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。     

多普勒超声心动图在双腔心脏起搏最佳房室间期设置中的应用价值

目的 :探讨多普勒超声心动图在双腔心脏起搏最佳房室间期设置中的应用价值。方法 :19例患有完全性房室传导阻滞并植入永久性双腔心脏起搏器的患者 ,程控房室间期从 90ms逐渐递增至 2 5 0ms ,每次递增量 2 0ms ,脉冲多普勒测量不同房室间期时每搏量和二尖瓣血流频谱的变化。结果 :每搏量最大时的最佳房室间期为 (16 8.9± 15 .6 )ms ,二尖瓣血流频谱的A波终末与二尖瓣叶完全关闭信号同步时的房室间期为 (178.4±2 3.4 )ms ,两者之间存在良好的线性回归关系 (Y =86 .2± 0 .5X ,r =0 .70 ,SEE =11.5 ,P <0 .0 1)。结论 :多普勒超声可以对双腔心脏起搏时的最佳房室间期作出准确地选择 ,并且具有无创、可重复和简便易行的特点。     

房室间期优化对三度房室传导阻滞患者房室顺序起搏心功能的影响

目的:探讨不同房室间期(AVD)对三度房室传导阻滞(Ⅲ°AVB)患者房室顺序起搏(DDD)后心功能的影响。方法:接受DDD起搏治疗的Ⅲ°AVB患者16例,其中男女比例3∶1,平均年龄(64.50±15.96)岁。起搏器术后调整不同的AVD,应用左心导管检查测量左心室内压力上升/下降的速率(±dP/dT),评价不同AVD对Ⅲ°AVB患者DDD起搏后心功能的影响。结果:个体间最佳AVD的离散度较大(120～260 ms);不同AVD时,±dP/dT组内差异有统计学意义(P0.05),最佳AVD在160～220 ms区间的分布较集中;在160～220 ms区间的+dP/dT水平与其他区间的+dP/dT水平比较差异有统计学意义(P0.05);+dP/dT组最佳AVD与-dP/dT组最佳AVD比较差异无统计学意义(P0.05)。结论:不同的AVD对Ⅲ°AVB患者DDD起搏后心脏的收缩及舒张功能均有影响,最佳AVD能使其心脏的收缩及舒张功能达到最佳状态。     

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。     

双腔起搏器自动房室间期搜索功能对心房颤动发生的影响

60例置入双腔起搏器患者,分为房室间期搜索（Search AV）组（n=27）和非Search AV组（n=33）。术后6个月Search AV组较非Search AV组心房颤动（简称房颤）发生减少,房颤负荷降低。术后1年Search AV组房颤负荷仍低于非Search AV组。术后6个月及1年非Search AV组心室起搏比例高于Search AV组。心室起搏比例与房颤负荷正相关（P〈0. 05）。结论：双腔起搏器Search AV功能可明显减少心室起搏比例,降低房颤负荷,减少房颤发生。     

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…     

双腔起搏器突发起搏AV间期缩短四例

通过对4例双腔起搏器突发起搏AV间期缩短的心电图分析,阐述了引发起搏AV间期缩短的原因,其中1例因起搏器参数设置不当导致心室安全起搏脉冲发放,1例是开启AV间期负滞后搜索功能,1例是开启心室起搏管理功能(MVP),1例是开启心室起搏阈值自动检测功能。     

