右心室流出道间隔部起搏和右心室心尖部起搏的对比研究

目的:对比研究主动电极右心室流出道间隔部(RVOTS)起搏与被动电极右心室心尖部起搏的可行性与安全性及对远期心功能的影响。方法:需要安置体内埋藏式心脏起搏器的患者62例,随机分为两组,30例用螺旋电极行RVOTS起搏(主动电极组),32例用被动电极行右心室心尖部起搏(被动电极组);记录两组术中及术后的各项参数,并随访6个月。观察两组远期心功能各项指标,并进行比较。结果:两组均顺利完成手术。两组患者起搏器植入即刻参数比较:与被动电极组比较,主动电极组导线阻抗减小,差异有统计学意义(P0.01);主动电极组植入时间和曝光时间较被动电极组偏长,差异有统计学意义(P0.01和P0.05)。两组患者均没有出现电极穿孔致心包压塞的并发症、电极导线脱位、囊袋感染和严重心脏事件。随访6个月两组各参数比较:与被动电极组比较,主动电极组QRS波时限、左心室重量均下降、NYHA心功能分级改善(P0.01或P0.05),左心室射血分数、左室短轴缩短率、6min步行试验均增加(P0.01或P0.05),差异均有统计学意义;两组均未发生严重心脏事件。结论:使用主动(螺旋)电极行RVOTS起搏不但安全可靠,而且可改善患者远期心功能,提高其生存质量。     

Upgrading Pacemaker Patients with Right Ventricular Apical Pacing to Right Ventricular Septal Pacing Improves Left Ventricular Performance and Functional Capacity

Background : Right ventricular (RV) apical pacing results in abnormal left ventricular (LV) electrical and mechanical activation and is associated with an increased risk of developing heart failure. Chronic RV septal pacing has been shown to be superior to RV apical pacing in newly implanted patients. However, whether RV septal pacing can reverse deleterious effects of RV apical pacing remain unclear.
Methods : We evaluated the effects of RV septal pacing on LV performance and functional capacity before and at 18 months after device replacement in 12 patients with previously permanent RV apical pacing and in 12 control patients that continued RV apical pacing. All patients underwent radionuclide ventriculography and 6-minute hallwalk (6-MHW) test before replacement (baseline) and at 18 months afterward to determine changes in LV performance and functional capacity, respectively.
Results : After RV septal upgraded, there was a significant decrease in paced QRS duration (171.2 ± 3.9 ms to 160.4 ± 3.5 ms, P = 0.0016), increase in LV ejection fraction (55.2 ± 2.6% vs 60.4 ± 2.9%, P = 0.0002), the peak ventricular filling rate (2.60 ± 0.13 s⁻¹ vs 3.01 ± 0.14 s⁻¹, P = 0.046), and 6-MHW (308.2 ± 31.6 m vs 355.5 ± 34.2 m, P = 0.015) at 18 months compared with baseline. No changes in these parameters were observed in the control group (P > 0.05).
Conclusion : RV septal pacing upgraded improves LV systolic and diastolic function and functional capacity in patients with previously permanent RV apical pacing. These findings suggest that RV septal pacing can reverse the deleterious effects of RV apical pacing in patients who required permanent ventricular pacing.     

Advances in Cardiac Pacing: Beyond the Transvenous Right Ventricular Apical Lead

While for decades right ventricular (RV) apical pacing has been the standard of care for patients requiring pacemaker or defibrillator lead placement, investigators have sought alternatives to achieve more physiologic electrical activation of the heart and reduce long‐term pathologic effects of nonphysiologic apical pacing. These investigations have included attempts at identifying superior pacing sites within the right atrium and RV and development of new leads to enhance specificity of sensing and capture. This review focuses on recent advances in alternative sites for pacing and developments in novel pacing technology ranging from intramyocardial electrodes to leadless pacemakers. First, there have been several studies demonstrating potential benefits of site‐specific pacing, including His bundle pacing and RV outflow tract pacing in potentially attenuating electromechanical dyssynchrony and long‐term functional decline seen with RV apical pacing. Available options for lead placement have been enhanced by development of intramyocardial electrodes that may significantly reduce far‐field oversensing and nonchamber specific capture. With development of intramyocardial electrodes, the potential for atrioventricular septal pacing has recently been described, making synchronous activation of both ventricles with a one‐lead system possible without crossing the tricuspid valve and offering an alternative to modern cardiac resynchronization therapy (CRT). Finally, recent advances in leadless pacemaker systems using ultrasound or magnetic fields are briefly discussed. The results of these studies suggest that there may be options to the RV apex, made possible by novel lead and pacemaker technology. These advances can potentially aid in reducing long‐term negative effects of chronic pacemaker therapy.     

