右心室流出道间隔部起搏的可行性和稳定性

目的:本研究通过右心室流出道间隔部(RVOT)起搏与右心室心尖部(RVA)起搏的比较,评价RVOT起搏在目前植入技术条件下的可行性和稳定性.方法:42例无器质性心脏病患者,平均年龄(63.5±10.4)岁,随机分到RVA组(n=14)和RVOT组(n=28),所有患者均植入主动固定电极导线和带有自动起搏阈值测试功能的起搏器.通过手术时间、术中X线曝光时间及术中电极导线的各项参数评价RVOT起搏的可行性;通过急、慢性期起搏阈值及并发症评价RVOT起搏的稳定性.结果:RVA组和RVOT组的手术时间、曝光时间、术中电极导线各项参数等指标差异均无统计学意义(P均>0.05);RVOT组急性期起搏阈值稳定性与RVA组相近(P=0.23);两组术后6个月时起搏阈值分别为(0.55±0.11)V和(0.54±0.09)V(P=0.787),差异无统计学意义;随访期中,两组并发症发生率亦相近.结论:在目前的起搏技术条件下,RVOT起搏的可行性和稳定性与传统的RVA起搏相近.     

电极导线在右室心尖部和右室流出道起搏的随访观察

目的评价螺旋电极导线行右室流出道(RVOT)间隔部起搏的可行性。方法连续入组195例具有植入起搏器适应证患者,术前随机分为螺旋主动固定电极导线的RVOT间隔起搏组(A组)和翼状被动固定电极导线的右室心尖部(RVA)起搏组(B组),两组中每例入选患者均分别行RVA和RVOT两个部位起搏测试,最后固定于相应的位置。比较两组术中手术时间、起搏参数、起搏QRS波宽度、手术成功率及起搏3个月、1年和2年后电极导线参数的变化。结果 A组99例,B组96例。两组起搏后QRS波宽度明显大于起搏前,B组起搏QRS波时限长于A组(176.46±24.54 ms vs 165.45±22.78 ms,P=0.001)。用于固定RVOT间隔部的曝光时间长于RVA。两组术中及术后并发症相似,R波振幅术后2年内及两组间无差别。术中A组起搏阈值高于B组(0.71±0.30 V vs0.56±0.19 V),术后2年内起搏阈值两组内及组间无差异。术后3个月时阻抗下降,A组的阻抗低于B组并持续整个随访期间。术后2年内超声心动图参数组内及组间无差别。结论采用螺旋主动固定电极导线进行RVOT起搏是安全可行的。     

实时三维超声心动图评价右室不同部位起搏对左室收缩同步性的近期影响

目的应用实时三维超声心动图技术评价VVI单腔起搏器置入右室流出道间隔部(RVOT)和右室心尖部(RVA)对左室收缩同步性的近期影响。方法40例房室传导阻滞及心动过缓需置入VVI单腔起搏器的患者,按起搏部位的不同分为RVOT组(n=20)和RVA组(n=20)。观察并比较两组置入起搏器后1周的起搏参数;术前及术后1周左室收缩同步性和心功能等指标。结果术后1周,两组起搏阈值、感知阈值、电极阻抗以及心功能无差异(P>0.05),RVOT组左室同步性指标术前与术后无差异(P>0.05),RVA组左室同步性指标较术前升高,且RVA组较RVOT组明显升高(P均<0.05)。结论VVI单腔起搏右室不同部位,RVOT较RVA更接近生理情况。     