最小化心室起搏与超声心动图指导下优化房室间期的比较研究

目的：比较最小化心室起搏模式（ MPV）与超声心动图指导下优化房室间期（ OAVD）模式对病态窦房结综合征伴房室阻滞患者心功能及生活质量的影响。方法2009年9月至2012年6月于杭州市第一人民医院心内科就诊的40例诊断为病态窦房结综合征伴一度或二度房室阻滞植入双腔起搏器的患者采用随机数字表法分为2组：MPV组21例患者,开启MPV功能;OAVD组19例患者,在超声心动图指导下进行OAVD。在入组6、12个月后给予起搏器程控、6 min步行试验、明尼苏达生活质量评分、血浆脑钠肽（ BNP）、超声心动图等检查。结果两组患者基线指标差异无统计学意义。 MPV组患者的起搏房室间期显著长于OAVD组[（278．6±9．6） ms对（131．9±5．1） ms,P＜0．001）。 MPV组患者心室起搏比例在6个月后明显低于OAVD组（6个月：28．6%±37．8%对77．4%±37．5%,P=0．001;12个月：39．0%±41．5%对84．7%±31．1%,P=0．001）。两组患者血浆BNP水平、6 min步行试验、明尼苏达生活质量评分及超声心动图指标均差异无统计学意义（ P〉0．05）。结论 MPV虽能够显著降低心室起搏比例,但是在改善心功能及生活质量方面与OAVD差异无统计学意义。     

如何分析起搏心电图的房室间期

起搏心电图的起搏的房室间期(PAV)和感知的房室间期(SAV)间期并不是固定不变的,在心房感知功能不良、频率适应性AV延迟、AV滞后、心室安全起搏、非竞争性心房起搏、心室自动测阈值、起搏器特殊的程控模式、心室起搏管理等情况下,实际的PAV和SAV间期可能和程控值不同。随着起搏器现代功能的日益增多,多数情况下PAV和SAV间期和程控值不同并不是起搏器功能障碍,而是起搏器的特殊功能在发挥作用。     

右心室不同部位起搏对心脏收缩同步性及心功能的影响

目的比较右心室流出道（right ventricular outflow tract,RVOT）起搏与右心窀心尖部（riht ventficular apex,RVA）起搏对心脏收缩同步性指标及收缩功能的影响。方法2004年1月至2005年1月在我院植入VVL／VVIR,DDD／DDDR起搏器的患者,随机接受RVA起搏和RVOT起搏。植入前检查12导联体表心电罔及超声心动图,记录QRS时限、左心室舒张末内径（LVEDD）、左心房内径（LAD）、左心事射血分数（LVEF）。植入后记录心室起搏状态下的QRS时限。随访时间为2年,随访内容包括LVEDD、LAD、LVEF,同时应用脉冲组织多普勒技术测定心室问激动延迟（IVMD）以及左心室内收缩同步性指标（Ts-SD）。结果共随访30例患者,其中RVA起搏17例,RVOT起搏13例,两组患者间年龄、性别及心血管疾病等基本情况筹异无统计学意义。植入前两组患者问QRS时限、LVEDD、LAD及LVEF差异无统计学意义,植入后RVOT起搏状态下QRS时限较RVA起搏明显缩短[（140．15±11．36）ms对（160．76±23．68）ms,P=0．033],植入后两组间IVMD[（25．7±9．1）mS对（36．7±10．0）ms,P=0．076]比较差异无统计学意义,两组问Ts—SD（13．34ms对42．96ms,P=0．001）比较差异有统计学意义;植入后随访两年,两组患者间LAD差异无统计学意义[（43±6）ms对（42±9）ms,P=0．759],同RVA组相比,RVOT组LVEDD缩小[（5．10±0．76）mm对（5．28±0．40）mm,P=0．048],LVEF明显增加（0．56±0．04对0．52±0．02,P=0．001）。结论同右心窄流出道起搏相比,右心室心尖部起搏对患者心功能呈负性影响,且加重左心室内不同步收缩。     

Native QRS complex duration predicts paced QRS width in patients with normal left ventricular function and right ventricular pacing for atrioventricular block

Introduction

Prolonged paced QRS duration is a predictor of development of heart failure during chronic right ventricular pacing. One determinant of paced QRS width might be His-Purkinje system dysfunction, manifested in wide native (escape or conducted beat) QRS complexes in patients with atrioventricular (AV) block.

