右心室非心尖部起搏与心尖部起搏对左心室功能中远期影响的meta分析

目的：系统评价右室非心尖部（RVNA）起搏与心尖部（RVA）起搏对左心室功能的中远期影响。 方法: 系统检索PubMed，EMBASE数据库和Cochrane图书馆，检索时间截止至2018-01。纳入关于RVNA起搏与RVA起搏对左心室功能中远期的随机对照试验（RCT）。采用RevMan5.3软件进行Meta分析。 结果：纳入26项研究，共包括1926例患者。在左室射血分数（LVEF）（WMD =2.94，95％CI：1.57-4.31，P <0.01）和6分钟步行试验（6MWT）（WMD =23.45，95％CI：0.68-46.22，P =0.04）方面，RVNA组优于RVA组。基础状态LVEF≤40-45％（WMD =5.03，95％CI：4.38-5.69，P <0.01）或随访时间≥12个月（WMD =3.38，95％CI：1.73-5.03，P <0.01）的患者，RVNA组对术后左心室收缩功能的影响小于RVA组。而基础状态LVEF保留（WMD =0.92，95％CI：?0.73-2.56，P =0.27）或随访时间<12个月（WMD =1.81，95％CI：?0.03-3.64，P =0.05）的患者，两组无显著差异。在血N末端脑肽前体（NT-proBNP）或脑利钠肽（BNP）方面（SMD =?0.29，95％CI：?0.70-0.13，P =0.17），RVNA组与RVA组无显著差异。 结论：对于基础状态LVEF减低（≤40-45％）或随访时间超过一年的永久起搏器置入患者，RVNA起搏比RVA起搏对术后LVEF影响小。     

格列美脲与格列本脲治疗2型糖尿病疗效的系统评价

目的系统评价格列美脲与格列本脲治疗T2DM的疗效。方法计算机检索PubMed、万方等数据库从建库至2010年12月间的有关文献。按Cochrane系统评价的方法评价纳入研究的质量,使用Review Manager4．2软件进行荟萃分析。结果共纳入9个随机对照试验。结果显示：格列美脲在降低HbA1c[P=0．08,加权均数差（WMD）=-0．18,95％CI（-0．39,0．02）]、FPG[P=0．06,WM=-0．46,95％CI（-0．94,0．01）]、餐后血糖[P=O．73,WMD=-0．16,95％CI（-1．08,0．76）]、TC[P=0．22,WMD=-0．2,95％CI（-0．51,0．12）]和TG[P=0．06,WMD=-0．30,95％CI（-0．61,0．01）]方面与格列本脲无差异;在相同血糖水平下,格列美脲组FIns[P〈0．05,WMD=-0．83,95％CI（-1．21,0．45）]及餐后胰岛素[P〈0．05,WMD=-5．94,95％CI（-8．79,-3．10）]升高程度低于格列本脲组;低血糖发生率格列美脲组低于格列本脲组[P〈0．05,RR=0．66,95％CI（0．53,0．81）];在降低BMI方面格列美脲优于格列本脲[P=0．02,WMD=-1．49,95％CI（-2．7,-0．27）]。结论与格列本脲相比,格列美脲在降低血糖的同时,还能改善胰岛素抵抗及减轻体重,且低血糖发生率低,是安全有效的治疗T2DM的药物。     

规律运动对中国2型糖尿病患者血糖血脂治疗效果的荟萃分析

目的系统评价规律运动对中国2型糖尿病（T2DM）患者的血糖、血脂的影响。方法计算机检索中国生物医学文献数据库（1978-2011．2）、中文科技期刊全文数据库（重庆维普）（1989-2011．2）、万方数据库（1982-2011．2）、中国期刊全文数据库（1994-2011．2）、中国学术会议论文全文数据库（1998-2011．2）并手工检索入选参考文库中未检索出的文献,纳入T2DM患者实施规律运动治疗（运动持续时间I〉3个月）＋常规治疗与仅有常规治疗或随意运动治疗＋常规治疗的随机对照试验（RCTs）。由两位评价者按纳入、排除标准,依据Cochrane系统评价员手册4．2．6的文献质量评价方法独立进行质量评价和资料提取,并交叉核对,然后采用RevMan5．1软件进行荟萃分析。结果共有20篇文献,23项RCTs符合要求,纳入文献总体质量不高,16篇B级,4篇C级。荟萃分析结果显示：与对照组相比,规律体育运动可显著改善血糖控制,降低糖化血红蛋白（HbAlc）[加权均数差（WMD）=-1．18,95％CI：-1．6-0．69,P〈0．01]、甘油三酯（TG）（WMD=-0．27,95％CI：一0．36--0．19,P〈0．01）、总胆固醇（TC）（WMD=-0．78,95％CI：-0．88-0．68,P〈0．01）,提高高密度脂蛋白胆固醇（HDL-C）（WMD=0．17,95％CI：0．12-0．23,P〈0．01）并降低低密度脂蛋白胆固醇（LDL—c）（WMD=-0．48,95％CI：-0．64--0．32）,P〈0．01）。结论尽管现有研究表明,规律运动可明显改善中国T2DM患者血糖控制,降低HbAlC、TG、TC和LDL-C,提高HDL-C,但仍需更多较高质量的RCTs支持相应结论。     

