不同位点心室起搏对犬心脏作功效率影响的研究

通过不同位点心室起搏 ,探讨心室激动顺序对健康犬左心室功能、冠状动脉血流量 (CBF)、心肌耗氧量(MVO2 )和心脏作功效率 (CWE)的影响。选用健康蒙古犬 1 4只 ,顺序进行His束 (HisB)、右室尖部 (RVA)、左心室侧后壁 (LVPL)单点起搏及RVA LVPL、HisB LVPL双点同步心室起搏 ,每种方式起搏持续 2 0min ,间隔 1 0min或待基本血流动力学参数恢复到最初自身窦性节律水平后 ,进行下一方式起搏 ,以各种方式的最后 3min为标准时间段测量CBF、左心室功能参数、MVO2 相关参数并计算CWE。结果 :HisB、LVPL、HisB LVPL起搏时的心排血量 (CO) ,左室内压上升最大速率 (+dp/dtmax)、下降最大速率 (-dp/dtmax)以及CBF和CWE均明显优于RVA起搏 ,CO、+dp/dtmax、-dp/dtmax、CBF和CWE在HisB、LVPL和HisB LVPL起搏间比较无差异 ;RVA LVPL起搏较RVA起搏时CBF提高 30 % (P <0 .0 5) ,而CO、+dp/dtmax、-dp/dtmax和CWE也有提高趋势 ,但无统计学差异 ;MVO2 在此 5种心室起搏方式间无差异 ;HisB、HisB LVPL起搏较RVA LVPL起搏时CWE分别提高 1 7%和 1 4 % (P <0 .0 5)。结论 :对于健康犬心脏急性实验而言 ,在起搏介入条件下 ,保持正常的心室激动顺序和同步性有利于改善CBF ,提高左心室的收缩和舒张功能 ,改善CWE。     

不同心脏起搏方式对犬急性血液动力学及心肌力学的影响

通过采用 5种不同的心脏起搏方式 ,观察房室同步和心室激动顺序对犬急性血液动力学和心肌力学的影响。方法 :选用健康犬 10只 ,随机顺序进行右心房起搏 (RAP)、右房 His束顺序起搏 (AHSP)、右房 右室顺序起搏(AVSP)、His束近端起搏 (HBP)和右心室起搏 (RVP) ,在每种起搏稳定 5min后测定有关血液动力学和心肌力学参数。结果 :RAP和AHSP对血液动力学和心肌力学无显著影响 ;AVSP时心输出量 (CO)、等容收缩期左室压力最大上升速率 (+dp/dtmax)和等容舒张期左室压力最大下降速率 (-dp/dtmax)分别降低了 16 .32 % ,15 .0 1% ,15 .19% ;HBP时平均肺动脉压 (mPAP)、肺毛细血管楔压 (PCWP)、左室舒张末压 (LVEDP)均升高 ,而CO降低了 14.93 % ;RVP时mPAP、PCWP、LVEDP均明显升高 ,CO、+dp/dtmax和 -dp/dtmax分别降低了 2 3.95 % ,2 2 .2 8% ,19.74%。结论 :丧失房室同步活动引起左室前负荷变化 ,影响整体收缩功能 ;而心室激动顺序异常既影响左室收缩功能 ,也影响左室舒张功能     

心室起搏和房室顺序起搏的血流动力学研究

采用超声心动图研究心脏起搏前、后的血流动力学变化 ,以评价不同起搏模式的血流动力学效应。对 32例置入人工心脏起搏器的病人 ,采用M型、二维及多普勒超声心动图检测了心室按需起搏 (VVI)不伴室房逆传 (A组 )和伴室房逆传 (B组 )及房室顺序起搏 (DDD) (C组 )的左心结构、左室的泵血功能、左室收缩及舒张功能指标。结果 :①A组和C组起搏后的心输出量 (CO)明显增加 (P <0 .0 5 ) ,而B组则CO增加不明显 (P >0 .0 5 )。心搏量 (SV)各组均呈下降的趋势 ,B组下降更为明显。但起搏后三组间比较无显著性差异 (P >0 .0 5 )。②心室起搏后左室的收缩及舒张功能均有受损 ,而C组主要损害左室的舒张功能 ,对左室的收缩功能影响不明显。③B组起搏后血流动力学效应在三组中最差。结论 :无论心室 ,还是房室顺序起搏后 ,由于心率的增加均可使CO增加 ,但对左室的功能均有不同程度的损害 ,心室起搏伴室房逆传者最重 ,不伴室房逆传者次之 ,房室顺序起搏损害程度最轻     