Methods

Fifty patients with normal left ventricular function who are undergoing implantation of a pacemaker for AV block were enrolled. The duration of the QRS complex was measured on the surface electrocardiogram during escape rhythm in 28 patients with total AV block and during conducted beats in 22 patients with second-degree, fixed ratio (2:1 or 3:1) AV block, as well as during ventricular paced rhythm after pacemaker implantation in all patients.

Results

A close, positive correlation was found between native and paced QRS duration in the second-degree AV block group (R = 0.74, P < .001). This association was also significant but less pronounced in the total AV block group (R = 0.46, P = .014).

Conclusion

Native QRS width, especially in case of fixed ratio (2:1 or 3:1) second-degree AV block, is a predictor of paced QRS duration in patients with AV block and normal left ventricular function. Wide QRS complex before implantation may carry a higher risk of developing heart failure with right ventricular pacing.     

Recovery of systolic and diastolic function after ablation of incessant supraventricular tachycardia

We report a case of a 26-year-old woman who presented to our hospital with arrhythmia and heart failure. She had an incessant supraventricular tachycardia, which was not reversible with electrical cardioversion. Echocardiogram showed a severe LV systolic and diastolic dysfunction. After radiofrequency catheter ablation, LV function returned to normal. This article is intended to show a case with tachycardiomyopathy, which is considered the most frequently unrecognized curable cause of heart failure, and to demonstrate that early treatment allows the recovery to a normal LV systolic and diastolic function, preventing irreversible structural cardiac damage. It is very likely that some patients with idiopathic dilated cardiomyopathy and chronic atrial fibrillation or other chronic arrhythmia actually have a curable tachycardiomyopathy.     

Acute pacing-induced dyssynchronous activation of the left ventricle creates systolic dyssynchrony with preserved diastolic synchrony

Introduction: Patients with heart block have conventionally received a pacemaker that stimulates the right ventricular apex (RVA) to restore heart rate control. While RVA pacing has been shown to create systolic dyssynchrony acutely, dyssynchrony can also occur in diastole. The effects of acute RVA pacing on diastolic synchrony have not been investigated. RVA pacing acutely impairs diastolic function by increasing the time constant of relaxation, decreasing the peak lengthening rate and decreasing peak negative dP/dt. We therefore hypothesized that acute RVA pacing would cause diastolic dyssynchrony in addition to creating systolic dyssynchrony.
Methods and Results: Fourteen patients (13 ± 4 years old) with non-preexcited supraventricular tachycardia underwent ablation therapy with subsequent testing to confirm elimination of the tachycardia substrate. Normal cardiac structure and function were then documented on two-dimensional echocardiography and 12-lead electrocardiography prior to enrollment. Tissue Doppler images were collected during normal sinus rhythm (NSR), right atrial appendage pacing (AAI), and VVI-RVA pacing during the postablation waiting interval. Systolic and diastolic dyssynchrony were quantified using cross-correlation analysis of tissue Doppler velocity curves. Systolic dyssynchrony increased 81% during RVA pacing relative to AAI and NSR (P < 0.01). Diastolic synchrony was not affected by the different pacing modes (P = 0.375).
Conclusion: Acute dyssynchronous activation of the LV created by RVA pacing resulted in systolic dyssynchrony with preserved diastolic synchrony in pediatric patients following catheter ablation for treatment of supraventricular tachycardia. Our results suggest that systolic and diastolic dyssynchrony are not tightly coupled and may develop through separate mechanisms.     

Optimizing diastolic filling by pacing in nonobstructive hypertrophic cardiomyopathy

1. Download : Download high-res image (101KB)
2. Download : Download full-size image

     

Assessment of heart failure and left ventricular systolic dysfunction after cardiac pacing in patients with preserved left ventricular systolic function