希氏束起搏在心力衰竭患者中应用疗效的meta分析

目的通过meta分析方法综合评估希氏束起搏在心力衰竭患者中应用的疗效。方法检索数据库(Cochrane Library、PubMed、Embase、万方数据库、维普数据库、中国知网数据库、中国生物医学数据库)中评估希氏束起搏在心力衰竭患者中应用疗效相关文献,收集符合纳入标准的研究中患者基线资料及随访前后QRS波时限、左室射血分数、起搏阈值等指标并进行meta分析。采用Stata 12.0软件分析。结果共纳入14篇研究,包括539例心力衰竭患者,平均年龄70.9岁。meta分析结果显示,希氏束起搏显著缩短QRS波时限(WMD=-51.51 ms, 95%CI=-59.50～-43.52,P0.01),改善心力衰竭患者左室射血分数(WMD=10.91%, 95%CI=7.55～14.27,P0.01)。然而与基线相比,希氏束起搏阈值存在上升趋势(WMD=0.26 V,95%CI=0.15～0.36,P0.01)。结论希氏束起搏可显著改善心力衰竭患者心功能。未来需要更多大样本临床随机对照研究来证实希氏束起搏在心力衰竭患者中的应用疗效。     

不同起搏方式对高右室起搏比例患者心功能及心房颤动的影响

目的：探讨不同起搏部位对高右室起搏比例、缓慢性心律失常患者新发心房颤动（AF）及心功能的影响。方法：入选我院心内科2005年1月至2011年1月期间置入 DDD 永久起搏器的缓慢性窦房结功能失调或Ⅱ度以上房室传导阻滞患者,选择其中高右室起搏比例者（右室起搏累积百分比＞50％）共120例,随机分为右室心尖部（RVA）起搏组（n＝47）及右室间隔部（RVS）起搏组（n ＝73）。随访内容包括起搏器置入术前、术后3年 AF 发生情况和超声心动图参数。结果：随访期间 RVA 组新发 AF 患者比例高于 RVS 组（23．40％对16．43％,P ＝0．03）。术后3年,与 RVA 组相比,RVS 组左房内径（LAD）、左室舒张末期内径（LVEDD）明显缩小,左室射血分数（LVEF）则明显升高（P ＜0．05）。结论：对于 DDD 起搏模式下高右室起搏比例患者,与 RVA 起搏相比,RVS 起搏可显著改善患者心功能,减少 AF 的发生。     

右室间隔部起搏对心功能影响的Meta分析

目的系统评价右室间隔部（RVS）起搏对心功能的影响。方法计算机检索Cochrane图书馆（2010年第1期）、PubMed、EMbase,同时检索CBM、CNKI、VIP和万方数据库,检索时间截至2010年3月,收集右室间隔部（RVS）起搏对比右室心尖部（RVA）起搏对心功能影响的随机对照试验（RCT）,并按Cochrane协作网推荐的方法进行质量评价、资料提取和Meta分析。结果共纳入35个RCT,包括2034例患者。Meta分析结果显示：①左室射血分数：RVS起搏在3个月和18个月的左室射血分数均高于RVA起搏,差异有统计学意义[WMD=3.53,95%CI：1.02～6.04];[WMD=7.44,95%CI：5.46～9.42]。②QRS波时限：RVS起搏在术后即时和3个月的QRS波时限均小于RVA起搏,差异有统计学意义[WMD=-27.7,95%CI：-34.24～-21.15];[WMD=-17.02,95%CI：-24.14～-9.90]。③起搏参数：术后3个月时RVS起搏的起搏阈值与RVA起搏无差别。RVS起搏的感知阈值和阻抗均低于RVA起搏。结论右室间隔部起搏能给患者带来良好的近生理状态的双心室电传导,并改善患者的血流动力学,右室间隔部有望成为首选的心室起搏部位。     