DDD房室顺序起搏对慢性心力衰竭左室重构的逆转效应

目的　评价右房 -右室间隔上部顺序 DDD起搏 (RA- URIS)对慢性心力衰竭患者左室重构的逆转效应。方法　 37例病态窦房结综合征或房室传导阻滞伴心力衰竭的患者随机分为 RA- URIS组 (1 8例 )和右房 -右室心尖起搏治疗 (RA- RVA)组 (1 9例 ) ,比较术前和术后 1 2个月的左室舒张期末径、左室心肌重量指数、左室射血分数、6min步行距离测试和生活质量评分。结果　 RA- URIS组 1年后左室心肌重量指数 (1 0 2 .5± 1 6.3g/m2 )较术前 (1 1 0 .1± 1 8.5g/m2 )明显下降 (P<0 .0 5) ,左室射血分数 (38.3%± 1 0 .1 % )较术前 (30 .7%± 8.4% )明显提高 (P<0 .0 5) ;而 RA- RVA组上述指标较术前无明显变化。RA- URIS组术后 1年较 RA- RVA组左室心肌重量指数明显下降 (P<0 .0 5) ,左室射血分数 (33.7%± 5.5% )明显提高 (P<0 .0 5)。 RA- URIS组术后 1年 6 min步行距离测试明显提高 (386± 69m,330± 78m,P<0 .0 5) ,生活质量评分较术前明显下降 (2 3± 2 0 ,40±2 5,P<0 .0 1 ) ,而 RA- RVA组则没有明显变化。结论　 RA- URIS顺序起搏能逆转慢性心力衰竭患者的左室重构 ,改善生活质量。     

不同位点组合双室同步起搏对慢性缺血性心力衰竭猪心肌力学的影响

目的探讨不同位点组合双室同步起搏模式对慢性缺血性心力衰竭猪心肌力学的影响。方法7只慢性缺血性心力衰竭猪模型采用自身对照方法,对每一只动物随机组合为右房-右室心尖-左室后侧壁(RARVALVPL)、右房-右室心尖-左室尖(RARVALVA)和右房-右室心尖-左室后侧壁-左室尖(RARVALVPLLVA)起搏模式。分别比较不同起搏模式下的左室内压上升/下降最大速率(±dp/dtmax)、左室松弛时间常数(τ)。结果RARVALVPLLVA起搏模式的±dp/dt分别较RARVALVPL、RARVALVA起搏模式显著提高,τ值明显下降(P均<0.05),而RARVALVPL起搏模式和RARVALVA起搏模式之间±dp/dtmax、τ值无显著性差异(P>0.05)。结论RARVALVPLLVA起搏模式在保持房室激动顺序和双室同步起搏的同时,还能改善心室内的电机械同步性,较其他双室起搏模式具有更好的心肌力学效应。     

不同部位起搏对心脏收缩功能的影响

通过不同部位起搏 ,观察房室同步和心室激动顺序对人体心脏收缩功能的影响及起搏体表心电图QRS波时限与心输出量 (CO)的关系。 1 5例射频消融术后的病人分别按顺序进行右房、右室心尖部和室间隔起搏 ,采用心导管法分别测定右房压 (RAP)、肺动脉压 (PAP)、肺毛细血管楔压 (PCWP)和CO ,并计算心脏指数 ,记录心电图。结果 :右室心尖部起搏和室间隔起搏较右房起搏时RAP、PAP升高。心尖部起搏时CO较右房起搏降低 1 9.1 5 % (P <0 .0 1 ) ,室间隔起搏时CO较右房起搏降低 7.86% (P <0 .0 5 ) ,而较心尖部起搏提高 1 2 .2 4 % (P <0 .0 5 )。心尖部起搏和室间隔起搏较右房起搏体表心电图QRS波时限明显延长 ,而室间隔起搏体表心电图QRS波时限比心尖部起搏平均缩短 1 8.6ms(P <0 .0 0 1 )。CO和△QRS波时限的相关性分析表明两者呈负相关关系 (r=- 0 .30 ,P <0 .0 5 )。结论 :起搏体表心电图△QRS波时限与CO呈负相关 ,不同部位起搏对心脏收缩功能的影响不同 ,其中室间隔起搏较心尖部起搏更符合生理性起搏     

