超声三维斑点追踪评价不同心脏起搏方式对健康犬左心室功能的影响

目的 探讨超声三维斑点追踪成像技术评价不同心室位点心脏起搏对健康犬左室壁机械同步性和左室功能的影响.方法 分别采集10只健康开胸比格犬基础状态和右室心尖、左室心尖、左室侧壁起搏状态一个完整心动周期的左心室全容积实时图像;同步记录左室压力时间变化曲线并获取左室射血压力和收缩期压力最大上升速率.用超声三维斑点追踪分析软件分别提取不同状态左室壁径向三维应变图、左室壁径向三维峰值应变和左室收缩末期容积、舒张末期容积、射血分数、每搏输出量、心输出量.定性观察并比较不同状态左室壁各节段心肌的径向三维应变同步性.对定量参数进行配对t检验、卡方检验和直线相关分析.结果 ①左室心尖或侧壁起搏状态左室壁各节段心肌的径向三维应变不同步程度较右室心尖起搏状态明显.②左室心尖或侧壁起搏状态左室壁径向三维峰值应变显著减低的心肌节段数多于右室心尖起搏状态(9/16 对 2/16,P<0.05).③左室心尖或侧壁起搏状态左室壁整体径向三维峰值应变和左室每搏输出量、射血分数、心输出量均低于右室心尖起搏状态(P<0.05).④不同状态左室壁整体径向三维峰值应变分别与左室每搏输出量、射血分数、心输出量呈线性正相关(r=0.781～0.984,P<0.05).结论 左室心尖或侧壁起搏对健康犬左室壁机械同步性和左室功能的损害超过右心室心尖起搏.     

速度向量成像评价DDD起搏前后心室收缩功能

目的 应用速度向量成像(velocity vector imaging,VVI)技术分析DDD起搏前后心室心肌运动速度、应变、应变率变化规律,初步探讨VVI技术的应用价值.方法 对17例DDD起搏患者于术前术后采用VVI技术检测心室各节段心肌收缩期纵向运动速度、应变、应变率和径向运动速度、环向应变及应变率,并比较术前术后差异.结果 术前术后左、右心室各室壁基底段、中间段、心尖段收缩期纵向峰值运动速度依次递减,基底段的速度最大,心尖段的速度最小;收缩期纵向应变、应变率在基底段、中间段及心尖段差异无统计学意义.左心室各室壁收缩期径向峰值运动速度、环向应变及应变率差异无统计学意义.右室后间隔与游离壁术前、术后平均峰值运动速度与应变率和术后平均应变均高于左室后间隔与侧壁,术后右室平均应变及应变率均高于左室.与术前相比,术后左室平均应变显著降低.结论 VVI技术能准确地定量评价DDD术前后节段性室壁功能及其变化.     

定量组织速度成像对右心室不同部位起搏患者左心室收缩非同步性的研究

目的探讨定量组织速度成像(QTVI)评估右心室不同部位起搏对室间隔与左心室侧壁收缩非同步性的影响.方法彩色多普勒超声心动图对24例右心室心尖起搏(RVAP)、14例右心室流出道起搏(RVOTP)患者和20名健康者进行检查,应用QTVI对心尖四腔观的室间隔和左室侧壁二尖瓣瓣环水平、基底段、中段和心尖段8个心肌节段的同步组织运动速度曲线进行分析.结果RVAP患者起搏后室间隔收缩期速度峰(Sm峰)无明显改变,左心室侧壁收缩期速度峰(Sm峰)基底段和瓣环部较起搏前减小(P＜0.05),靠心尖段及中段相对大于基底段和瓣环部;RVOTP患者起搏后室间隔收缩期速度峰(Sm峰)较起搏前稍增大,以基底段明显(P＜0.05),左室侧壁收缩期速度峰(Sm峰)较起搏前稍减小,但差异无显著性意义(P＞0.05);另外,RVAP患者起搏后室间隔与左心室侧壁基底段收缩早期速度峰延迟明显延长(P＜0.001),RVOTP患者起搏后稍延长,但差异无显著性意义(P＞0.05).结论QTVI显示RVAP和RVOTP患者室间隔与左心室侧壁收缩的非同步性,且RVAP者更为明显.QTVI是定量评估心脏室壁运动同步性的好方法.     

