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.     

Development of mitral and tricuspid regurgitation in right ventricular apex versus right ventricular outflow tract pacing

Purpose

This study aimed at comparing the development of tricuspid and mitral regurgitation between the right ventricular outflow tract (RVOT) and right ventricular apex (RVA) pacing.

Methods

We prospectively enrolled 164 patients for permanent pacemaker implantation due to sick sinus syndrome or atrioventricular block and randomly divided them into two equal groups to receive either RVOT or RVA pacing. Patients with heart failure or valvular disease were excluded. The post-procedural echocardiographic evaluations were performed 1 year after the pre-procedural echocardiography, and the results were compared with respect to the development of mitral and tricuspid regurgitation and probable changes in the ejection fraction (EF).

Results

Age, gender, pacing mode, and baseline cardiac rhythm did not significantly differ between the RVOT and RVA pacing groups. The incidence of mitral regurgitation was significantly higher in the RVA group (p?=?0.03), but the incidence of tricuspid regurgitation was similar in both groups. There was a trend toward less tricuspid regurgitation in the RVOT group; however, it was not statistically significant. The mean EF was not significantly different between the study groups.

Conclusion

It seems that the incidence of mitral regurgitation in RVA pacing is significantly higher than that in RVOT pacing. The formation of tricuspid regurgitation needs to be discussed in the future.

Clinical trial registration number

IRCT201103146061N1     

Functional abnormalities in patients with permanent right ventricular pacing: the effect of sites of electrical stimulation

OBJECTIVES: We sought to evaluate the long-term effects of alternative right ventricular pacing sites on myocardial function and perfusion. BACKGROUND: Previous studies have demonstrated that asynchronous ventricular activation due to right ventricular apical (RVA) pacing alters regional myocardial perfusion and functions. METHODS: We randomized 24 patients with complete atrioventricular block to undergo permanent ventricular stimulation either at the RVA (n = 12) or right ventricular outflow (RVOT) (n = 12). All patients underwent dipyridamole thallium myocardial scintigraphy and radionuclide ventriculography at 6 and 18 months after pacemaker implantation. RESULTS: After pacing, the mean QRS duration was significantly longer during RVA pacing than during RVOT pacing (151 +/- 6 vs. 134 +/- 4 ms, p = 0.03). At six months, the incidence of myocardial perfusion defects (50% vs. 25%) and regional wall motion abnormalities (42% vs. 25%) and the left ventricular ejection fraction (LVEF) (55 +/- 3% vs. 55 +/- 1%) were similar during RVA pacing and RVOT pacing (p > 0.05). However, at 18 months, the incidence of myocardial perfusion defects (83% vs. 33%) and regional wall motion abnormalities (75% vs. 33%) were higher and LVEF (47 +/- 3 vs. 56 +/- 1%) was lower during RVA pacing than during RVOT pacing (all p < 0.05). Patients with RVA pacing had a significant increase in the incidence of myocardial perfusion defects (p < 0.05) and a decrease in LVEF (p < 0.01) between 6 and 18 months, but patients with RVOT pacing did not (p > 0.05). CONCLUSIONS: This study demonstrates that preserved synchronous ventricular activation with RVOT pacing prevents the long-term deleterious effects of RVA pacing on myocardial perfusion and function in patients implanted with a permanent pacemaker.     

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。     

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)%,...     

右心室流出道间隔部起搏对左心室功能的影响

目的比较右心室流出道间隔部(RVOT)起搏与右心室心尖部(RVA)起搏的血流动力学差异;评估RVOT起搏技术的可行性与安全性。方法选择有永久起搏器置入适应证的患者75例。根据术者建议和患者意愿分为RVOT组(40例)和RVA组(35例)。所有房室传导阻滞及病窦综合征合并一度房室传导阻滞患者采用双腔起搏双腔感知触发抑制型起搏模式,心房颤动伴长间歇患者采用抑制型心室按需起搏模式。比较2组的血流动力学差异。结果 RVOT组的QRS波宽度较RVA组缩窄(23.2±28.7)ms,差异有统计学意义(P<0.01)。与RVA组比较,RVOT组LVEF、左心室短轴缩短率明显升高,左心室舒张末容积明显下降(P<0.05,P<0.01)。与术前比较,RVA组LVEF、左心室短轴缩短率明显下降,左心室舒张末容积明显升高,差异有统计学意义(P<0.01)。结论利用螺旋电极进行RVOT起搏可行且较为安全。RVOT起搏的血流动力学参数优于RVA。     

Identification of the right ventricular pacing site for cardiac resynchronization therapy (CRT) guided by electroanatomical mapping (CARTO).