白藜芦醇对快速起搏右心房诱发的持续性心房颤动猪心房结构重构的影响

目的 观察快速起搏猪右心房制备持续性心房颤动（AF）的效果,探讨白藜芦醇（RES）干预对持续性AF猪的心房结构重构的影响.方法 18只小家猪（雌雄不拘）按完全随机设计的分组方法（采用动物编号和随机分组表）分为起搏组（ATP组）、假手术组（Sham组）和RES干预组各6只,采用Seldinger血管穿刺技术送入双极电极至右心房并连接实验用起搏器（AOO）,ATP组和RES干预组的右心房快速起搏（500次/min）2周,制备持续性AF实验模型.3组猪分别于起搏前和起搏2周后进行电生理和经胸壁超声心动图检查,以检测AF的持续时间、左右心房大小及左心房收缩末面积.RES干预组猪于起搏前1周开始服用RES（2.5 mg·kg-1·d-1）.起搏2周后取各组猪的左右心房组织标本,观察心房组织形态学和间质纤维化的改变,用免疫组织化学分析软件计算胶原容积分数（CVF）来反映间质纤维化程度.结果 （1）起搏2周后,ATP组AF的发生率较RES干预组明显升高（100％比66.7％,x2=10,P＜0.01）、持续时间延长[（26.41±9.89）min比（9.56±1.36） min,F=10.7,P=0.01].（2）起搏2周后,ATP组和RES干预组猪的左右心房明显比起搏前增大;但RES干预组的左心房收缩末面积明显低于ATP组[（599.2±8.7） mm2比（744.3±29.9） mm2,F=130.61,P＜0.01].（3）RES干预组左右心房组织CVF明显低于ATP组（56％±6％比73％±7％;59％±6％比75％±7％,均为P＜0.01）.结论 快速起搏猪右心房可成功制备持续性AF模型;RES干预可以明显抑制快速起搏右心房诱发的持续性AF猪的心房结构重构,减少AF的发生.     

ⅤⅥ起搏器更换者心功能和心房颤动发生情况的临床观察

目的评估长期VVI起搏对患者心功能和心房颤动（房颤）发生的影响。方法对植入VVI起搏器的103例患者分别于VVI起搏器首次植入时和因脉冲发生器电池耗竭行更换术前进行临床、心电图、24h动态心电图、超声心动图检查，并评价心功能（NYHA分级）和房颤发生情况。结果VVI起搏器平均更换时间为8．4年。首次VVI起搏器植入时左心房内径平均36．27mm，左心室舒张末内径49．62mm，患者在更换VVI起搏器时左心房内径、左心室舒张末内径分别增加到40．39mm（P〈0．001）和53．27mm（P=0．007）。左心室射血分数由首次植入时的0．65下降到更换时的0．61（P=0．0485）。同时发现患者心力衰竭加重（P=0．0284），持续性房颤发生率增加（P=0．0283）。结论长期VVI起搏引起患者心功能恶化，持续性房颤发生率增加。     