右心室流出道与右心室心尖部起搏对心室收缩同步性和心功能的影响

目的研究右心室流出道(right ventricular outflow tract,RVOT)间隔部和右心室心尖部(right ventricularapex,RVA)起搏对心脏收缩同步性、收缩功能的影响,探讨RVOT间隔部起搏的意义。方法 50例病态窦房结综合征患者分为RVOT组(n=25)和RVA组(n=25),起搏器置入1个月后通过调整房室间期使心室节律全部为起搏节律或房室结自身下传节律,观察起搏参数,并行超声心动图检查。结果RVOT组与RVA组电极导线植入时间、X线曝光时间比较,差异无统计学意义(P>0.05)。全部患者未出现植入并发症。两组随访1个月时起搏参数比较,差异无统计学意义(P>0.05)。RVOT组和RVA组起搏后的QRS波时限较前明显增宽,差异有统计学意义[RVOT组:(135±8)ms vs.(88±8)ms,P<0.001;RVA组:(154±8)ms vs.(90±6)ms,P<0.001]。RVA组起搏后QRS波时限较RVOT组增宽更为明显,差异有统计学意义(P<0.001)。两组起搏后室间机械延迟(interventricularmechanical delay,IVMD)和室间隔-左心室后壁收缩运动延迟时间(septal-to-posteriowall motion delay,SPWMD)较起搏前均显著增加,差异有统计学意义(P<0.001)。RVA组起搏后IVMD和SPWMD绝对值较RVOT组显著延长,差异有统计学意义[IVMD:(38±7)ms vs.(24±5)ms,P<0.001;SPWMD:(118±21)ms vs.(60±11)ms,P<0.001]。两组左心室舒张末内径及左心室射血分数比较,差异无统计学意义(P>0.05)。结论右心室起搏会造成心室收缩不同步,RVOT起搏对心室收缩不同步的影响较RVA起搏小,提示RVOT起搏是较为生理的起搏位点。     

右室流出道放置心室除颤电极导线的研究现状

植入型心律转复除颤器的右室除颤电极导线通常放置于右室心尖部,但近来研究显示长期右室心尖部起搏会导致心脏收缩和舒张功能下降,另外,当右室心尖部起搏阈值和/或除颤阈值较高时,需改变除颤电极导线的放置位置,以达到最佳的治疗效果。相对于右室心尖部而言,右室流出道放置除颤电极导线有一定的优势。现对右室流出道放置除颤电极导线的相关问题做一简要的综述。     

心房颤动患者右心室流出道间隔部起搏的可行性与安全性的观察

目的:通过右心室流出道间隔部（RVOTS）起搏与右心室心尖部(RVA)起搏的比较,评价RVOTS起搏的临床可行性与安全性。方法: 选择慢性心房颤动（房颤）伴长R-R间歇或缓慢心室率需植入永久起搏器患者68例,随机分配到RVOTS组（n=34）和RVA组（n=34）,RVOTS组将螺旋电极导线主动固定于RVOTS,RVA组将传统的翼状电极被动固定于右心室心尖部。分别记录每例患者术中X线曝光时间;术中及术后15 min、1、6、12个月时电极导线测试参数以及是否有并发症发生;测量自身及术后起搏心电图的QRS时限。结果: RVOTS组术中X线曝光时间 (12.8±5.4)min较RVA组（9.5±2.1）min长（P<0.01）,但随着手术熟练程度的增加,RVOTS组X线曝光时间逐渐缩短并接近RVA组;RVOTS组电极导线植入即刻起搏阈值与RVA组无统计学差异,导线植入15 min后及术后1、6、12个月时两组间起搏阈值无统计学差异;两组间R波振幅及阻抗在术中及术后各时期均无统计学差异;RVOTS组起搏心电图的QRS时限较RVA组显著缩短［(146±16)ms vs. (155±13)ms,P<0.05］;术中及随访期内无电极脱位、阈值增高、心肌穿孔及心包压塞等并发症。结论: 使用主动固定电极导线进行RVOTS起搏安全可行,且心室激动的电同步性优于RVA组。     

右室流出道间隔部应用螺旋电极固定起搏对心功能的影响分析

目的比较右室流出道(RVOT)间隔部起搏和右室心尖部起搏(RVA)对心功能的影响,评估螺旋电极进行右室流出道间隔部起搏技术的可行性与安全性。方法选择有永久起搏器植入适应证的患者21例,分为右室流出道间隔部起搏组(试验组),右心室心尖部起搏组(对照组),以超声心动图(UCG)和心电图评价两组术前、术后血流动力学和QRS波宽度差异。结果术后平均随访6个月,结果显示RVOT起搏血流动力学优于RVA起搏(P<0.05),RVOT起搏QRS波宽度较RVA组缩短,有统计学意义(P<0.01)。结论利用螺旋电极进行右室流出道间隔部起搏基本可行且较为安全,右室流出道间隔部起搏的血流动力学参数优于右室心尖部。     