超声组织追踪成像评价右心室不同位点房室顺序起搏左心室心肌力学状态差异性

目的应用二维超声组织追踪成像(two-dimensional ultrasound tissue tracking imaging,2DTT)评价右心室室间隔起搏(right ventricular septal pacing,RVSP)和右心室心尖起搏(right ventricular apical pacing,RVAP)左心室心肌力学状态差异性。方法 60例有症状缓慢性心律失常并接受永久双腔房室顺序起搏器植入术后患者,根据起搏部位不同分为RVSP组25例及RVAP组35例。均行超声心动图检查,分别获取心尖四腔、心尖三腔及心尖两腔二维图像,测量收缩期左心室节段纵向应变(longitudinal strain,LS)及节段纵向应变率(longitudinal strain rate,LSr)、左心室整体纵向应变(global longitudinal strain,GLS)、整体纵向应变率(global longitudinal strain rate,GLSr)及节段纵向应变达峰时间(peak time of longitudinal strain,Tsl),计算间隔-后壁延迟比率,比较两种右心室起搏位点左心室心肌力学状态差异。结果两组间临床特征及常规超声心动图测量参数差异无统计学意义(P0.05)。RVAP组LS值以及GLS值低于RVSP组,差异有统计学意义(P0.05)。RVAP组节段纵向应变达峰时间较RVSP组明显延长(P0.05),间隔-后壁延迟比率差异无统计学意义(P0.05)。结论与RVSP相比,RVAP造成了明显的左心室收缩不同步和左心室纵向收缩功能减低,RVSP是房室顺序心脏起搏较好的心室位点。     

超声斑点跟踪显像评价房室顺序起搏患者左心室收缩功能

目的探讨超声斑点跟踪显像技术评价房室顺序起搏患者左心室收缩功能的价值。方法用超声斑点跟踪显像技术分别检测房室顺序起搏心房起搏心房感知抑制型(AAI)模式患者10例(A组)、房室顺序起搏双心腔起搏双心腔感知触发和抑制型(DDD)模式患者10例(B组)及正常对照10例(C组)的左心室16个节段的径向位移、速度及应变指标,并与常规超声心动图测量所得左心室射血分数(EF值)进行相关分析和比较。结果三组间左心室EF值、收缩期16节段径向位移峰值均数、径向速度峰值均数与径向应变峰值均数差异均无统计学意义(P>0.05)。B组与C组相比,径向位移峰值在左心室下壁基底段、间隔基底段及心尖段降低,径向应变峰值在下壁及间隔心尖段降低,差异有统计学意义(P<0.05)。A组与C组相比,左心室各个节段的径向位移、径向速度与径向应变峰值差异均无统计学意义(P>0.05)。结论房室顺序起搏DDD模式时,左心室下壁及间隔的基底段和心尖段收缩功能降低,AAI模式时左心室节段性收缩功能无明显改变。     

超声斑点成像技术评价左心室长轴心肌节段应变与位移

目的 评价生理和病理状态下左心室壁长轴方向心肌节段应变、位移和内径改变及三者之间的相关性。方法 获取心脏起搏组（12例）、右束支传导阻滞组（13例）、对照组（14例）标准心尖四腔观；分别测量计算室间隔、侧壁的心尖和基底四个节段长轴峰值应变和位移以及舒张末和收缩末内径差值；比较各组问测值差异并分别进行各参数间的相关分析。结果 心脏起搏组室间隔基底段峰值应变大于心尖段（P〈0．05）；对照组侧壁基底段峰值位移及相对心尖段峰值位移大于右束支阻滞组和起搏器组（P〈0．05）；右束支阻滞组侧壁应变差与相对位移显著相关（r=-0．607，P=0．037）。结论 起搏导致的拳川隔基底段应变异常增高和右束支传导阻滞导致的心尖和基底节段峰值位移及相对位移降低将会减低左心室射I衄能力。未能在多数节段建立长轴应变、位移和内径的相关关系，表明心尖与基底相对扭转对心室收缩功能更为重要。     