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。     

持续气道正压通气对中国阻塞性睡眠呼吸暂停低通气综合征患者胰岛素抵抗影响的荟萃分析

目的荟萃分析方法评价持续气道正压通气（CPAP）对中国阻塞性睡眠呼吸暂停低通气综合征（OSAHS）患者胰岛素抵抗的影响。方法计算机检索PubMed、中国学术期刊全文数据库、中国生物医学文献数据库、万方资源数据库、重庆维普网和中国重要会议论文全文数据库并手工检索相关期刊,全面收集持续气道正压通气对我国阻塞性睡眠呼吸暂停低通气综合征胰岛素抵抗的临床研究,按照纳入、排除标准选择试验并评价质量,采用Stata11．0软件进行荟萃分析。结果最终纳入13篇文献。荟萃分析结果显示：CPAP治疗后单纯OSAHS患者及OSAHS合并糖尿病患者空腹血糖（FBG）明显降低,差异有统计学意义[WMD：0．473,95％CI（0．157,0．790）,P=0．003;WMD=1．358,95％CI（0．921,1．794）,P=0]。CPAP对两组患者空腹胰岛素（FINS）未见明显影响[WMD=0．624,95％CI（-0．512,1．759）,P=0．282;WMD=0．275,95％CI（-0．416,0．965）,P=0．435]。CPAP能降低两组患者胰岛素抵抗指数（HOMA-IR）,差异有统计学意义[WMD=0．483,95％CI（0．119,0．846）,P=0．009;WMD=0．726,95％CI（0．023,1．430）,P〈0．05]。CPAP对OSAHS合并糖尿病患者糖化血红蛋白（HbAlc）有影响,差异有统计学意义[WMD=1．03,95％CI（0．71,1．34）,P〈0．05]。CPAP治疗前后FBG、FINS、HOMA-IR、HbAlc漏斗图均基本呈现下宽上窄左右对称的图形,经Egger检验后,提示单纯OSAHS组HOMA—IR存在明显发表偏倚,其余指标均不存在明显发表偏倚。结论无论是否合并糖尿病,CPAP均改善我国OSAHS患者胰岛素抵抗。     

Comparison of Permanent Left Ventricular and Biventricular Pacing in Patients with Heart Failure and Chronic Atrial Fibrillation: A Prospective Hemodynamic Study

BACKGROUND: Left ventricular pacing (LVP) and biventricular pacing (BVP) have been proposed as treatments for patients with advanced heart failure complicated by discoordinate contraction due to intraventricular conduction delay. For patients in sinus rhythm, BVP works in part by modulating the electronic atrial-ventricular time delay and thus optimizing contractile synchrony, the contribution of atrial systole, and reducing mitral regurgitation. However, little is known of the mechanisms of BVP in heart failure patients with drug-resistant chronic atrial fibrillation. HYPOTHESIS AND METHODS: LVP differs from BVP because hemodynamic and clinical improvement occurs in association with prolongation rather than shortening of the QRS duration. We sought to determine if LVP or BVP improves mechanical synchronization in the presence of atrial fibrillation. Thirteen patients with chronic atrial fibrillation, severe heart failure and QRS >or=140 ms received (after His bundle ablation) a pacemaker providing both LVP and BVP. The mean age was 62 +/- 6 years and left ventricular ejection fraction was 24 +/- 8%. After a baseline phase of one month with right ventricular pacing, all patients underwent in random order 2 phases of 2 months (LVP and BVP). At the end of each phase, an echocardiogram, a hemodynamic analysis at rest and during a 6-minute walking test and a cardio-pulmonary exercise test were performed. RESULTS: LVP and BVP provided similar performances at rest (p = ns). The 6-minute walking test revealed similar performances in both pacing modes but patients were significantly more symptomatic at the end of the test with LVP ( p = 0.035). The cardio-pulmonary exercise test showed higher performances with BVP (92 +/- 34 Watts) vs. LVP (77 +/- 23; p = 0.03). LVP was associated with significantly more premature ventricular complexes recorded during the 6 minute walking test (49 +/- 71) than BVP (10 +/- 23; p = 0.04). CONCLUSIONS: In this small series of patients with atrial fibrillation, congestive heart failure and a prolonged QRS duration, LVP and BVP provided similar hemodynamic effects at rest whereas BVP was associated with better hemodynamic effects during exercise and fewer premature ventricular complexes. Although the mechanisms for the observed differences are uncertain, it is possible that there is worsening of right ventricular function due to a rise in left-to-right electromechanical delay during exercise. Increased catecholamines release might contribute to the lower exercise tolerance and greater number of premature ventricular complexes recorded during exercise observed during LVP compared to BVP. RECOMMENDATIONS: Patients with atrial fibrillation, heart failure and QRS prolongation who are candidates for His-bundle ablation and cardiac resynchronization therapy may respond better to BVP rather than to LVP.     