BACKGROUND: The optimal left ventricle (LV) pacing site for cardiac resynchronization therapy (CRT) has been investigated, but less is known about the optimal site in the right ventricle (RV). The present study examined whether electrical resynchronization guided by electroanatomical mapping (CARTO) results in mechanical resynchronization. METHODS AND RESULTS: The study group included 13 patients indicated for CRT: 10 with nonischemic cardiomyopathy, 2 with ischemic cardiomyopathy and 1 with cardiac sarcoidosis, (mean LV ejection fraction: 32+/-10%). CARTO of the RV septum was performed to identify the site with the most delayed conduction time during LV pacing. Hemodynamic measurements were performed during conventional biventricular pacing with the RV apex and LV (C-BVP) and during biventricular pacing with the most delayed site of the RV (d-RV) and LV (D-BVP). Lead placement at 15 coronary sinus veins was examined in the 13 patients. During pacing from anterolateral veins (n=2), the d-RV was the RV apex (RVA) in 1 patient and the mid-septum in the other. During pacing from lateral veins (n=9), the d-RV comprised the RVA (n=3), the mid-septum (n=5), and the right ventricular outflow tract (RVOT) (n=1). During pacing from the posterolateral veins (n=3), the d-RV was the RVOT in all cases. In 11 of 15 sites, d-RV differed from conventional RVA. Compared with C-BVP, D-BVP produced a significant improvement in LV dp/dt. Furthermore, RV mid-septum and LV pacing markedly increased LV dp/dt and pulse pressure (PP), but RVOT and LV pacing did not. D-BVP vs C-BVP: %LV dp/dt 30+/-20 and 15+/-15%, p<0.05; RV mid-septum and LV pacing vs C-BVP: %LV dp/dt 35+/-20 and 10+/-15%, p<0.02, and vs PP 33+/-20 and 10+/-29 mmHg, p<0.02. CONCLUSIONS: For pacing from the LV lateral vein, potential improvement of cardiac performance compared with that by conventional RVA placement may be realized with concomitant pacing from the d-RV (mid-septum).     

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。     

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)     

Evolution of left ventricular function in paediatric patients with permanent right ventricular pacing for isolated congenital heart block: a medium term follow-up.

AIMS: We aimed to assess the evolution of left ventricular (LV) systolic function in children with right ventricular apical (RVA) pacing for isolated congenital heart block (ICHB) and to identify possible predictors of LV function deterioration. Right ventricular apical pacing can be detrimental to LV function in a significant number of adults. Effects in children are still controversial. METHODS AND RESULTS: Left ventricular shortening fraction (LV SF) and QRS duration were retrospectively assessed in 45 children with RVA pacing for ICHB: before pacemaker (PM) implantation, immediately after and then regularly during a follow-up of 58.69 +/- 45.23 months. Patients were categorized as stable or deteriorators according to an arbitrarily chosen cut-off point of > or =7% decrease in LV SF. Lupus status was unknown. Overall LV SF did not change significantly (41.42% +/- 8.21 before pacing, 39.77% +/- 7.03 immediately after PM implant, 37.43% +/- 9.91 with chronic pacing, P = NS). Deteriorators (n = 13) had significantly higher baseline heart rate (57.5 +/- 8.7 vs. 46.9 +/- 10.5 bpm, P < 0.05) and baseline LV SF (46.17 +/- 8.13 vs. 38.4 +/- 6.4%; P < 0.05), a significantly higher proportion of them being implanted before 2 years of age: 8 of 13 (61.5%) vs. 5 of 25 (20%) in the stable group (P < 0.05). Deteriorators had a higher incidence of an initial epicardial lead and narrower native QRS. CONCLUSION: Permanent RVA pacing for ICHB does not necessarily affect LV function in children. The risk of deterioration of LV function seems to be higher in children with higher baseline heart rate and better baseline LV SF, especially with pacing at a younger age, a narrower native QRS and RVA epicardial pacing site.     

Evaluation of left ventricular function and mitral regurgitation during left ventricular-based pacing in patients with heart failure

BACKGROUND: Beneficial effects of left ventricular (LV)-based pacing on acute hemodynamic parameters were reported in several series, but only a few studies examined the long-term effects of this new pacing procedure. AIMS: To assess long-term effects of permanent LV-based pacing on LV function and mitral regurgitation (MR) in patients with refractory congestive heart failure (CHF). METHODS: A prospective evaluation of LV function and MR was performed in 23 patients with severe but stable CHF and left bundle branch block (mean QRS: 186+/-31 ms) by radionuclide and echocardiographic techniques at baseline and 6 months after implantation of a permanent LV-based (LV alone: 13 patients; biventricular: 10 patients) pacemaker programmed either in a DDD mode (sinus rhythm; n=14) or in a VVIR mode (atrial fibrillation; n=9). RESULTS: Compared to baseline, the 6 months follow-up visit demonstrated a significant increase in radionuclide derived LV ejection fraction from 23.3+/-7 to 26.2+/-7% (P<0.01) and in echocardiographic LV fractional shortening from 13+/-4 to 16+/-6% (P<0.05), without any change in cardiac index, a significant decrease in LV end-diastolic diameter (from 73.2+/-6 to 71.2+/-7 mm; P<0.05), end-systolic diameter (from 63.6+/-6 to 60.2+/-8 mm; P<0.05) and color Doppler MR jet area (from 11.5+/-6 to 6.6+/-4 cm(1); P<0.001). A comparison of patients with LV pacing alone and patients with biventricular pacing showed similar beneficial effects of pacing on MR severity in the two subgroups and a non-significant trend for a better improvement of LV function during biventricular pacing. CONCLUSION: Thus, in patients with severe CHF and left bundle branch block, permanent LV-based pacing may significantly improve LV systolic function and decrease MR.     