不同房室间期对双腔起搏左室收缩功能的影响

为探讨双腔起搏不同房室间期对左室收缩功能的影响及最佳房室间期 ,选择 18例置入DDD起搏器的病窦综合征患者 ,在DOO起搏方式下随机将房室 (AV)间期程控为 10 0 ,130 ,15 0 ,170 ,2 0 0ms,在超声心动图下观察左室收缩功能指标 ,每次测量间隔 5min以上。结果 :AV间期为 15 0ms时左室收缩功能最好 ,与AV间期为 10 0ms时相比 ,左室收缩功能明显改善。以心输出量 (CO)为标准 ,18例中有 9例AV间期在 15 0ms时CO最佳 ,5例在 2 0 0ms时CO最佳 ,3例在 170ms时CO最佳 ,1例在 130ms时CO最佳 ;以CO为标准 ,DOO起搏方式最佳AV间期为 16 6±2 4ms。结论 :双腔起搏的AV间期对左室收缩功能有重要的影响 ,以CO为标准 ,个体化地选择双腔起搏的最佳AV间期对改善患者的心脏功能有重要的意义。     

三腔及双腔心脏起搏器置入术前后的护理

三腔 (右房 右室 冠状窦 )、双腔 (右房 右室 )心脏起搏器是近年来新发展的生理性起搏装置。其主要特点为通过复杂的程控方式保持正常房室收缩顺序 ,根据机体生理改变而自动调节起搏频率 ,具有房室同步功能及频率自适应功能。它能缩短患者的房—室传导时间 ,减轻左室舒张终末期的负荷 ,改善左室功能 ,增加心室排血量。尤其是三腔起搏器不仅具有较好的血液动力学效应 ,而且对治疗房室传导阻滞伴发顽固性、快速型房性心律失常也有明显疗效 ,适应范围广泛。两年来 ,我们已护理安置双腔或三腔生理性永久心脏起搏器患者 5例 ,取得良好效果。现…     

生理性起搏:历史回顾和发展

心脏永久起搏器临床应用60余年,从单腔、双腔、到三腔同步化起搏,从固有频率、按需频率、到频率应答,从心室、心房、到房室顺序起搏,从心尖、间隔、左室、到希浦系统起搏,生理性起搏逐渐被认识、发展和实现.     

探索不用Halo电极射频消融治疗典型心房扑动的方法

目的探讨不用Halo电极消融典型心房扑动(AF)的方法和右心房峡部传导时间间期的意义.方法对9例AF患者进行了心脏电生理检查和射频消融.将普通标测电极分别放置高位右房(A点)、低位右房(B点)、希氏束(C点)、冠状窦(CS34为D点),标测AF发作时右房激动顺序,起搏时和消融后测量右心房峡部传导时间间期(BD、DB). 结果不用Halo电极成功消融9例AF病例.消融后于冠状窦口处起搏时起搏信号至右房下侧壁的时间间期(DB=140.7ms±66.1ms)和右房下侧壁起搏时起搏信号至冠状窦口CS34的时间间期(BD=123.2ms±42.1ms)均较消融前(DB=66.0ms±12.5ms,BD=62.5ms±13.0ms)明显延长,P＜0.01. 结论不用Halo电极能成功消融典型AF,该方法简便、费用低;右心房峡部传导时间间期的定量测定可作为判断峡部完全性双向传导阻滞的方法之一.     

Regional myocardial perfusion during chronic biventricular pacing and after acute change of the pacing mode in patients with congestive heart failure and bundle branch block treated with an atrioventricular sequential biventricular pacemaker

BACKGROUND: Biventricular (BiV) pacing has been found to improve systolic function and exercise tolerance in patients with severe congestive heart failure and bundle branch block. The mechanisms behind this beneficial effect is still not sufficiently clarified. AIM: To evaluate the regional myocardial perfusion (MP) during BiV pacing and after acute change of the pacing mode to conventional dual chamber (DDD) pacing, and single chamber atrial (AAI) pacing in patients with severe congestive heart failure and prolonged QRS width treated with chronic BiV pacing. METHODS AND RESULTS: Fourteen patients (age 63+/-7 years, 13 male) were evaluated 13+/-7 months after implantation of a triple-chamber biventricular pacemaker. MP was quantified with 13N-labeled ammonia positron emission tomography during BiV pacing, DDD pacing, and AAI pacing. MP was assessed in the anterior, lateral, inferior, and septal regions, and the global mean MP was calculated. Clinical assessment was performed before pacemaker implantation and after at least 3 months of BiV pacing including a 6-min walk test (WT), New York Heart Association (NYHA) class functional score and echocardiography. Global mean MP (BiV: 0.65+/-0.20 vs. DDD: 0.65+/-0.21 vs. AAI: 0.65+/-0.18 mlg(-1)min(-1)) and MP in each of the four regions did not differ between the three pacing modes. The patients improved clinically during BiV pacing; 6 min WT increased (338+/-59 vs. 415+/-73 m, P<0.001), NYHA class score improved (class I/II/III/IV: 0/0/11/3 vs. 1/9/2/0, P<0.001), and left ventricular ejection fraction increased (21+/-5 vs. 29+/-8%, P=0.004). CONCLUSION: No differences in regional MP are detectable after chronic BiV pacing when the pacing mode is changed acutely in patients with severe congestive heart failure and bundle branch block. This finding indicates, that the clinical improvement caused by BiV pacing is not associated with any increase in the MP and thereby oxygen demand.     