Acute hemodynamic effects of biventricular and left ventricular pacing in chronic pacemaker-dependent patients with advanced heart failure

The beneficial hemodynamic effects of cardiac resynchronization in patients with intraventricular conduction delay have been demonstrated. The potential hemodynamic effects of cardiac resynchronization to compensate the pacing-induced left ventricular conduction delay in chronically paced heart failure patients are not as well established. The aim of the study was to evaluate the acute hemodynamic effects of biventricular and left ventricular pacing in chronically paced patients with advanced heart failure.Fourteen consecutive pacemaker or defibrillator patients with permanent atrial fibrillation and AV block (11 male, 3 woman, mean age: 68 +/- 7 years) were enrolled in this study. There were 5 ischemic (36%) and 9 nonischemic (64%) patients (mean left ventricular ejection fraction: 19 +/- 5%; mean end-diastolic left ventricular diameter: 71 +/- 11 mm). In all patients a right ventricular and left ventricular (via coronary sinus) pacing lead was placed. The aortic and left ventricular hemodynamic measurements were performed using a two-channel micro-tip catheter. The measurements of the aortic pulse pressure (APP) and (dP/ dtmax) were performed during right ventricular apical pacing (RVP), left ventricular (LVP), and biventricular pacing (BVP) (70 bpm).Compared to RVP, LVP and BVP increased APP and dP/dtmax (35.8 +/- 4.2 vs 43.3 +/- 4.5 and 41.2 +/- 4 mmHg; p < 0.001) and (758 +/- 56 vs 967 +/- 60 and 961 +/- 62 mmHg/s; p < 0.001). LVP and BVP showed a comparable hemodynamic response. The hemodynamic effects were not related to the width of the paced QRS complex. Every patient showed improved hemodynamics during LVP and BVP unrelated to the underlying heart disease and to the baseline level of left ventricular dysfunction. BVP and LVP pacing acutely improve contractile left ventricular function in chronically paced patients with advanced heart failure.     

Improvement of left ventricular wall synchronization with multisite ventricular pacing in heart failure: a prospective study using Doppler tissue imaging

We sought to assess right, left and biventricular pacing effects on myocardial function by using pulsed-Doppler tissue imaging (DTI) and automated border detection (ABD) techniques which provide electromechanical delay (EMD) assessment of the different left ventricular walls. METHODS: 15 patients (67+/-7 years) with drug-resistant primitive dilated cardiomyopathy and QRS> or =140 ms received a pacemaker for multisite ventricular pacing. Echocardiography was performed after 1 month of biventricular pacing (BVP). Echocardiographic measurements were recorded during spontaneous rhythm (SpR), right ventricular pacing (RVP), left ventricular pacing (LVP) and BVP. RESULTS: LV ejection fraction was statistically similar between the four rhythms. BVP showed a significant EMD decrease for the lateral LV wall vs. SpR, RVP and even LVP. LVP resulted in significantly longer aortic pre-ejection time vs. BVP while the EMD temporal dispersion (time between the shortest regional EMD and the longest one) was similar in the two modes. CONCLUSIONS: BVP and LVP substantially reduce the EMD temporal dispersion of the four LV walls, but with a longer aortic pre-ejection time for LVP. In RVP, LVP and BVP, the septal LV wall is always activated later than during SpR. BVP and LVP are associated with a mitral regurgitation reduction.     

Biventricular pacing and left ventricular pacing in heart failure: similar hemodynamic improvement despite marked electromechanical differences

INTRODUCTION: We conducted an acute echocardiographic study comparing hemodynamic and ventricular dyssynchrony parameters during left ventricular pacing (LVP) and biventricular pacing (BVP). We sought to clarify the mechanisms responsible for similar hemodynamic improvement despite differences in electrical activation. METHODS AND RESULTS: Thirty-three patients underwent echocardiography prior to implantation with a multisite pacing device (spontaneous rhythm [SR]) and 2 days after implantation (BVP and LVP). Interventricular dyssynchrony (pulsed-wave Doppler), extent of myocardium displaying delayed longitudinal contraction (%DLC; tissue tracking), and index of LV dyssynchrony (pulsed-wave tissue Doppler imaging) were assessed. Compared to SR, BVP and LVP caused similar significant improvement of cardiac output (LVP: 3.2 +/- 0.5, BVP: 3.1 +/- 0.7, SR: 2.3 +/- 0.6 L/min; P < 0.01) and mitral regurgitation (LVP: 25.1 +/- 10, BVP: 24.7 +/- 11, baseline: 37.9 +/- 14% jet area/left atria area; P < 0.01). LVP resulted in a smaller index of LV dyssynchrony than BVP (29 +/- 10 vs 34 +/- 14; P < 0.05). However, LVP exhibited a longer aortic preejection delay (220 +/- 34 vs 186 +/- 28 msec; P < 0.01), longer LV electromechanical delays (244.5 +/- 39 vs 209.5 +/- 47 msec; P < 0.05), greater interventricular dyssynchrony (56.6 +/- 18 vs 31.4 +/- 18; P < 0.01), and higher%DLC (40.1 +/- 08 vs 30.3 +/- 09; P < 0.05), leading to shorter LV filling time (387 +/- 54 vs 348 +/- 44 msec; P < 0.05) compared to BVP. CONCLUSION: Although LVP and BVP provide similar hemodynamic improvement, LVP results in more homogeneous but substantially delayed LV contraction, leading to shortened filling time and less reduction in postsystolic contraction. These data may influence the choice of individual optimal pacing configuration.     