右心室起搏电极位置对心脏再同步化治疗老年慢性心力衰竭临床效果的影响

目的探讨不同右心室起搏电极位置对心脏再同步化治疗(CRT)老年慢性心力衰竭临床效果的影响。方法选择接受CRT的老年慢性心力衰竭病人84例,术中左室起搏电极位置为侧后壁者65例,非侧后壁者19例,根据术中右室起搏电极位置为右心室流出道间隔(RVOT)和右心室心尖部(RVA)分为RVOT组(n=34)和RVA组(n=50),比较各组病人治疗前后QRS波时限(QRSd)、纽约心脏病协会(NYHA)心功能分级以及心脏超声指标左室射血分数(LVEF)、左心室舒张末期内径(LVEDD)及左心室收缩末期内径(LVESD)的变化。结果RVA组LVEF显著高于RVOT组(P<0.05),NYHA分级、QRSd、LVEDD、LVESD在2组间差异均无统计学意义(P>0.05)。左心室起搏电极在侧后壁者中,RVA亚组LVEF显著高于RVOT亚组(P<0.05),NYHA分级显著低于RVOT亚组(P<0.05),QRSd、LVEDD、LVESD在2组间差异均无统计学意义(P> 0.05)。在非侧后壁者中,RVA亚组与RVOT亚组各指标差异均无统计学意义(P>0.05)。RVA组和RVOT组病人CRT有效率的差异均无统计学意义(P>0.05)。结论 CRT对老年慢性心力衰竭的疗效受双室起搏位置的综合影响,右心室RVA起搏可能较RVOT起搏更具有临床优势,尤其是对于左心室为侧后壁起搏者,将右心室电极置于RVA有利于获得更好的疗效。     

主动与被动电极植入右室心尖部或右室间隔部即刻起搏参数的比较

目的比较主动与被动电极(AE与PE)植入右室心尖部(RVA)或右室间隔部(RVS)对即刻起搏参数的影响。方法回顾植入永久起搏器的患者资料,比较AE和PE植入RVA时即刻起搏参数的差异,比较AE植入RVA或RVS即刻起搏参数的差异。结果入选399例,283例右室起搏电极植入RVA,AE 155例,PE 128例。AE者的起搏阈值高于PE者,而阻抗、感知低于PE者,电极类型是影响差异的唯一因素。271例右室起搏电极为AE,植入RVA 155例,RVS 116例。两部位仅阻抗有差异,起搏部位是影响差异的唯一因素。结论 AE和PE在植入RVA时起搏阈值、感知和阻抗的差异由电极类型不同所引起,而AE植入RVA和RVS即刻阻抗的差异归咎于起搏部位的不同。     

双腔植入型心律转复除颤器临床应用

目的以往应用的单腔心律转复除颤器(ICD)常会发生误识别，产生误放电。此外，单腔心室起搏可使心功能降低。双腔ICD可克服单腔ICD上述弊端。本文报道12例双腔ICD的临床应用。方法12例患者，男性10例，女性2例，平均年龄52岁，均有院外晕厥史，术前证实室性心动过速7例，心室颤动5例。12例患者中4例伴有阵发性心房颤动(房颤)，3例伴有阵发性房性心动过速(房速)，5例伴有心动过缓及心功能不良。12例患者均植入了双腔ICD(美敦力公司，Gem DR)。心室导线常规植入右心室心尖部，心房导线为主动固定的螺旋电极导线，此导线顶端带有弹簧除颤电极，将心房导线固定于右心耳靠外侧处，以避免发生交叉感知。结果12例患者均顺利植入双腔ICD，除颤阈值均小于20J。平均心室起搏阈值0．9V，R波高9．8mV。心房起搏阈值1.4V，P波高2．6mV。在平均随访6．8个月中，ICD共发放抗心动过速起搏(ATP)45次，低能量转复11次，除颤4次，无误放电发生。5例伴心动过缓者，心功能无进一步恶化。结论双腔ICD由于增加了心房电极导线，可提高对房性心律失常的识别能力，从而减少误放电。对伴有房性心律失常及心动过缓者应推荐使用双腔ICD。     

