Long‐Term Mechanical Consequences of Permanent Right Ventricular Pacing: Effect of Pacing Site

Optimal Right Ventricular Pacing Introduction: Long‐term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long‐term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function. Methods: Fifty‐eight patients who were prospectively randomized to long‐term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18‐segment time‐to‐peak longitudinal systolic strain and 12‐segment time‐to‐peak systolic tissue velocity. Intra‐LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time‐to‐onset of systolic flow in the RVOT and LV outflow tract. Septal A’ was measured using tissue velocity images. Results: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end‐systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT‐paced group over the RVA‐paced patients. RVA‐pacing was associated with greater interventricular mechanical dyssynchrony and intra‐LV dyssynchrony than RVOT‐pacing. Septal A’ was adversely affected by intra‐LV dyssynchrony (P < 0.05). Conclusions: Long‐term RVOT‐pacing was associated with superior indices of LV structure and function compared with RVA‐pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1120‐1126)     

右室流出道起搏现状

右室心尖部作为传统的永久心脏起搏器植入位点,主要是因为电极容易放置及电极脱位率低。但是心尖部起搏属非生理性起搏,它使心室除极和机械收缩发生异常,从而导致长期的血流动力学紊乱(心室收缩和舒张异常)和组织结构的改变。随着近年主动固定的螺旋电极及螺旋电极操作手柄的问世,使右室流出道起搏成为可能。大量动物实验和临床研究提示右室流出道靠近房室结、希氏束部位,在此部位起搏心室激动和收缩顺序趋于正常,从而能明显的改善血流动力学指标。目前右室流出道起搏尚处于临床实验阶段,且关于右室流出道解剖位点的确定,适宜患者群的筛选标准、监测和评价指标的选择尚无统一的标准。其长期效果及能否改善患者预后等还有待更深入的研究。现就目前国内外关于右室流出道起搏的研究现状综述如下。     

Chronic Effect of Right Ventricular Pacing on Left Ventricular Rotational Synchrony in Patients with Complete Atrioventricular Block

Background: Chronic effect of right ventricular (RV) pacing on left ventricular (LV) rotational synchrony is unknown. The aim of this study is to assess chronic effect of RV pacing on LV rotational synchrony using two‐dimensional ultrasound speckle tracking imaging. Methods and Results: Thirty‐one patients who underwent dual‐chamber pacemaker implantation for complete atrioventricular block, and age‐ and sex‐matched 10 healthy controls were assessed. We divided our patients into RV apical (RVA, n = 16) and RV outflow tract (RVOT, n = 15) pacing groups. We compared echocardiographic parameters such as LV rotational synchrony between pacing groups and healthy control. We defined Q to peak rotation interval as the interval from the beginning of the Q‐wave to the peak apical counter‐clockwise or peak basal clockwise rotation. We calculated apical–basal rotation delay by subtracting basal Q to peak rotation interval from apical one as the representative of rotational synchronization. Apical–basal rotation delay of RVA pacing was significantly longer than that of healthy control (100 ± 110 vs. ?6 ± 15 ms, P = 0.002), while there was no statistically significant difference between RVOT pacing and healthy control (?3 ± 99 vs. ?6 ± 15 ms, P = 0.919). Conclusions: LV rotation during RVOT pacing is synchronous at 15 months after pacemaker implantation, while RVA pacing provokes LV rotational dyssynchrony by inducing delayed apical rotation at 7 years after pacemaker implantation in patients with complete atrioventricular block. (Echocardiography 2011;28:69‐75)     

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)%,...     

Right ventricular outflow versus apical pacing in pacemaker patients with congestive heart failure and atrial fibrillation

INTRODUCTION: Prior studies suggest that right ventricular apical (RVA) pacing has deleterious effects. Whether the right ventricular outflow tract (RVOT) is a more optimal site for permanent pacing in patients with congestive heart failure (CHF) has not been established. METHODS AND RESULTS: We conducted a randomized, cross-over trial to determine whether quality of life (QOL) is better after 3 months of RVOT than RVA pacing in 103 pacemaker recipients with CHF, left ventricular (LV) systolic dysfunction (LV ejection fraction < or = 40%), and chronic atrial fibrillation (AF). An additional aim was to compare dual-site (RVOT + RVA, 31-ms delay) with single-site RVA and RVOT pacing. QRS duration was shorter during RVOT (167 +/- 45 ms) and dual-site (149 +/- 19 ms) than RVA pacing (180 +/- 58 ms, P < 0.0001). At 6 months, the RVOT group had higher (P = 0.01) role-emotional QOL subscale scores than the RVA group. At 9 months, there were no significant differences in QOL scores between RVOT and RVA groups. Comparing RVOT to RVA pacing within the same patient, mental health subscale scores were better (P = 0.03) during RVOT pacing. After 9 months of follow-up, LVEF was higher (P = 0.04) in those assigned to RVA rather than RVOT pacing between months 6 and 9. After 3 months of dual-site RV pacing, physical functioning was worse (P = 0.04) than during RVA pacing, mental health was worse (P = 0.02) than during RVOT pacing, and New York Heart Association (NYHA) functional class was slightly better (P = 0.03) than during RVOT pacing. There were no other significant differences between RVA, RVOT and dual-site RV pacing in QOL scores, NYHA class, distance walked in 6 minutes, LV ejection fraction, or mitral regurgitation. CONCLUSION: In patients with CHF, LV dysfunction, and chronic AF, RVOT and dual-site RV pacing shorten QRS duration but after 3 months do not consistently improve QOL or other clinical outcomes compared with RVA pacing.     