Meta-analysis of randomized controlled trials comparing isolated left ventricular and biventricular pacing in patients with chronic heart failure

Cardiac resynchronization therapy (CRT) has been mostly achieved by biventricular pacing (BVP) in patients with chronic heart failure (CHF), although it can also be provided by left ventricular pacing (LVP). The superiority of BVP over LVP remains uncertain. The present meta-analysis of randomized controlled trials was performed to compare the effects of LVP to BVP in patients with CHF. Outcomes analyzed included clinical status (6-minute walk distance, peak oxygen consumption, quality of life, New York Heart Association class), LV function (LV ejection fraction), and LV remodeling (LV end-systolic volume). Five trials fulfilled criteria for inclusion in analysis, which included 574 patients with CHF indicated for CRT. After a midterm follow-up, pooled analysis demonstrated that LVP resulted in similar improvements in 6-minute walk distance (weighted mean difference [WMD] 11.25, 95% confidence interval [CI] -12.39 to 34.90, p = 0.35), quality of life (WMD 0.34, 95% CI -3.72 to 4.39, p = 0.87), peak oxygen consumption (WMD 1.00, 95% CI -0.84 to 2.85, p = 0.29), and New York Heart Association class (WMD -0.19, 95% CI -0.79 to 0.42, p = 0.54). There was a trend toward a superiority of BVP over LVP for LV ejection fraction (WMD 1.28, 95% CI -0.11 to 2.68, p = 0.07) and LV end-systolic volume (WMD -5.73, 95% CI -11.86 to 0.39, p = 0.07). In conclusion, LVP achieves similar improvement in clinical status as BVP in patients with CHF, whereas there was a trend toward superiority of BVP over LVP for LV reverse modeling and systolic function.     

Echocardiographic assessment during exercise of heart failure patients with cardiac resynchronization therapy

This prospective echocardiographic study investigated the respective impacts of left ventricular (LV) pacing and simultaneous and sequential biventricular pacing (BVP) on ventricular dyssynchrony during exercise in 23 patients with compensated heart failure and ventricular conduction delays. During exercise, LV pacing and BVP significantly (p <0.05) improved mitral regurgitation and LV dyssynchrony compared with spontaneous activation. LV segmental electromechanical delays were significantly prolonged during LV pacing, leading to increased systolic time (p <0.05), decreased LV filling time (p <0.05), and decreased stroke volume (p <0.05) compared with BVP. After optimization of the interventricular delay with sequential BVP, additional benefit was obtained during exercise in terms of stroke volume and mitral regurgitation (p <0.05). The optimal interventricular delay was different at rest and during exercise in 57% of the patients. Changes from at rest to exercise in LV dyssynchrony were correlated with changes in stroke volume (r = -0.61, p <0.01) and changes in mitral regurgitation (r = 0.60, p <0.01).     

Effects of right, left, and biventricular pacing on myocardial perfusion in ischemic conditions