A randomized comparison of defibrillation thresholds in the right ventricular outflow tract versus right ventricular apex

OBJECTIVE: To determine whether the placement of an implantable cardioverter-defibrillator (ICD) lead in the right ventricular outflow tract (RVOT) has the same defibrillation threshold (DFT) as the right ventricular apex (RVA). BACKGROUND: Right ventricular ICD leads have usually been placed in the RVA. Development of active fixation technology has allowed the placement of these leads in alternate locations such as the RVOT. METHODS: At time of device implantation, 26 patients with either ischemic or dilated cardiomyopathy underwent DFT testing in both the RVA and RVOT using a binary search algorithm. RESULTS: Placement of the lead in the RVA had a mean DFT of 7.6 +/- 2.8 J while the placement of the lead in the RVOT had a mean DFT of 10.3 +/- 3.0 J. The median (25th and 75th percentiles) DFTs in the RVA and RVOT were 7.5 J (6 and 11 J) and 11 J (9 and 14 J), respectively (p = 0.0002). CONCLUSIONS: Placement of the right ventricular lead in the RVA has a significantly lower DFT than placement of the lead in the RVOT.     

An observational registry on efficacy and safety of the right ventricular outflow tract as a site for ICD leads: results of the EFFORT (EFFicacy Of Right ventricular outflow Tract as site for ICD leads) registry

Background  

Although pacing from the right ventricular outflow tract (RVOT) has been shown to be safe and feasible in terms of sensing and pacing thresholds, its use as a site for implantable cardioverter defibrillator (ICD) leads is not common. This is probably due to physicians’ concerns about defibrillation efficacy. To date, only one randomized trial, involving 87 enrolled patients, has evaluated this issue.     

右室流入道间隔部起搏对心脏血流动力学和心室激动顺序的影响

目的通过与右室心尖部(RVA)和右室流出道(RVOT)起搏比较,探讨右室流入道间隔部(RVIS)起搏对血流动力学和心室激动顺序的影响。方法选择24例阵发性室上性心动过速需行射频导管消融术(RFCA)且心功能正常和无室内传导阻滞的患者。在RFCA成功后,置入漂浮导管行血流动力学监测,用心室起搏电极以同一频率随机顺序起搏RVIS、RVOT和RVA,分别测定和比较各部位起搏时的心输出量(CO)、心脏指数(CI)、平均肺动脉压(mPAP)、肺毛细血管楔嵌压(PCWP)以及体表心电图上QRS波时限、JTc间期(经心率校正后的JT间期)和额面平均心电轴的变化。结果①RVIS、RVOT和RVA起搏时CO、CI、mPAP和PCWP等血流动力学指标均无差异(P>0.05)。②与正常窦性心律时QRS波时限比较,各部位起搏时QRS波时限均延长(P均<0.001),其中RVIS起搏时QRS波时限延长程度最小,RVA起搏时延长程度最大,各部位两两比较P均<0.05;JTc间期的变化有类似趋势,但各起搏部位之间比较无显著差异(P>0.05);与正常窦性心律时的额面平均心电轴比较,RVIS起搏时接近正常,RVOT起搏时电轴呈右偏趋势,RVA起搏时呈左偏趋势。结论①对心功能正常者RVIS起搏较RVOT和RVA起搏未表现出更佳的急性血流动力学效应。②RVIS起搏与RVOT和RVA起搏相比,能够保持相对正常的心室激动顺序。     

High dispersion of ventricular repolarization after an implantable defibrillator shock predicts induction of ventricular fibrillation as well as unsuccessful defibrillation