速度向量成像评价DDD起搏前后心室收缩功能

目的 应用速度向量成像(velocity vector imaging,VVI)技术分析DDD起搏前后心室心肌运动速度、应变、应变率变化规律,初步探讨VVI技术的应用价值.方法 对17例DDD起搏患者于术前术后采用VVI技术检测心室各节段心肌收缩期纵向运动速度、应变、应变率和径向运动速度、环向应变及应变率,并比较术前术后差异.结果 术前术后左、右心室各室壁基底段、中间段、心尖段收缩期纵向峰值运动速度依次递减,基底段的速度最大,心尖段的速度最小;收缩期纵向应变、应变率在基底段、中间段及心尖段差异无统计学意义.左心室各室壁收缩期径向峰值运动速度、环向应变及应变率差异无统计学意义.右室后间隔与游离壁术前、术后平均峰值运动速度与应变率和术后平均应变均高于左室后间隔与侧壁,术后右室平均应变及应变率均高于左室.与术前相比,术后左室平均应变显著降低.结论 VVI技术能准确地定量评价DDD术前后节段性室壁功能及其变化.     

速度向量成像评价DDD起搏前后心室收缩功能

目的 应用速度向量成像(velocity vector imaging,VVI)技术分析DDD起搏前后心室心肌运动速度、应变、应变率变化规律,初步探讨VVI技术的应用价值.方法 对17例DDD起搏患者于术前术后采用VVI技术检测心室各节段心肌收缩期纵向运动速度、应变、应变率和径向运动速度、环向应变及应变率,并比较术前术后差异.结果 术前术后左、右心室各室壁基底段、中间段、心尖段收缩期纵向峰值运动速度依次递减,基底段的速度最大,心尖段的速度最小;收缩期纵向应变、应变率在基底段、中间段及心尖段差异无统计学意义.左心室各室壁收缩期径向峰值运动速度、环向应变及应变率差异无统计学意义.右室后间隔与游离壁术前、术后平均峰值运动速度与应变率和术后平均应变均高于左室后间隔与侧壁,术后右室平均应变及应变率均高于左室.与术前相比,术后左室平均应变显著降低.结论 VVI技术能准确地定量评价DDD术前后节段性室壁功能及其变化.     

速度向量成像评价DDD起搏前后心室收缩功能

目的 应用速度向量成像(velocity vector imaging,VVI)技术分析DDD起搏前后心室心肌运动速度、应变、应变率变化规律,初步探讨VVI技术的应用价值.方法 对17例DDD起搏患者于术前术后采用VVI技术检测心室各节段心肌收缩期纵向运动速度、应变、应变率和径向运动速度、环向应变及应变率,并比较术前术后差异.结果 术前术后左、右心室各室壁基底段、中间段、心尖段收缩期纵向峰值运动速度依次递减,基底段的速度最大,心尖段的速度最小;收缩期纵向应变、应变率在基底段、中间段及心尖段差异无统计学意义.左心室各室壁收缩期径向峰值运动速度、环向应变及应变率差异无统计学意义.右室后间隔与游离壁术前、术后平均峰值运动速度与应变率和术后平均应变均高于左室后间隔与侧壁,术后右室平均应变及应变率均高于左室.与术前相比,术后左室平均应变显著降低.结论 VVI技术能准确地定量评价DDD术前后节段性室壁功能及其变化.     

速度向量成像评价DDD起搏前后心室收缩功能

目的 应用速度向量成像(velocity vector imaging,VVI)技术分析DDD起搏前后心室心肌运动速度、应变、应变率变化规律,初步探讨VVI技术的应用价值.方法 对17例DDD起搏患者于术前术后采用VVI技术检测心室各节段心肌收缩期纵向运动速度、应变、应变率和径向运动速度、环向应变及应变率,并比较术前术后差异.结果 术前术后左、右心室各室壁基底段、中间段、心尖段收缩期纵向峰值运动速度依次递减,基底段的速度最大,心尖段的速度最小;收缩期纵向应变、应变率在基底段、中间段及心尖段差异无统计学意义.左心室各室壁收缩期径向峰值运动速度、环向应变及应变率差异无统计学意义.右室后间隔与游离壁术前、术后平均峰值运动速度与应变率和术后平均应变均高于左室后间隔与侧壁,术后右室平均应变及应变率均高于左室.与术前相比,术后左室平均应变显著降低.结论 VVI技术能准确地定量评价DDD术前后节段性室壁功能及其变化.     