Single chamber ventricular compared with dual chamber pacing: a review

Since its introduction in the 1950s, the cardiac pacemaker has become increasingly sophisticated in an attempt to mimic normal cardiac physiology. Rapidly evolving pacing technology has seen pacemakers evolve from crude, fixed-rate, single chamber ventricular devices to dual chamber rate-adaptive units. While there is indirect evidence that supports the use of dual chamber pacing in the vast majority of patients, it is still unclear whether these newer, more expensive devices afford a significant morbidity and mortality benefit over single-chamber, ventricular, rate-adaptive pacemakers. A review of three large, randomized trials failed to demonstrate a clear benefit of dual chamber or atrial-based pacing over single chamber ventricular pacing for the majority of cardiovascular outcomes (heart failure, stroke and mortality), with the possible exception of atrial fibrillation. Information is also needed on the potential protective effects of atrial-based pacing over dual chamber pacing in elderly patients with sinus node dysfunction. Longer follow-up periods may be necessary to determine whether there are any mortality benefits associated with dual chamber pacing. Additional confirmation of benefits of dual chamber pacing may be provided by other ongoing prospective trials.     

Dual chamber pacing in the treatment of congestive heart failure

The present work reviews current literature and the authors' experience of dual chamber pacing in the treatment of patients with congestive heart failure (CHF). In these patients, the atrial contribution to ventricular filling may be less than optimal, especially in the presence of first degree atrioventricular block or mitral insufficiency, both of which are common in the elderly subject with CHF. Dual chamber pacing with short atrioventricular delays has proved effective in enhancing ventricular filling and, in selected cases, cardiac output, with improvement in clinical and instrumental parameters of heart failure. However, for an appropriate atrioventricular synchronization of the left chambers during pacing, the interatrial conduction time must be considered, to avoid atrial contraction against a closed mitral valve. Thus, dual chamber pacing may be a treatment option for CHF that fails to respond to medical therapy.     

Physiological cardiac pacing: Current status

Adverse hemodynamics of right ventricular (RV) pacing is a well-known fact. It was believed to be the result of atrio-ventricular (AV) dyssynchrony and sequential pacing of the atrium and ventricle may solve these problems. However, despite maintenance of AV synchrony, the dual chamber pacemakers in different trials have failed to show its superiority over single chamber RV apical pacing in terms of death, progression of heart failure, and atrial fibrillation (AF). As a consequence, investigators searched for alternate pacing sites with a more physiological activation pattern and better hemodynamics. Direct His bundle pacing and Para-Hisian pacing are the most physiological ventricular pacing sites. But, this is technically difficult. Ventricular septal pacing compared to apical pacing results in a shorter electrical activation delay and consequently less mechanical dyssynchrony. But, the study results are heterogeneous. Selective site atria pacing (atrial septal) is useful for patients with atrial conduction disorders in prevention of AF.     

Long-term transvenous AV-sequential pacing in a failing atriopulmonary Fontan patient

We report on a 32-year-old man with tricuspid atresia, pulmonary stenosis and hypoplastic right ventricle. He had received a Fontan-Kreutzer procedure (anastomosis between the right atrial appendage and the pulmonary artery) at the age of 14 years. At the age of 2 years, an abdominal VVI-pacemaker with an epicardial ventricular lead had been implanted because of symptomatic third degree AV-block. The patient was now hospitalized with symptoms of severe congestive heart failure. A least invasive approach restoration of AV-synchrony by a dual chamber pacer was performed. Therefore a complete transvenous approach to avoid thoracotomy was attempted. A specially designed CS lead was advanced via the CS to a left lateral ventricular vein for ventricular stimulation. After institution of dual chamber pacing the patient recovered of his heart failure. During a follow-up time of 20 months the patient was clinically stable in the AV-sequential pacing. Conclusion: Dual chamber pacing using a transvenously placed coronary sinus lead for ventricular stimulation may improve congestive heart failure in patients after the classic Fontan operation. The minimally invasive transvenous approach might be the best solution for patients who need a pacemaker and are not candidates for surgery or heart transplantation.     