OBJECTIVES: To test the hypothesis that post-shock dispersion of repolarization (PSDR) is higher in T wave shocks that induce ventricular fibrillation (VF) than in those that do not, as well as in implantable cardioverter defibrillator (ICD) defibrillation shocks which fail to terminate VF when compared with those that are successful. BACKGROUND: Ventricular fibrillation has been linked to the presence of dispersion of repolarization, which facilitates reentry. Most of the studies have been done in animals, and the mechanism underlying the generation and termination of VF in humans is speculative and remains to be determined. METHODS: Monophasic action potentials (MAPs) were recorded simultaneously from the right ventricular outflow tract (RVOT) and the right ventricular apex (RVA) in 27 patients who underwent implantation and testing of an ICD. T wave shocks were used to induce VF while the termination was attempted using internal defibrillator shocks. The post-shock repolarization time (PSRT) was measured in both the RVA and RVOT MAPs, and the difference between the two recordings was defined as the PSDR. The averages of PSDR were compared between the successful and unsuccessful inductions and terminations of VF. RESULTS: T wave shocks that induced VF generated a greater PSDR (93.4 +/- 85.1 ms) than the unsuccessful ones (45.1 +/- 55.9 ms, p < 0.001). On the other hand, shocks that failed to terminate VF were associated with a greater PSDR (59.9 +/- 41.2 ms) than shocks that terminated VF (21.1 +/- 20.1 ms), p < 0.001. CONCLUSIONS: A high PSDR following a T wave shock is associated with induction of VF; while following a defibrillating shock, it is associated with its failure and the continuation of VF. Conversely, a low PSDR is associated with failure of a T wave shock to induce VF and successful termination of VF by a defibrillating shock.     

Comparison of the Acute Hemodynamic Effect of Right Ventricular Apex,Outflow Tract,and Dual‐Site Right Ventricular Pacing

Background: We studied the acute effect of pacing at the right ventricular outflow tract (RVOT), right ventricular apex (RVA) and simultaneous RVA and RVOT—dual‐site right ventricular pacing (DuRV) in random order on systolic function using impedance cardiography. Methods: Seventy‐three patients (46 males), aged 52–89 years (mean 71.4 years) subjected to routine dual chamber pacemaker implantation with symptomatic chronic II or atrioventricular block, were included to the study. Results: DuRV pacing resulted in significantly higher cardiac index (CI) in comparison to RVOT and RVA and CI at RVOT was higher than at RVA pacing (2.46 vs 2.35 vs 2.28; P < 0.001). In patients with ejection fraction >50% significantly higher CI was observed during DuRV pacing when compared to RVOT and RVA pacing and there was no difference of CI between RVOT and RVA pacing (2.53 vs 2.41 vs 2.37; P < 0.001). In patients with ejection fraction <50%, DuRV and RVOT pacing resulted in significantly higher CI in comparison to RVA pacing while no difference in CI was observed between RVOT and DuRV pacing (2.28 vs 2.21 vs 2.09; P < 0.001). Conclusion: Dual‐site right ventricular pacing in comparison to RVA pacing improved cardiac systolic function. RVOT appeared to be more advantageous than RVA pacing in patients with impaired, but not in those with preserved left ventricular function. No clear hemodynamic benefit of DuRV in comparison to RVOT pacing in patients with impaired systolic function was observed. Ann Noninvasive Electrocardiol 2010;15(4):353‐359     

