indices were re-evaluated and ANP and c-GMP levels were reassessed. RESULTS: Overall comparison showed a significant progressive augmentation, from 200 ms to 100 ms AVI, in transmitral E/A wave ratio (from 0.53+/-0.13 to 0.90+/-0.25, P = 0.0005) and in LV filling time (from 0.33+/-0.05 to 0.40+/-0.06s, P = 0.0005), followed by a significant progressive reduction in ANP and c-GMP levels. An AVI of 100 ms or 150 ms was associated with improved diastolic indices and lower natriuretic peptides levels, compared with the longer AVI. CONCLUSION: Programmed AVI during DDD pacing affects LV diastolic performance and plasma ANP and c-GMP levels. The assessment of these parameters constitutes a useful modality for AVI optimization.     

Optimal atrioventricular delay setting determined by evoked QT interval in patients with implanted stimulus-T-driven DDDR pacemakers.

Cardiac function is improved by optimizing the atrioventricular (AV) delay. An automatic optimizing function of AV delay may be necessary to achieve the most favourable haemodynamic state in paced patients. The QT interval may change when cardiac function is improved by optimizing the AV delay. The QT or stimulus-T interval is used as a sensor for rate-responsive pacemakers. Evoked (e) QT interval is measured as the time duration from the ventricular pace pulse (stimulus) and the T-sense point that is the steepest point of the intracardiac T wave (stimulus-T interval). The relationship between AV delay, eQT interval and cardiac function was studied in 10 patients (73 +/- 10 (SD) years old) with an implanted stimulus-T-driven DDDR pacemaker. Cardiac output (CO) and pulmonary capillary wedge pressure (PCWP) were measured by Swan-Ganz catheter. The AV delay was prolonged stepwise by 30 ms. Electrocardiogram event markers which indicated ventricular spike and sensed T wave were recorded, and the interval between two event markers was measured as eQT interval. When AV delay was changed from 240 ms to the AV delay at which CO was maximal (172 +/- 33 ms), eQT interval prolonged from 346 +/- 60 to 353 +/- 62 ms (P < 0.01). There was a significant positive correlation between the optimal AV delay at which CO was maximal (172 +/- 33 ms) and the optimal AV delay which was predicted from the maximum eQT interval (179 +/- 37 ms, r = 0.92, P < 0.001). When AV delay was changed from 240 ms to the predicted optimal AV delay, CO increased from 4.2 +/- 0.7 to 4.5 +/- 0.81.min-1 (P < 0.001) and PCWP was decreased from 7.1 +/- 4.0 to 5.7 +/- 3.1 mmHg (P < 0.05). In conclusion, the optimal AV delay can be predicted from the eQT interval which is sensed by an implanted pacemaker. Automatic setting of the optimal AV delay may be achieved by the QT sensor of an implanted pacemaker.     

Doppler echocardiographic methods for optimization of the atrioventricular delay during cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is beneficial for a majority of patients with medically refractory heart failure due to severe left ventricular (LV) systolic dysfunction and prolonged interventricular conduction to improve symptoms and LV performance. An optimally programmed atrioventricular delay (AVD) during CRT can be also important to maximize the response in left ventricular function. Several Doppler echocardiographic methods have been reported to be useful for determination of the optimal AVD. This review will discuss the various Doppler-based approaches to program the AVD in patients that receive CRT.     

Doppler echocardiography during transesophageal atrial pacing in the detection of coronary artery disease Stress Doppler echocardiography in the detection of coronary artery disease

The aim of this study was to assess the applicability of the Doppler echocardiogram (EchoKG) during transesophageal atrial pacing (TAP) with respect to the detection of coronary artery disease (CAD). Aortic flow peak velocity (PV), mean acceleration (MA), stroke distance (SD), minute distance (MD) and time to PV were measured using pulsed Doppler EchoKG during sinus rhythm and at pacing rates of 120 and 140 bpm in 11 patients, taken as subjects, with CAD defined by coronary arteriography and 15 patients without CAD (the control group). Similar changes of PV, SD, MD and time to PV during TAP were observed in subjects with and without CAD. Only changes of MA were different between subjects with and without CAD:MA during TAP remained unchanged in the control group and decreased from 1055.2±49.7 cm/s² (baseline) to 829.0±55.9 cm/s² at a pacing rate 140 bpm (p<0.05) in subjects with CAD. On the basis of these data we suggest a new criterion for the detection of hemodynamically significant CAD: decrease of MA at a pacing rate of 140 bpm>15% of initial value. Its specificity and sensitivity in the detection of CAD were respectively 87% and 82%.We conclude that the Doppler EchoKG during TAP is a relatively simple and reliable method for the diagnosis of CAD, and that the response of the Doppler EchoKG parameter of MA to TAP is a sensitive and specific index, useful for the detection of significant coronary artery stenosis.     

心脏起搏器更换时单极心室电极参数的变化及其意义

目的:探讨更换起搏器时单极心室电极直接参数的变化及其临床意义。方法:对82例II~III度房室传导阻滞或病窦综合征患者,在起搏电能耗竭更换起搏器安置术中,应用起搏分析仪直接测量原心室起搏电极参数,并随访观察更换后起搏器功能变化情况。结果:至测量时原心室起搏电极在体内埋置时间为64~172,平均(109.2±26.4)个月,首次埋置时的起搏阈值为(0.64±0.32)V,更换脉冲发生器时为(1.55±0.62)V(P<0.05),更换脉冲发生器时,起搏电极阻抗(756.5±156.8)Ω,更换起搏脉冲发生器后,继续使用原心室起搏电极79例,术后随访1~151,平均(68.3±30.6)个月,3例于更换术后17~46个月,出现起搏器感知功能不良,重新手术时发现为导管不全断裂、绝缘层包鞘破损,其余病人起搏与感知功能均良好。结论:心室单极起搏电极使用约9年以后,大多电极的直接测量参数仍在良好范围,可以考虑继续使用,但必须注意随访,定期复查。     

实时三维超声心动图同步显像技术评价心脏再同步起搏治疗参数

目的:应用实时三维超声心动图三平面同步显像技术,评价扩张型心肌病行再同步起搏治疗不同起搏参数时的心肌同步性及心功能的变化。方法:采用实时三平面组织同步显像技术,同步实时获取心尖四腔观、左室心尖两腔观和左室心尖长轴观,局部心肌收缩达峰时间,采用牛眼图模式定量测量左室6个壁12个心肌节段的纵轴收缩达峰时间,测量指标为各节段的达峰时间最大延迟(Ts-max)及达峰时间标准差,同时测量左室射血分数及观察二尖瓣反流程度,观察双心室起搏前后及不同起搏参数时各指标变化。结果:双心室同步起搏后,患者心功能得到明确改善,左室射血分数从(25.3±7.6)%.提高至(39.5±13.9)%(P<0.05);左室舒张充盈时间增加,二尖瓣反流量减少;达峰时间最大延迟由术前的(434.1土215.6)ms缩短至(155.8±43.2)ms(P<0.05),达峰时间标准差由术前的(161.6土30.4)ms缩短至(63.9±21.8)ms(P<0.05);不同起搏参数时,上述各指标的改善程度不同。结论:实时三平面同步显像技术能够客观定量评价不同起搏参数下再同步化起搏治疗慢性心力衰竭的临床效果,双心室同步起搏治疗可改善心力衰竭患者的心功能,不同患者的最优起搏参数不同。