Assessment of regional wall motion by strain Doppler during biventricular pacing in patients with conventional indications for a pacemaker

Biventricular pacing therapy is effective in patients with severe congestive heart failure. Strain Doppler imaging (SDI) is a new tool for measuring regional myocardial deformation. We evaluated regional wall motion by strain Doppler imaging in 13 patients who had conventional indications for a pacemaker (74 +/- 6 years old) and in six with NYHA Class III or IV heart failure with a biventricular pacemaker (HF-RV: during right ventricular pacing, HF-BV: during biventricular pacing). The other seven patients had normal LV function (N-RV). Wall motion was assessed by strain of the myocardium, and the interval between the Q wave of the surface ECG and the peak strain (QPSI) was measured in three septal and three lateral segments. Interventricular contraction delay was determined as the interval between the onset of the left and right ventricular outflow waves. Intraventricular contraction delay was determined as the time difference between minimum and maximum QPSI. Strain of HF-RV was significantly greater than that of N-RV (-9.6%+/- 2.5% vs -14.4%+/- 2.3%, P < 0.0001). Intraventricular contraction delay of HF-RV was significantly greater than that of N-RV (273 +/- 12 vs 151 +/- 69 ms, P = 0.0004). Strain of HF-RV was not significantly greater than that of HF-BV (-9.6% +/- 2.5% vs -10.6% +/- 2.9%). Interventricular contraction delay of HF-RV was greater than that of HF-BV (37.2 +/- 44.7 vs 16.2 +/- 47.4 ms, P < 0.0001). Intraventricular contraction delay of HF-RV was significantly greater than that of HF-BV (322 +/- 101 vs 209 +/- 88 ms, P = 0.0006). In conclusion, biventricular pacing improves both interventricular contraction delay and intraventricular contraction delay in patients with conventional indications for a pacemaker with severe congestive heart failure, and SDI is useful to predict the efficacy of biventricular pacing.     

Right ventricular outflow tract pacing: radiographic and electrocardiographic correlates of lead position

OBJECTIVE: To characterize the pacing site in an unselected series of patients undergoing right ventricular outflow tract (RVOT) lead placement and investigate the role of the electrocardiogram (ECG) in predicting implantation. BACKGROUND: Right ventricular apical pacing is associated with long-term adverse effects on left ventricular function, fuelling interest in alternative pacing sites, especially the RVOT. Previous studies have been conflicting, possibly due to poor definition of pacing site within the RVOT. METHODS: In 150 patients undergoing pacemaker implantation, implanters were asked to place the lead in the RVOT. Radiographs were performed in the antero-posterior (AP) and 40 degrees right and left anterior-oblique projections post procedure. Fifty-six had left lateral radiographs. Lead position was categorized using AP/RAO (right anterior oblique) to confirm RVOT placement and left anterior oblique to distinguish free wall from septum. A 12-lead ECG was performed during ventricular pacing. RESULTS: Leads were below the RVOT in 18. Of the remaining 132, the majority (94%) were in the inferior/low RVOT. Eighty-one out of 132 were septal and 51 free wall. Septal sites were associated with shorter QRS duration (134 ms vs 143 ms, P < 0.02). Free wall sites displayed more frequent notching of the inferior leads (P < 0.01). A negative deflection in lead I provided a positive predictive value of 90% for septal sites. In those with lateral radiographs, a posteriorly projected lead was 100% specific for septal placement. CONCLUSIONS: This study demonstrates the heterogeneity of lead placement within the RVOT. Septal and free wall sites display characteristic ECG patterns which may be used to aid placement. The left lateral radiograph is useful in confirming a true septal location.     