双心室起搏的临床疗效观察

目的　探讨缺血性或扩张型心肌病合并充血性心力衰竭行永久性双心室起搏治疗的临床效果。方法　对 1 0例缺血性或扩张型心肌病合并难治性心力衰竭和左束支阻滞患者 ,常规植入右心室起搏导线的同时植入冠状静脉窦电极导线于左室侧静脉、心大或心中静脉 ,行双心室同步起搏 (其中 2例为四腔起搏 )。通过临床观察、超声心动图测定及 6分钟平地行走评定对心功能的影响。结果　在充血性心力衰竭合并左束支阻滞患者植入冠状静脉窦电极导线行双心室起搏 ,产生较窄 QRS波 ,临床心功能从 ～ 级提高至 ～ 级 ( NYHA) ,同时使二尖瓣返流减少 ,射血分数提高 ,左室舒张末期内径缩小 ,6分钟平地行走距离比术前明显提高。结论　双心室起搏对难治性心力衰竭可能有辅助治疗作用。     

双心室起搏的初步临床经验

目的 探讨缺血性或扩张型心肌病合并充血性心力衰竭行永久性双心室起搏治疗的临床效果。方法 对５例缺血性或扩张型心肌病合并难治性心力衰竭和左束支阻滞患者常规植入右心室起搏导线的同时植入冠状静脉窦导线于心大静脉或心中静脉，分别行右心室心尖部起搏及双心室起搏，应用Ｓｗａｎ－Ｇａｎｚ导管或超声心动图测定不同起搏地心功能的影响。结果 在充血性心力衰竭合并左束支阻滞患者植入冠状静脉窦导经至心大静脉或心中静脉行以     

The Managed Ventricular pacing versus VVI 40 Pacing (MVP) Trial: clinical background, rationale, design, and implementation

Background: Implantable cardioverter defibrillators (ICDs) reduce mortality among appropriately selected patients who have had or are at risk for life‐threatening ventricular arrhythmia. Right ventricular apical (RVA) pacing has been implicated in worsening heart failure and death. The optimal pacemaker mode for bradycardia support while minimizing unnecessary and potentially harmful RVA pacing has not been determined. Methods: The Managed Ventricular pacing vs. VVI 40 Pacing Trial (MVP) is a prospective, multicenter, randomized, single‐blind, parallel, controlled clinical trial designed to establish whether atrial‐based dual‐chamber managed ventricular pacing mode (MVP?) is equivalent or superior to back‐up only ventricular pacing (VVI 40) among patients with standard indications for ICD therapy and no indication for bradycardia pacing. The MVP Trial is designed with 80% power to detect a 10% reduction in the primary endpoint of new or worsening heart failure or all‐cause mortality in the MVP?‐treated group. Approximately 1,000 patients at 80 centers in the United States, Canada, Western Europe, and Israel will be randomized to MVP? or VVI 40 pacing after successful implantation of a dual‐chamber ICD. Heart failure therapies will be optimized in accordance with evidence‐based guidelines. Prespecified secondary endpoints will include ventricular arrhythmias, atrial fibrillation, new indication for bradycardia pacing, health‐related quality of life, and cost effectiveness. Enrollment began in October 2004 and concluded in April 2006. The study will be terminated upon recommendation of the Data Monitoring Committee or when the last patient enrolled and surviving has reached a minimum 2 years of follow‐up. Conclusion: The MVP Trial will meet the clinical need for carefully designed prospective studies to define the benefits of atrial‐based dual‐chamber minimal ventricular pacing versus single‐chamber ventricular pacing in conventional ICD patients.     

快速右室起搏建立动物心力衰竭模型

为建立稳定的慢性终末期心力衰竭 (简称心衰 )动物模型 ,选择太湖梅山猪 12只 ,采用快速 (2 30次 /分 )右室起搏 4周 ,之后改用 190次 /分的频率维持右室起搏 4周。并应用超声心动图及心导管检查 ,观察猪在实验的不同阶段心功能参数。结果 :快速起搏 4周后 ,所有猪均出现明显的充血性心衰的表现 ;超声心动图显示心室壁变薄、射血分数、心输出量明显下降 ;心导管检查结果示肺动脉压、右房压、肺动脉楔压升高 ,而心输出量、每搏输出量和动脉压降低 ;在以 190次 /分维持 4周后 ,上述参数仍保持稳定。结论 :快速右室起搏可建立稳定、持久的慢性终末期心衰模型。