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。     

右心室起搏导线位置对心脏再同步治疗效果的影响

目的 评价右心室起搏导线位置对心脏再同步治疗（CRT）效果的影响.方法 71例顽固性心力衰竭患者接受CRT手术,53例左心室导线植入侧壁或侧后壁,18例植入前壁或下壁（非侧后壁）;48例右心室导线植入心尖部,23例植入流出道间隔部.术前记录受试者心功能（NYHA分级）、QRS时限（QRSd）、左心室射血分数（LVEF）、左心室舒张末期内径（LVEDD）及左心室收缩末期内径（LVESD）;术后6个月对上述参数进行随访,比较不同右心室起搏部位对CRT临床疗效的影响.结果 术后6个月,右心室心尖部起搏组LVEF高于流出道间隔部起搏组[（0.44±0.07）对（0.40±0.07）,P=0.048],余心功能、QRSd、LVEDD、LVESD等各项指标均差异无统计学意义（P＞0.05）.根据左心室起搏部位进一步分为侧壁或侧后壁与非侧后壁两组,就侧壁或侧后壁组,右心室心尖部起搏较间隔部起搏可更好地提高心输出量LVEF[（0.45±0.07）对（0.40±0.08）,P=0.027],改善心功能[（2.59±0.59）对（3.00±0.68）,P=0.038],对于非侧后壁组,比较右心室心尖部与流出道间隔部起搏,各项指标均差异无统计学意义（P＞0.05）.结论 若无视左心室起搏部位,右心室心尖部起搏略优于流出道间隔部起搏;而对于左心室侧壁和/或侧后壁起搏者,应尽量将右心室导线置于心尖部,以获得较好疗效.     

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。     

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)     

重度三尖瓣反流患者右心室起搏部位的选择

目的 比较重度三尖瓣反流患者起搏导线放置在心尖部或流出道间隔部的难易程度.方法 2013年1月至2013年10月复旦大学附属中山医院40例符合起搏器植入适应证合并重度三尖瓣反流的患者,按随机表将其随机分成A组（拟行流出道间隔部起搏）与B组（拟行右心室心尖部起搏）.术前测定所有患者右心室体部与流出道短轴缩短分数.术中记录2组植入心室导线的曝光时间和术中脱位情况.比较术中及术后3个月流出道间隔部起搏与心尖部起搏的阈值,感知、阻抗等电极参数.结果 A、B两组各20例,A组术中曝光时间显著短于B组[（113.5±33.8）s对（156.3±58.1）s,P=0.007],A组仅1例（5.0％）发生术中脱位,B组6例（30.0％）发生术中脱位,并行导线重置,差异有统计学意义（P=0.037）.两组间术中及术后3个月起搏导线参数差异无统计学意义.所有受试者右心室体部短轴缩短分数（FS）显著大于流出道（33.7％±5.4％对27.1％±4.4％,P＜0.01）.结论 重度三尖瓣反流患者将心室导线固定于右心室流出道间隔部比心尖部更为简单易行.     

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。     

Ventricular remodeling during long-term right ventricular pacing following His bundle ablation

To investigate ventricular remodeling during long-term right ventricular (RV) pacing after His bundle ablation (HBA) in patients with atrial arrhythmias, a retrospective analysis was performed on echocardiographic data from 45 patients (mean age 57 +/- 11 years) with atrial arrhythmias who underwent HBA and pacemaker implantation (HBA-PI) to control ventricular rate. Echocardiography was performed 1 year before HBA-PI, and up to 7 +/- 2 years of follow-up was conducted. An inverse linear relation was found between the relative increase of left ventricular (LV) end-diastolic diameter (EDD) during long-term RV pacing and LVEDD before HBA-PI (r = -0.61, p<0.001). Patients were divided into 2 groups: those with LVEDDs smaller than the mean LVEDD of 50 mm (group I, 46 +/- 2 mm, n = 28) and those with LVEDDs >50 mm (group II, 56 +/- 4 mm, n = 17). Before HBA-PI, patients in group I had significantly smaller LV weights (167 +/- 44 vs 238 +/- 56 g) and LV end-systolic diameters (30 +/- 2 vs 42 +/- 7 mm) and higher LV ejection fractions (64 +/- 5% vs 49+/- 12%) than those in group II. In group I, long-term RV pacing increased LVEDD, LV end-systolic diameter, LV weight, and left atrial diameter; increased mitral regurgitation; and decreased the LV ejection fraction and LV fractional shortening. No significant changes were observed during long-term RV pacing in group II. In conclusion, long-term RV pacing after HBA adversely affects LV structure and function in patients with initially normal LV dimensions and function.     

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。