Objectives: In normal hearts, the distribution of regional myocardial perfusion is altered by ventricular pacing. Little is known about the impact of ventricular pacing on regional myocardial perfusion in ischemic conditions. In this acute echocardiographic study, we compared the respective effects of right ventricular pacing (RVP), left ventricular pacing (LVP), and biventricular pacing (BVP) on regional perfusion in a swine model of graded ischemia.
Methods and Results: Ventricular pacing leads were placed at the apex of the right ventricle and on the lateral wall of the left ventricle in nine open-chest pigs. Myocardial contrast echocardiography was successively performed during spontaneous rhythm (SR), RVP, LVP, and BVP in random order at baseline and during three stages of incremental ischemia (left anterior descending + circumflex). At baseline, RVP decreased myocardial perfusion of the septal and inferior walls compared to SR (P < 0.05), whereas LVP decreased perfusion of the lateral wall (P < 0.05). No significant differences were observed in regional perfusion during BVP compared to SR. In ischemic conditions, RVP worsened myocardial perfusion in the ischemic anterior wall as well as in the septal and inferior walls (P < 0.05), whereas both LVP and BVP did not alter perfusion in the ischemic area compared to SR.
Conclusion: Compared to baseline, in ischemic conditions, RVP has a more pronounced detrimental impact on perfusion abnormalities. In contrast, BVP induced a significant improvement in local myocardial perfusion. Therefore, BVP could be preferred to RVP in patients with ischemic cardiomyopathy.     

Comparison of chronic biventricular pacing between epicardial and endocardial left ventricular stimulation using Doppler tissue imaging in patients with heart failure.

In patients with a wide QRS, drug-resistant heart failure, and a coronary sinus that is unsuitable for transvenous biventricular pacing (BVP), a transseptal approach from the right to left atrium can allow endocardial left ventricular (LV) pacing (with permanent anticoagulant therapy) instead of epicardial pacing via the coronary sinus branches. We sought to compare the effects of endocardial pacing with those of epicardial LV pacing on regional LV electromechanical delay (EMD) and contractility. Twenty-three patients (68 +/- 8 years) with severe heart failure and QRS > or =130 ms received a pacemaker for BVP. Fifteen patients underwent epicardial LV pacing, and 8 underwent endocardial LV pacing because of an unsuitable coronary sinus. All LV leads were placed at the anterolateral LV wall. Six months after implant, echocardiography and Doppler tissue imaging were performed. LV wall velocities and regional EMDs (time interval between the onset of the QRS and local ventricular systolic motion) were calculated for the 4 LV walls and compared for each patient between right ventricular (RV) and BVP. The amplitude of regional LV contractility was also assessed. Epicardial BVP reduced the septal wall EMD by 11% versus RV pacing (p = 0.05) and the lateral wall EMD by 41% versus RV pacing (p <0.01). With endocardial BVP, the septal and lateral EMDs were 21.3% and 54%, respectively (p <0.01, compared with epicardial BVP). The mitral time-velocity integral increased by 40% with endocardial BVP versus 2% with epicardial BVP (p <0.01). The amplitude of the lateral LV wall systolic motion increased by 14% with epicardial BVP versus 31% with endocardial BVP (p = 0.01). This resulted in a LV shortening fraction increase of 25% in patients with endocardial BVP (p = 0.05). However, all patients were clinically improved at the end of follow-up. Thus, in heart failure patients with BVP, endocardial BVP provides more homogenous intraventricular resynchronization than epicardial BVP and is associated with better LV filling and systolic performance.     

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。     

Biventricular Pacing in End-Stage Heart Failure Improves Functional Capacity and Left Ventricular Function

Background Asynchronous patterns of contraction and relaxation may contribute to hemodynamic and functional impairment in heart failure. In 1993, we introduced biventricular pacing as a novel method to treat heart failure by synchronous stimulation of the right and left ventricles after an appropriate atrioventricular delay. The objectives of this study were to assess the early and long-term effects of this therapy on functional capacity and left ventricular function in patients with severe heart failure and left bundle branch block.Methods and Results Twelve patients with end-stage congestive heart failure, sinus rhythm and complete left bundle branch block were treated with biventricular stimulation at optimized atrioventricular delay. The NYHA functional class and maximal bicycle exercise capacity were assessed. Systolic and diastolic left ventricular function were studied with echocardiography and radionuclide angiography. Data was collected at various intervals during 1-year follow-up. Cumulative survival [95% CI] was 66.7% [40.0,93.4] at 1 year and 50 % [21.8, 78.2] at 2 and 3 years. Median NYHA class improved from class IV to class II at 1 year (p=0.008). After 6weeks an increase in exercise capacity occurred, which was sustained. A less restrictive left ventricular filling pattern, an increase in dP/dt and left ventricular ejection fraction, and a decrease in mitral regurgitation were observed early and long-term.Conclusions Biventricular pacing at optimized atrioventricular delay results in improvement in functional capacity, which is associated with improved systolic and diastolic left ventricular function, and a decrease in mitral regurgitation during short- and long-term follow-up.