右室心尖部起搏与右室流出道起搏对Ⅲ度房室传导阻滞患者疗效的对比研究

目的:比较右室心尖部起搏与右室流出道起搏对Ⅲ度房室传导阻滞患者心室间运动同步性及左室内运动同步性,以及对患者心功能的影响。方法:选取因Ⅲ度及高度房室传导阻滞患者置入双腔起搏器患者共38例。其中心室电极置入右室流出道者20例(RVOT组),置入右室心尖部18例(RVA组),超声心动图术前测量左室舒张末内径(LVEDD),左室收缩末内径(LVESD)、左室射血分数(LVEF)、E/A值、心室间激动延迟时间(IVMD)、室间隔与左心室后壁间收缩延迟时间(SPWMD)。术后1个月、12个月随访。结果:术后1个月,与RVOT组比较,RVA组IVMD、SPWMD明显延长[IVMD(39.83±6.01)∶(31.95±7.86)ms,P=0.02],[SP-WMD(97.83±20.81)∶(84.6±10.89)ms,P=0.023]。术后12个月,与ROVT组比较,RVA组LVEDD明显增大[(49.11±2.39)∶(47.4±1.96)mm,P=0.02],LVESD明显增大[(34.28±3.41)∶(32.5±1.5)mm,P=0.04];LVEF明显降低[(59.56±3.38)∶(62.8±2.14)%,...     

心脏选择性部位起搏的电和机械同步性研究的初步报告

目的观察心脏不同部位起搏时的电及机械同步性和血流动力学变化。方法14例患者分别于右室心尖（RVA）、希氏束部位（His）、右室高位流出道间隔部（RVOT）起搏,记录心输出量和心脏指数;比较不同部位起搏和自身心律时12导联体表心电图的QRS波宽度和方向,以评价电同步性;用全数字化超声诊断系统的向量速度显像评价机械同步性。结果心输出量和心脏指数在RVA起搏时较差,但差异无统计学意义（P〉0．05）。各部位起搏时QRS波的宽度：His为（124±5．3）ms,RVOT（144±7．1）ms,RVA（156±8．6）ms,均较自身心律（92±4．5）ms时宽（P〈0．01）;而His及RVOT均较RVA起搏时的QRS波时限窄,其差异有统计学意义（P〈0．01）。向量速度显像检查提示,RVOT起搏相对于RVA起搏有更好的机械同步性。结论RVOT可能较传统的RVA部位起搏好,同时手术操作容易。     

右心室心尖部起搏与右心室流出道起搏的临床研究

目的利用超声多普勒优化房室间期后,比较右心室心尖部（RVA）起搏与右心室流出道（RVOT）起搏对左、右心室间收缩同步性的差别。方法（1）共入选45例三度房室阻滞患者,其中男16例,女29例。RVA组31例,RVOT组14例,出院前进行程控。（2）将感知的房室间期（SAV）由70～170ms递增,每次递增20ms,分别行超声心动图检查,测定心肌做功指数（MPI）,将MPI最小时的SAV确定为最适SAV。比较不同起搏部位所测最适SAV的差异。（3）应用组织多普勒同步图（TSI）技术分别测量左、右心室侧壁基底部心肌收缩达峰时问,二者之差用ATs表示,代表室间不同步程度。比较不同起搏部位ATs的差异。结果（1）RVA与RVOT起搏的最适SAV分别为（80．0±9．8）ms对（92±18）ms,差异有统计学意义（P〈0．01）。（2）RVA与RVOT组室间隔与左心室侧壁收缩达峰时间差分别为（89．5±25．7）ms对（27．94-10．5）ms（P〈0．001）,左、右心室侧壁基底部收缩达峰时间之差分别为（88．3±23．4）ms对（29．54-16．7）ms,差异有统计学意义（P〈0．001）。结论与RVA起搏比较,RVOT起搏对心室收缩同步性影响较小,分析其效果与RVOT起搏部位有关。     

Arrhythmogenic right ventricular dysplasia presenting as right ventricular outflow tract tachycardia.

A case of a 51-year old male is presented. A left bundle branch block inferior axis tachycardia was manifest. At electrophysiological study this tachycardia was inducible and was ablated in the septal right ventricular outflow tract (RVOT). Two other tachycardias were identified both with right bundle branch block (RBBB) morphology raising the suspicion of diffuse pathology. Arrythmogenic right ventricular dysplasia (ARVD) was confirmed by right ventricular angiography and magnetic resonance imaging (MRI). An implantable cardioverter defibrillator (ICD) was implanted and an appropriate shock was later delivered.