右室双部位起搏与双室同步起搏的急性血液动力学对比研究

比较右室双部位 (RV Bi)起搏和双室 (BiV)同步起搏对血液动力学的影响 ,并与右室心尖部 (RVA)、右室流出道 (RVOT)、左室基底部 (LVB)起搏相比较 ,明确双部位起搏是否优于单部位起搏。 15例患者中病窦综合征 8例、Ⅲ度房室阻滞 7例。分别行RVA、RVOT、LVB、RV Bi、BiV起搏 (VVI,6 0～ 90次 /分 ) ,测定心输出量 (CO)和心脏指数(CI)、肺毛细血管嵌顿压 (PCWP)和QRS波时限 (QRSd)。结果 :①与RVA起搏相比 ,RVOT、LVB、RV Bi、BiV起搏CI分别增加了 7.5 %、11.3%、15 .5 %和 17.2 % ,PCWP分别降低了 14.9%、10 .3%、2 1.7%和 2 0 .0 % (P均 <0 .0 1)。②RV Bi、BiV起搏较RVOT、LVB起搏的CO、CI增高而PCWP降低 (P均 <0 .0 5 )。③RV Bi与BiV起搏、RVOT与LVB起搏之间CO、CI和PCWP无显著差异。④RVOT、RV Bi、BiV起搏的QRSd(分别为 12 8± 11,111± 16 ,10 3± 13ms)较RVA起搏 (146± 18ms)时显著缩短 (P≤ 0 .0 0 1) ,而LVB起搏 (142± 15ms)与RVOT、RVA起搏时无显著差异。结论 :RV Bi起搏和BiV同步起搏的急性血液动力学效果无明显差异 ,但双部位起搏的效果明显优于单部位起搏 ;双部位起搏的QRSd也比单部位起搏明显缩短     

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。     

Right ventricular apex versus right ventricular outflow tract pacing: prospective, randomised, long-term clinical and echocardiographic evaluation

INTRODUCTION: In patients treated with permanent pacing, the electrode is typically placed in the right ventricular apex (RVA). Published data indicate that such electrode placement leads to an unfavourable ventricular depolarization pattern, while right ventricular outflow tract (RVOT) pacing seems to be more physiological. AIM: To compare long-term effects of RVOT versus RVA pacing on clinical status, left ventricular (LV) function, and the degree of atrioventricular valve regurgitation. METHODS: Patients with indications for permanent pacing, admitted to hospital between 1996 and 1997, were randomised to receive RVA or RVOT pacing. In 2004 during a final control visit in 27 patients clinical status, echocardiographic parameters and QRS complex duration as well as NT-proBNP level were measured. Analysed parameters were compared between groups and in the case of data available during the perioperative period also their evolution in time was assessed. RESULTS: Out of 27 patients 14 were randomised to the RVA group and 13 to the RVOT group. No significant differences between groups were observed before the procedure with respect to age, gender, comorbidities or echocardiographic parameters. Mean duration of pacing did not differ significantly between the groups (89+/-9 months in RVA group vs 93+/-6 months in RVOT group, NS). In the RVA group significant LV ejection fraction decrease was observed (from 56+/-11% to 47+/-8%, p <0.05); in the RVOT group LV ejection fraction did not change (54+/-7% and 53+/-9%; NS). Progression of tricuspid valve regurgitation was also observed in the RVA group but not in the RVOT group. During the final visit NT-proBNP level was significantly higher in the RVA group: 1034+/-852 pg/ml vs 429+/-430 pg/ml (p <0.05). CONCLUSIONS: In patients with normal LV function permanent RVA pacing leads to LV systolic and diastolic function deterioration. RVOT pacing can reduce the unfavourable effect and can slow down cardiac remodelling caused by permanent RV pacing. Clinical and echocardiographic benefits observed in the RVOT group after 7 years of pacing are reflected by lower NT-proBNP levels in this group of patients.     