定量组织速度成像评价慢性心力衰竭患者左室壁收缩的非同步性

目的　探讨定量组织速度成像 (QTVI)评价慢性充血性心力衰竭 (慢性心衰 )患者左室壁收缩的非同步性。方法　应用 QTVI分析 16例慢性心衰患者和 2 0例正常人的左室壁运动速度曲线 ,并对其中 4例右室双灶起搏和 1例双心室起搏患者起搏前、后进行对比分析。结果　慢性心衰患者的室间隔和左室侧壁基底段的收缩期速度峰均明显减低 (P<0 .0 0 1) ,两节段的收缩期速度峰延迟明显 (P<0 .0 0 1)。5例患者起搏后室间隔和左室侧壁基底部收缩期速度峰均较起搏前稍增大 ,两节段的收缩期速度峰延迟较起搏前明显缩短。结论　 QTVI能够评价左室壁收缩的非同步性 ,并能够评估起搏治疗再同步化的效果。     

Septal Short Atrioventricular Delay Pacing: Additional Hemodynamic Improvements in Heart Failure

Controversy exists as to whether short AV delay pacing is beneficial in left ventricular dysfunction with the studies performed coming to disparate conclusions. The right ventricular apical pacing previously studied results in asynchronous contraction and relaxation sequences and may limit the potential benefits of short AV delay pacing. In this study the hemodynamic effects of septal (resulting in a more physiological activation sequence) and apical right ventricular activation were compared in 15 patients with heart failure. VDD pacing with AV delays of 50,100, and 150 msec was evaluated. Apical VDD pacing did not increase the cardiac output significantly, 4.1 ± 0.75 to 4.45 ± 0.74 L/min, whereas septal VDD pacing increased the cardiac output to 4.86 ± 0.79 L/min (P = 0.037). Apical pacing increased the cardiac output in 10 patients and septal pacing in 11 patients. We conclude that selected patients with ventricular dysfunction benefit from short AV delay pacing. Septal ventricular activation confers significant hemodynamic improvements over apical activation.     

Two-dimensional guided M-mode color tissue Doppler echocardiography in artificial preexcitation models.

The purpose of this study was to analyze the left ventricular contraction patterns in artificial preexcitation models by using 2-dimensional guided M-mode color tissue Doppler echocardiography. Three types of preexcitation models were produced in 12 patients by right atrio-mitral annular sequential pacing, carried out at the left ventricular lateral, posterior, and posteroseptal walls. Tissue Doppler M-mode was recorded at anteroseptal, posterior, lateral, and posteroseptal sites in the parasternal short-axis view. The time interval from the onset of the QRS complex during sinus rhythm or from the annular pacing spike during fusion beats to the beginning of systolic motion was measured. During sinus rhythm, the time interval at the anteroseptal wall was shortest. During fusion beats, the time intervals at the mitral annular pacing sites were shortest. In preexcitation models, tissue Doppler M-mode could clearly distinguish the difference of left ventricular contraction patterns and detect the earliest contraction site of the left ventricle.     

Effects of proximal ventricular septal pacing on hemodynamics and ventricular activation

Recently the use of alternate site pacing to improve cardiac function in patients with bradyarrhythmias has increased. In the present study, hemodynamics of right ventricular septal pacing were studied in seven dogs. A bipolar screw-in lead and endocardial lead were placed in the proximal right ventricular septum and right ventricular apex, respectively. The right ventricle was paced from each site. A conductance catheter and Millar catheter were inserted into the left ventricle to determine the left ventricular pressure and the pressure-volume loop. Cardiac output was measured using the thermodilution method. In five of the seven dogs, ventricular activation was documented by isochronal epicardial activation mapping during each pacing mode. Mean arterial pressure and cardiac output during septal pacing were significantly higher than during apical pacing (110 +/- 17 mmHg vs 100 +/- 18 mmHg; 1.00 +/- 0.39 L/min vs 0.89 +/- 0.33 L/min). The positive dp/dt during septal pacing was significantly higher than during apical pacing (2137 +/- 535 mmHg/s vs 1911 +/- 404 mmHg/s). End-systolic elastance during septal pacing was significantly higher compared to apical pacing (13.1 +/- 0.3 mmHg/mL vs 8.9 +/- 4.0 mmHg/mL). The ventricular activation time during septal pacing was significantly shorter than during apical pacing. The epicardial maps generated during septal pacing were similar to those from atrial pacing. We conclude that hemodynamics and interventricular conduction are less disturbed by proximal right ventricular septal pacing than apical pacing in dogs with normal hearts.     