BACKGROUND: There is an accumulating data suggesting the deleterious effects of right ventricular pacing on left ventricular performance. Such pacing mimics left bundle branch block resulting in a prolonged QRS duration and causes ventricular asynchrony. AIMS: The purpose of this study is to assess heart failure and left ventricular systolic function after cardiac pacemaker implantation in patients with atrioventricular block and preserved systolic left ventricular function. Secondly, we sought to search for predictive factors of developing left ventricular dysfunction after pacing. METHODS: In this prospective study, we included patients who had been implanted for at least six months. They underwent medical history and examination, 12 leads electrocardiogram and echocardiography before pacemaker implantation and when attending to routine pacemaker follow up. RESULTS: Forty-three patients (22 men and 21 women, age 71+/-12 years) were included in this study. Twenty-nine patients had DDD pacing and 14 VVI pacing. The ventricular lead was implanted in the apex in all patients. After a median follow up of 18+/-11 months, 11 patients (25%) developed signs of congestive heart failure. NYHA was higher after implantation (1.64+/-0.7 versus 2.27+/-0.8, p>0.00001). Left ventricular ejection fraction decreased significantly during follow up (60+/-6% versus 51+/-13%, p=0.0002). Eleven (25%) patients developed left ventricular dysfunction. We compared patients who had left ventricular ejection fraction (LV EF) less or equal to 40% (group A) and patients having LV EF greater than 40% (group B) after implantation. Patients in group A had a paced QRS width significantly larger than group B (181+/-32 ms versus 151+/-26 ms, p=0.002), a significantly prolonged intra left ventricular electromechanical delay (115+/-59 ms versus 45+/-35 ms, p<0.0001) and interventricular delay (44+/-29 ms versus 27+/-18 ms, p=0.02). Age, sex, diabetes hypertension, pacing mode and percentage of ventricular pacing were similar in both groups. A paced QRS width of 180 ms had the best sensitivity and specificity for detecting left ventricular dysfunction: sensitivity=54% and specificity=93%, p=0.01, area under the curve=0.75. CONCLUSION: Patients with atrioventricular block and preserved left ventricular systolic function at baseline decrease significantly left ventricular ejection fraction after pacing. Induced ventricular asynchronism plays a major role in the deterioration of left ventricular function. Prolonged paced QRS width is a good predictor of left ventricular dysfunction after pacing. Larger prospective studies are needed to confirm these data.     

Reference right ventricular systolic and diastolic function normalized to age, gender and body surface area from steady-state free precession cardiovascular magnetic resonance.

AIMS: Recent advances in cardiovascular magnetic resonance (CMR) include improved image quality with steady-state free precession (SSFP) sequences and advanced post-processing of high temporal resolution ventricular function. We used these techniques to establish the reference values for right ventricular (RV) volumes and function. METHODS AND RESULTS: We studied 120 healthy subjects (60 men, 60 women; from 20 to 80 years) after exclusion of cardiovascular abnormality. Data were generated from SSFP cines, with three-dimensional modelling. Gender, body surface area (BSA), and age were independent predictors of several RV parameters. Normalized RV mass (RVM) and absolute and normalized RV volumes decreased significantly with age, whereas ejection fraction increased. For diastolic variables, absolute and normalized early peak filling rate (PFR(E)) decreased and absolute and normalized active peak filling rate (PFR(A)) in males increased, with decreased PFR(E)/PFR(A). Increasing BSA was associated with increased RVM, volumes, and PFR(E). Gender significantly influenced absolute and normalized mass and volumes, and absolute and normalized PFR(A). CONCLUSION: These data using state-of-the-art CMR show that normal values of RV systolic and diastolic parameters vary significantly by gender, BSA, and age. Appropriate reference ranges normalized to all three variables should be used in the determination of normality or severity of abnormality of RV dimensions and function.     