Right Ventricular Versus Biventricular Pacing for Heart Failure and Atrioventricular Block

The use of cardiac resynchronization therapy (CRT) is well accepted as an important option for the treatment of patients with systolic heart failure and prolonged QRS duration. CRT for patients with narrow QRS complexes is reserved for patients who are undergoing implantation of new or replacement pacemakers or implantable cardioverter defibrillators with an anticipated significant requirement for ventricular pacing. The Biventricular versus Right Ventricular Pacing in Heart Failure Patients with Atrioventricular Block (BLOCK HF) Trial examined the role of CRT in heart failure patients with atrioventricular block and demonstrated significantly better outcomes with CRT compared to right ventricular pacing. On the other hand, conflicting preliminary data were reported by the Biventricular Pacing for Atrioventricular Block to Prevent Cardiac Desynchronization (BioPace) Trial investigators. In this review, we will discuss the adverse consequences of chronic right ventricular pacing, the options of alternate pacing sites in the right ventricle versus biventricular pacing, and the findings from the BLOCK HF Trial as well as the preliminary data from the BioPace Trial. Our goal is to explore the role of biventricular pacing in patients with atrioventricular block.     

Dilated Cardiomyopathy After Long-Term Right Ventricular Apical Pacing in Children With Complete Atrioventricular Block: Role of Setting of Ventricular Pacing

BackgroundPediatric patients paced for complete atrioventricular block (CAVB) are at risk of developing dilated cardiomyopathy (DCM). We sought to explore the role played by the setting of ventricular pacing.Methods and ResultsA total of 35 patients <18 years of age at diagnosis were enrolled. Twenty-eight (80%) received pacemakers after a mean follow-up of 10 years, and most were paced from right ventricular (RV) apex (n = 23). None of the 7 patients without pacemakers developed DCM, whereas 8 (35%) paced from RV apex had DCM 2.6 ± 2.2 years after pacing. The percentage of ventricular pacing was >90% in all patients. Multivariate analysis revealed that the cumulative Z score of lower ventricular rate setting was the single most important risk factor for DCM (HR, 3.14; 95% CI, 1.07-9.19; P = .037). Subgroup analysis in patients with VVI/VVIR modes revealed an even stronger predictive value of the cumulative Z score of lower ventricular rate setting (HR, 9.12; 95% CI, 1.53-54.24; P = .015).ConclusionsHigher setting of the lower ventricular rate, though still within the age-appropriate range, was associated with increased risk of developing DCM in pediatric patients with CAVB and chronic RV apical pacing.     

Intramural Dyssynchrony from Acute Right Ventricular Apical Pacing in Human Subjects with Normal Left Ventricular Function

Ventricular pacing causes early myocardial shortening at the pacing site and pre-stretch at the opposing ventricular wall. This contraction pattern is energetically inefficient and may lead to decreased cardiac function. This study was designed to describe the acute effects of right ventricular apical (RV_a) pacing on dyssynchrony and systolic function in human subjects with normal left ventricular (LV) function and compare these effects to pacing from alternate ventricular sites. Patients (n = 26) undergoing an electrophysiology evaluation were studied during atrial pacing (AAI) and dual chamber pacing from the RV_a, left ventricular free wall (LV_fw), and the combination of RV_a and LV_fw (BiV). Tissue Doppler imaging was used to measure intramural dyssynchrony by utilizing an integrated cross-correlation synchrony index (CCSI) from the apical 4-chamber view. RV_a and BiV pacing significantly reduced systolic function as measured by longitudinal systolic contraction amplitude (SCA_long) (p < 0.05) and LV velocity time integral (VTI) (p < 0.05) compared to AAI and LV_fw pacing. RV_a (and to a lesser extent BiV) pacing resulted in septal and lateral intramural dyssynchrony as indicated by significantly (p < 0.05) lower CCSI values as compared to AAI. CCSI was significantly (p < 0.05) worse during RV_a than LV_fw pacing. In patients with normal LV function, acute ventricular pacing in the RV_a alone, or in conjunction with LV_fw pacing (BiV), results in impaired regional and global LV systolic function and intramural dyssynchrony as compared to LV_fw pacing alone.     

右心室间隔部起搏的核素心室显像位相分析及心电图研究

目的 :观察右心室间隔部 (RVS)起搏时的心室激动顺序和双心室同步性 ;评估在接受心室起搏的患者中心电图的演变。　　方法 :慢性心房颤动伴长RR间歇或缓慢心室率需植入永久起搏器患者 10例 ,男性 7例 ,女性 3例 ,平均年龄(64 2 0± 12 61)岁 ,均采用抑制型按需心室起搏 (VVI)模式先后顺序进行右心室心尖部 (RVA)和RVS。记录术前心电图、术中RVA和RVS起搏心电图 ;术后进行核素心室显像位相分析 ,对比自身心律与RVA和RVS起搏时心室激动顺序和双心室同步性的差异。　　结果 :核素心室显像位相分析证实RVA起搏造成心室激动顺序异常和双心室失同步 ;RVS起搏时心室激动顺序、双心室同步性与正常基本一致。RVA起搏时QRS波群较术前自身增宽 [(173 0 0± 14 94)msvs (74 5 0± 7 62 )ms ,P <0 0 0 1] ,差异有非常显著性 ;RVS起搏的QRS波群宽度较RVA起搏缩窄 [(13 6 0 0± 13 5 0 )msvs (173 0 0± 14 94)ms ,P <0 0 0 1) ] ,差异有非常显著性。　　结论 :RVS起搏时心室激动顺序、双心室同步性与正常基本一致 ;与RVA起搏相比RVS起搏时心电轴、QRS波群与正常心电图相似或接近。     