右室间隔部与心尖部起搏影响心功能的对比分析

目的对比分析右室间隔部起搏和心尖部起搏对患者心功能的长期影响。方法连续选取高度以上房室传导阻滞患者分别行右室间隔部起搏和心尖部起搏,随访观察两组手术情况、电极参数变化、心电图、并发症、超声心动图改变。结果两组在手术时间、感知阈值、起搏阈值、QRS波宽度改变上差异有统计学意义,在电极阻抗方面差异无统计学意义;长期随访右室心尖部起搏组LVEDD、LVESD均较间隔部起搏者增加,LVEF减低。结论长期右室间隔部起搏较心尖部起搏对心功能影响更小。     

犬左心室不同激动顺序收缩期容量与压力的超声研究

目的 应用三维全容积成像技术评价正常犬收缩期左事整体和节段容量及压力变化,评价不同电机械兴奋顺序时左室整体及节段收缩功能与同步化程度.方法 19只开胸比格犬模型,分别在基础状态(BASE)和右心耳(RAA)、右室心尖(RVA)、左室侧壁(LVL)、左室心尖(LVA)起搏状态采集左室全容积图像;同步记录左室流出道收缩末压力(ESP);脱机分析左室收缩末容积(ESV)、左室舒张末容积(EDV),计算整体及17节段射血分数(EF)、节段容积同步化指数(SDI)、左室收缩期压力平均上升速率(+dp/dt)和舒张期压力平均下降速率(-dp/dt).对各参数行配对t检验、方差分析和线性相关分析.结果 ①RVA组左室整体EF、ESP、+dp/dt、-dp/dt较RAA组减低,SDI较RAA组增大(P<0.05);LVL组及LVA组整体EF与RAA组问差异均无统计学意义(P>0.05),ESP,+dp/dt、-dp/dt均较RAA组减低,SDI均较RAA组增大(P<0.05).②LVL组及LVA组EF均较RVA组增高,LVL组SDI较RVA组减低(P<0.05),LVA组SDI与RVA组间差异无统计学意义.③LVL组整体EF、SDI、ESP、+dp/dt及-dp/dt与LVA组间差异无统计学意义;LVA组间隔、心尖节段EF较LVL组减低(P<0.05).④RVA组前、后间隔、心尖(除侧壁外)节段EF较RAA组减低(P<0.05);LVL组侧壁、前壁节段EF较RAA组减低;LVA起搏组前壁、前间隔、心尖节段EF较RAA组减低(P<0.05).⑤左室容积与压力参数间未能建立线性相关关系.结论 RAA起搏左室整体及少数节段收缩功能低于窦性心律;RAA起搏左室收缩与舒张功能均优于心室起博;LVL起搏左室收缩功能明显优于RVA起搏;心室起搏后,起搏位点周围左室节段收缩功能下降.     

Localization of the Accessory Pathway in the Wolff-Parkinson-White Syndrome from the Ventriculo-Atrial Conduction Time of Right Ventricular Apical Extrasystoles

In 18 consecutive patients with the Wolff-Parkinson-White syndrome undergoing electrophysiologic study, the ventriculo-atrial conduction time of right ventricular apical extrasystoles which advanced atrial activation during circus movement tachycardia was studied in relation to accessory pathway location. Accessory pathway location was determined by delta wave morphology during maximal pre-excitation, mapping of alrial activation during circus movement tachycardia and ventricular pacing, the effect of bundle branch block on ventriculo-atrial conduction time during circus movement tachycardia, and the effect of pacing from different sites in the atria on the stimulus-to-delta wave interval. In 7 patients with septal accessory pathways, ventriculo-atrial conduction time was similar during circus movement tachycardia and following right ventricular apical extrasystoles (mean difference 0 ± 6 ms, range -5 to + 10 ms). In contrast, in 11 patients with a left free wall accessory pathway, ventriculo-atrial conduction time increased by 46 ± 15 ms (range 15 to 65 ms) following right ventricular apical exlrasystoles. Therefore, measurement of the ventriculo-atrial conduction time of right ventricular extrasystoles during circus movement tachycardia provides an easy way to distinguish between septal and left free wall accessory pathways. This finding may be of particular use in determining the location of concealed bypass tracts.