房室延迟对舒张功能不良患者左心房功能的影响

目的 探讨双腔起搏器不同房室延迟(AV间期)起搏对单纯舒张功能不良患者左心房功能的影响.方法 选择植入双腔起搏器的患者76例,分为单纯舒张功能不良组(38例)和心功能正常组(38例),应用超声心动图及应变率成像测算在不同AV间期时的心排出量(CO)、左心房射血分数(LAEF);收缩期、舒张早期和舒张晚期的左心房心肌平均峰值应变率(SR-s、SR-e和SR-a).结果 单纯舒张功能不良组:①AV间期自80 ms开始增至200 ms时,SR-a、LAEF和CO随AV间期的延长相应增大,在AV间期200 ms时达到最大,达峰值后逐渐下降,SR-a、LAEF和CO在AV间期＜150 ms及＞200 ms时较AV间期150 ～ 200 ms时降低(P＜0.05);②AV间期为80 ms时SR-s较AV间期为200 ms时增加明显(P＜0.05).心功能正常组:①随着AV间期变化,评价左心房功能的各指标无显著变化(P＞0.05);②CO在AV间期为150 ms时达到最大,在AV间期＜150 ms及＞200 ms时较AV间期为150～200 ms时降低(P＜0.05).结论 双腔起搏器不同AV间期可影响单纯舒张功能不良患者左心房的收缩功能,适当延长AV间期在生理上更有利于左心房功能的改善.     

Relation of genetic polymorphisms in microRNAs with diastolic and systolic function in type 2 diabetes mellitus

Background and aimsType 2 diabetes mellitus (T2DM) has high risk of developing cardiac dysfunction, increasing of either cardiovascular death or hospitalization for heart failure. MicroRNAs (miRNA) affect cardiac function of T2DM. The aim of this study was to investigate the relationships between five miRNA single nucleotide polymorphisms (SNP) and diastolic and systolic function of T2DM.Methods and resultsThree hundred untreated T2DM subjects were included. Each subject underwent SNP genotyping, conventional echocardiography, tissue doppler imaging, and speckle tracking imaging. The effects of miRNA SNPs on diastolic and systolic function were evaluated. The diastolic function of T2DM subjects with miR-133a-1-rs8089787 wild genotype or let-7f-rs10877887 variant genotype was lower than those with miR-133a-1-rs8089787 variant genotype or let-7f-rs10877887 wild genotype, manifesting as higher left atrial volume index, lower mean E′, and higher E/E’ (P < 0.05). There were no significant effects of miR-133a-2-rs13040413, let-7a-1-rs13293512 and miR-27a-rs895819 on the diastolic function of T2DM subjects (P > 0.05). These five miRNA SNPs had no effect on the systolic function of T2DM subjects (P > 0.05).ConclusionsMiRNA-133a-1-rs8089787 and let-7f-rs10877887 were associated with impaired cardiac diastolic function in T2DM. The findings may be a promising therapeutic targets for preventing diastolic dysfunction in T2DM.     

右室高位室间隔与心尖部起搏对心室收缩同步性和心功能的影响

目的探讨右室高位室间隔(HRVS)与右室心尖部(RVA)起搏对心室收缩同步性和心功能的影响及其机制,为右室高位室间隔起搏的临床应用提供理论基础。方法将具有行永久性双腔心脏起搏器植入术指征的77例患者,根据心室起搏电极植入部位的不同,随机分为HRVS起搏组(40例)和RVA起搏组(37例)。分别于术前、术后3个月和术后18个月,通过询问病史、查体、心电图和超声心动图检查对患者的一般临床状况、QRS波群时限(QRSd)、左右室射血前时间差值(LRVPEI)、室间隔与左室后壁收缩延迟时间(SPWMD)、左室射血分数(LVEF)进行观察随访。同时运用起搏器程控仪对患者术后3个月和18个月的起搏房室间期、心室起搏比例等起搏相关参数进行监测和调控。最后对两组患者的上述指标进行对比研究和统计学分析。结果两组患者一般临床特征及术前各项观察指标均无明显差别。术后3个月时,两组患者起搏相关参数均无显著差别(P<0.05),△HRVS起搏组的△QRSd、△LRVPEI和△SPWMD均明显小于RVA起搏组(P<0.05),LVEF无显著差别(P<0.05)。术后18个月时,两组患者间起搏相关参数没有明显差别,△QRSd、△LRVPE...