右心室流出道起搏

近来有越来越多的证据表明传统的右室心尖部起搏对心脏有着不利的影响,用其他部位来替代心尖起搏已经成为研究的热点,其中研究最多的是右室流出道起搏。现综述右室流出道起搏的优点和右室流出道的解剖结构及具体起搏部位,电极的定位方法等,以期为今后的临床工作提供一点帮助,     

Left Atrial Responses to Acute Right Ventricular Apical Pacing in Patients with Sick Sinus Syndrome

Chronic right ventricular apical (RVA) pacing can lead to an increased risk of heart failure and atrial fibrillation, but the acute effects of RVA pacing on left atrial (LA) function are not well known. Twenty‐four patients with sick sinus syndrome and intact intrinsic atrioventricular conduction were included. All patients received dual‐chamber pacemaker implants with the atrial lead in the right atrial appendage and the ventricular lead in the right ventricular (RV) apex. Transthoracic standard and strain echocardiography (measured by tissue Doppler imaging and speckle tracking image) were performed to identify functional changes in the left ventricle (LV) and LA before and after 1 hour of RVA pacing. The LA volume index did not change after pacing; however, the ratio of peak early diastolic mitral flow velocity (E) to peak early diastolic mitral annular velocity (Ea) was significantly increased and peak systolic LA strain (Sm), mean peak systolic LA strain rate (SmSR), peak early diastolic LA strain rate (EmSR), and peak late diastolic LA strain rate (AmSR) were significantly reduced after RV pacing. LV dyssynchrony, induced by RV pacing, had a significant correlation with E/Ea, Sm, and SmSR after pacing. E/Ea also had a negative correlation with Sm and SmSR after pacing. Multivariate regression analysis identified LV dyssynchrony and E/Ea as important factors that affect Sm, SmSR, EmSR, and AmSR after acute RVA pacing. Acute RVA pacing results in LA functional change and LV dyssynchrony and higher LV filling pressures reflected by E/Ea are important causes of LA dysfunction after acute RVA pacing.     

小儿右室流出道起搏

对于一些需要安装永久起搏器的患者来讲,由于易于固定,起搏阈值低等优点,右心室起搏常将起搏电极置于心尖部,但长期随访发现,心尖部起搏可改变心室激动顺序,导致心室收缩不同步,造成二尖瓣反流、心房颤动和心功能不全。研究发现右室流出道起搏对左室功能的保护较右室心尖部起搏有利,由于右室流出道起搏靠近His束,电活动近似正常生理状态,可使左右心室电-机械活动更协调,从而抑制心室重构并保护心功能,因此,右室流出道起搏是替代右室心尖部起搏的较好选择。     

右室起搏部位研究进展

起搏器植入以来,右室心尖部起搏一直为传统起搏位置,随着对其研究的深入,寻找更佳的起搏位点,成为人们研究的热点.新的起搏部位研究主要集中在右室流出道、右室中位间隔、右室流人道、直接希式束、希式束旁及心室双部位起搏,现对上述几种起搏部位的电极固定位置、及其对心电、机械活动及对心功能影响等方面进行综述.     

右室双部位起搏的临床应用

右室双部位起搏是一种阃接的双室起搏技术，操作简单，不增加安置术的风险，同时可以使心室再同步变为可能，增加心肌收缩力，改善心功能，具有较好的临床应用价值。     

Large Apical Muscular Ventricular Septal Defect: Asymptomatic due to Anomalous Muscle Bundles in the Right Ventricle

This case report demonstrated an apical muscular ventricular septal defect (VSD) that was a large defect but behaved like a small defect because of the restrictive flow across the anomalous muscle bundles in the right ventricular (RV) apex. The anomalous muscle bundles separated the RV sinus into two parts: the RV apex connecting with the left ventricle through the apical muscular VSD on one side, and the rest of the RV sinus connecting with RV inflow and RV outflow on the other side. These findings explained why the 11-year-old girl in this study remained asymptomatic without evidence of volume load. Thus far, it was not necessary to close her defect because of the hemodynamic insignificance.     

Clinical Outcomes of His Bundle Pacing Compared to Right Ventricular Pacing

Background

Right ventricular pacing (RVP) is associated with heart failure and increased mortality. His bundle pacing (HBP) is a physiological alternative to RVP.