右心室不同部位起搏对左心室收缩功能的影响

目的:比较右心室心尖(RVA)及流出道间隔部(RVOT-S)起搏对左心室收缩功能的影响,探讨合理的右心室起搏部位。方法:自2007年8月~2009年12月,36例左室收缩功能正常的完全性房室传导阻滞患者,随机纳入RVA和RVOT-S起搏组,起搏器植入12月后分别测定左室射血分数(LVEF),左室收缩末容量(LVESV),主动脉瓣口速度时间积分(VTI),主动脉与肺动脉瓣开放时间差(QAO-QP),房颤负荷(AFb),自动模式转换(AMS),血浆脑钠尿肽原(NT-proBNP)变化,QRS波宽度,比较两组的差别。结果:起搏12月后RVOT-S组LVEF及VTI明显高于RVA组(均P<0.05);LVESV,QAO-QP,NT-BNP,AFb,AMS及QRS波宽度明显低于RVA组(均P<0.05)。结论:与RVOT-S组相比,RVA长期起搏可导致明显左右心室间以及左室内收缩不同步及左室重构,减低左心室收缩功能,对心室依赖起搏患者应首选RVOT-S为心室电极植入部位。     

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。     

Acute Changes in Cardiac Synchrony and Output According to RV Pacing Sites in Koreans with Normal Cardiac Function

Introduction: The synchrony of the pacing heart can be affected by the right ventricular (RV) pacing site and is crucial to cardiac function in pacemaker recipients. We evaluated the acute changes in cardiac synchrony according to the RV pacing sites in normal systolic functioning subjects with normal QRS. Methods: We conducted this study with 30 patients with the pacing in the RV apex (RVA), RV septum (RVS), and RV outflow tract (RVOT) in a sequential manner . Transthoracic echocardiography was conducted at rest and during pacing in order to measure interventricular and intraventricular dyssynchrony in all patients. Results: QRS duration (148.1 ± 12.8 ms) of RVA pacing was significantly shorter than that of RVS pacing (154.4 ± 14.1 ms, P < 0.01) and RVOT pacing (160.6 ± 15.7 ms, P < 0.001). We noted no statistically significant difference in cardiac output according to the pacing sites. The interventricular dyssynchrony with M-mode and Doppler echocardiography in RVOT pacing was increased to an insignificant degree as compared with those with RVS pacing or RVA pacing. The intraventricular dyssynchrony with tissue Doppler echocardiography in RVA pacing was reduced significantly as compared with that of RVS pacing or RVOT (RVA = 60.3 ± 32.7 ms, RVS = 82.1 ± 33.8 ms, RVOT = 79.1 ± 33.3 ms; RVA vs RVS = P < 0.05, RVA vs RVOT = P < 0.01, RVS vs RVOT = P = NS). Conclusion: RVA pacing is superior to RVS and RVOT pacing with regard to intraventricular synchrony in normal systolic functioning subjects with normal QRS. Cardiac output at RVA pacing is not inferior to other sites.     

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.     

右心室心脏起搏升级双心室起搏的临床应用进展

心脏再同步化治疗是一项成熟应用于临床进展期心力衰竭合并左心收缩功能不全,心脏失同步患者治疗方法。右心室心尖部起搏改变了正常心脏的激动收缩顺序从而导致心脏电机械失同步,心脏收缩功能下降最终发生心力衰竭。适时地将起搏患者右心室起搏系统升级为双心室起搏可以纠正右室起搏导致的心脏失同步,最大限度保持左、右双心室间正常的电激动顺序和收缩同步性,有效地避免了起搏对血流动力学和心功能的不良影响。近来短期研究发现这种起搏系统升级可明显改善心脏活动的同步性,从而改善心功能、提高生活质量。文章综述了右室心尖部起搏的病理生理及升级右室起搏到双室起搏治疗的相关临床试验、显效机制及存在的问题。     

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。     

右心腔不同部位起搏的慢性血流动力学对比研究

比较右心耳 (RAA)、右室流出道 (RVOT)与右室心尖部 (RVA)起搏的慢性血流动力学效果 ,评价RVOT起搏的可行性。2 9例患者 ,9例RAA起搏、8例RVOT起搏、12例RVA起搏 ,分别在术前及术后 6 .11± 4 .0 1、5 .38± 2 .92、5 .5 0± 2 .88个月 ,用多普勒超声心动图观察右心腔不同部位起搏的慢性血流动力学参数 ,包括左室射血分数(LVEF)、左室内径缩短分数 (SF)、肺动脉瓣口峰值血流速度 (PV)、二尖瓣口E峰血流速度 (E)、A峰血流速度 (A)及比值 (E/A)。结果 :RAA起搏时 ,LVEF、SF分别下降为 4 .5 6 %± 3.71% ,3.33%± 2 .83% ,P <0 .0 5。RVOT起搏时 ,LVEF、SF、E/A分别下降为 6 .38%± 4 .6 9% ,4 .13%± 2 .75 % ,1.2 9± 0 .5 1,P <0 .0 1。RVA起搏时 ,LVEF、SF、PV、E、E/A分别下降为 1.4 2 %± 5 .32 % ,7.92 %± 3.96 % ,8.5 8± 11.33cm/s,8.17± 9.6 3cm/s,0 .2 7± 0 .2 9,P <0 .0 1或0 .0 5。A则上升为 7.91± 11.2 6cm/s(P <0 .0 5 )。RVOT起搏与RVA起搏相比LVEF、SF明显改善 (P均 <0 .0 5 ) ,且临床症状明显减轻 ;与右房起搏相比 ,E/A下降 (P <0 .0 5 ) ,其他指标在随访期内未显示出统计学意义上的差别。结论 :对于心功能较好的患者 ,右心腔不同部位起搏对慢性血流动力学均有一定程度的负面影响 ;R     

Acute mechanical effect of right ventricular pacing at different sites using velocity vector imaging

Objective: Velocity vector imaging (VVI) allows noninvasive measurement of left ventricular (LV) strain and rotation angle‐independently. We investigated strain, rotation and myocardial synchrony when pacing at different sites in the right ventricle to determine which site yields the most physiological pacing, as determined with VVI imaging. Method: Thirty‐one patients with normal LV function referred for elective electrophysiology exam were used in this study. Catheters (6F quadripolar) were positioned in the right atrium, right ventricular apex, right ventricular outflow tract, and His bundle after electrophysiology exam was done. Regional and global LV circumferential strain (CS), radial strain (RS), and LV rotation of LV short‐axis measurements were obtained. Two dyssynchrony parameters (AS‐P delay and SDt_6S) of CS and RS were obtained. Compare these values among each pacing, respectively. Result: CS, RS, and twist, which represent the LV systolic function, were significantly reduced in RVOT pacing and RVA pacing than RA pacing. Two dyssynchrony parameters (AS‐P delay and SDt_6S) were significantly longer in response to RVOT or RVA pacing compared to RA pacing. No significant differences were found between RVOT pacing and RVA pacing. CS and RS were obviously reduced in the regions surrounding the pacing site. There was no significant difference in CS, RS, twist, and mechanical dyssynchrony parameters when comparing His and RA pacing. Conclusion: Among these alternate right ventricular pacing locations, His bundle pacing is most like physiological pacing. Both RVOT pacing and RVA pacing worsen the normal LV systolic function with regard to strain, twist, and mechanical dyssynchrony along the LV short axis. (Echocardiography 2010;27:1219‐1227)     

Adverse Effects of Continuous Ventricular Pacing in Patients with Slower Atrial Fibrillation and Normal Left Ventricular Systolic Function

Background: Both heart rate irregularity during chronic atrial fibrillation (AF) and ventricular desynchronization imposed by ventricular pacing may compromise ventricular function. We investigated whether heart rhythm regularization achieved through ventricular overdrive pacing (VP) gives additional benefit over rate control alone in patients with AF. Methods: We studied 27 patients (mean age 72 ± 7 years) with AF and normal left ventricular (LV) systolic function who were implanted with a common VVIR pacemaker. Cardiac function was assessed by using serial echocardiographic conventional, tissue Doppler imaging (TDI) and color M‐Mode (CMM) examinations, together with B‐type natriuretic peptide (BNP) measurements. Baseline data were obtained during AF (mean heart rate 58 ± 5 beats/minute) with the pacemakers programmed to ventricular mere back‐up pacing. These data were compared to the corresponding measurements following a 2‐week VP period after the devises had been programmed to a lower rate of 70 beats/min, ensuring most of the time continuing VP. Results: Continuous VP compared to AF, reduced the LV cardiac index (2.28 ± 0.44 l/min/m² vs 2.33 ± 0.39 l/min/m², P < 0.05), increased the LV end‐systolic volume (38 ± 14 mL vs 35 ± 11 mL, P < 0.05), and decreased the TDI‐derived systolic and diastolic mitral velocity (8.1 ± 1.8 cm/s vs 8.3 ± 1.6 cm/s, and 8.1 ± 1.8 cm/s vs 8.3 ± 1.6 cm/s, respectively, both P < 0.05) and the CMM‐derived transmitral early diastolic flow propagation velocity (37.6 ± 9.2 vs 41.5 ± 9.7, P < 0.05). Following VP, both ratios E/Ea and E/Vp showed a trend toward increase (P = NS), whereas BNP rose up to 25.5% (median value, from 111 pg/mL to 165 pg/mL, P < 0.01). Conclusion: VP may be considered disadvantageous compared to slower AF.     

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.