Acute hemodynamic effects of biventricular DDD pacing in patients with end-stage heart failure

Objectives. The aim of this study was to assess the potential acute benefit of multisite cardiac pacing with optimized atrioventricular synchrony and simultaneous biventricular pacing in patients with drug-refractory congestive heart failure (CHF).

Background. Prognosis and quality of life in severe CHF are poor. Various nonpharmacological therapies have been evaluated but are restricted in their effectiveness and applications. In the early 1990s, dual chamber pacing (DDD) pacing was proposed as primary treatment of refractory CHF but results were controversial. Recently, tests to evaluate the effect of simultaneous pacing of both ventricles have elicited a significant improvement of cardiac performance.

Methods. Acute hemodynamic study was conducted in 18 patients with severe CHF (New York Heart Association class III and IV) and major intraventricular conduction block (IVCB) (QRS duration = 170 ± 37 ms). Using a Swan-Ganz catheter, pulmonary artery pressure, pulmonary capillary wedge pressure (PCWP) and cardiac index (CI) were measured in different pacing configurations: atrial pacing (AAI) mode, used as reference, single-site right ventricular DDD pacing and biventricular pacing with the right ventricular lead placed either at the apex or at the outflow tract.

Results. The CI was significantly increased by biventricular pacing in comparison with AAI or right ventricular (RV). DDD pacing (2.7 ± 0.7 vs. 2 ± 0.5 and 2.4 ± 0.6 l/min/m², p < 0.001). The PCWP also decreased significantly during biventricular pacing, compared with AAI (22 ± 8 vs. 27 ± 9 mm Hg; p < 0.001).

Conclusions. This acute hemodynamic study demonstrated that biventricular DDD pacing may significantly improve cardiac performance in patients with IVCB and with severe heart failure, in comparison with intrinsic conduction and single-site RV DDD pacing.     

左室和双心室起搏对心肌病晚期心衰患者的血流动力学研究

目的　对心电图呈左束支阻滞的晚期心肌病患者行左室和双心室起搏 ,了解左室和双心室起搏的急性期血流动力学效应。方法　对 16例心电图呈左束支阻滞的晚期心肌病患者行左室游离壁和双心室起搏 ,记录左室、双心室和基础状态下的左室腔内dP/dtmax、主动脉根部压力和心电图QRS波宽度。结果　左室和双心室起搏分别使左室dP/dtmax提高 2 1%和 18% (P <0 0 1) ,而左室和双心室起搏组无显著差异 (P >0 0 5 ) ;左室起搏和双心室起搏使主动脉收缩压较基础状态升高 6 %和 5 % (P <0 0 1) ,左室和双心室起搏组间差异不显著 (P >0 0 5 ) ;左室起搏心电图QRS间期缩短不明显 (P >0 0 5 ) ,而双心室起搏QRS间期明显缩短(P <0 0 5 )。结论　对于心电图呈LBBB型的心肌病终末期心衰患者 ,行双心室起搏和左室游离壁起搏均使患者的急性期血流动力学得到显著改善 ,两者的效果相当     

右心房左心室起搏对充血性心力衰竭患者急性血流动力学影响的研究

充血性心力衰竭 (CHF)为器质性心脏病终末阶段 ,病死率高。近年来 ,国内外学者进行了双心室同步起搏治疗CHF的实验研究和初步的临床应用 ,并取得了良好效果。但双心室起搏治疗CHF的费用昂贵 ,严重阻碍了这项技术的发展。自 2 0 0 1年 1 2月以来 ,对 6例需植入DDD起搏器且有不同程度CHF的患者行右心房左心室起搏时的急性血流动力学进行了研究。资料和方法　 6例患者均为经严格选择需植入DDD起搏器且有不同程度CHF患者 ,男性 4例、女性 2例。年龄49～ 72 (60 2± 9 6)岁 ,其中病态窦房结综合征 (SSS) 4例 ,2例合并有完全性左束支阻…     

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.     

Long-term left ventricular pacing: assessment and comparison with biventricular pacing in patients with severe congestive heart failure

OBJECTIVE

The purpose of this study is to report prospectively the results of six-month follow-up of permanent left ventricular (LV) based pacing in patients with severe congestive heart failure (CHF) and left bundle branch block (LBBB).

BACKGROUND

Left ventricular pacing alone has been demonstrated to result in identical improvement compared to biventricular pacing (BiV) during acute hemodynamic evaluation in patients with advanced CHF and LBBB. However, to our knowledge, the clinical outcome during permanent LV pacing alone versus BiV pacing mode has not been evaluated.

METHODS

Pacing configuration (LV or BiV) was selected according to the physician’s preference. Patient evaluation was performed at baseline and at six months.

RESULTS

Thirty-three patients with advanced CHF and LBBB were included. Baseline characteristics of LV (18 patients) and BiV (15 patients) pacing groups were similar. During the six-month follow-up period, seven patients died three BiV and four LV). In the surviving patients at 6 months, 8 of 14 patients in the LV group and 9 of 12 in the BiV group were in New York Heart Association class I or II (p = 0.39). No significant difference was observed between the two groups in terms of objective parameters except for LV end-diastolic diameter decrease (−4.4 mm in BiV group vs. −0.7 mm in LV group; P = 0.04).

CONCLUSION

At six-month follow-up, a trend toward improvement was observed in objective parameters in patients with severe CHF and LBBB following LV-based pacing. The two pacing modes (LV and BiV) were associated with almost equivalent improvement of subjective and objective parameters.     

Acute and chronic haemodynamic effects of biventricular pacing and of switching to different pacing modalities in heart failure patients

BACKGROUND: In patients with severe heart failure, sinus rhythm and wide QRS complex biventricular (BiV) pacing leads to clinical and haemodynamic improvement, but the immediate reversibility of these changes is not known. METHODS: We assessed the acute and medium-term (3-month) haemodynamic effects of BiV pacing and of switching to other pacing modalities in 21 patients with severe heart failure, sinus rhythm and QRS>or=130 ms. Haemodynamic studies were performed: 1) at the time of implantation of a BiV pacing device, during AAI pacing, atrial synchronous right ventricular (RV) pacing, atrial synchronous left ventricular (LV) pacing and atrial synchronous BiV pacing (all at 100 bpm); 2) after 3 months of continuous BiV pacing--with evaluations being made by switching to RV and the other pacing modalities. RESULTS: At both the acute and medium-term evaluations, BiV pacing provided the greatest improvement in cardiac index. Switching from BiV to RV pacing led to a more marked decrease in the cardiac index at 3 months. No strict correlation was evident between acute and medium-term effects of BiV pacing on cardiac index. CONCLUSION: Cardiac resynchronization by BiV pacing provides acute/medium-term improvements in cardiac index. Sudden, medium-term failure of LV stimulation can lead to an even more pronounced haemodynamic derangement than that inducible by RV pacing at baseline. Acute haemodynamic evaluations do not seem to provide a powerful way for identifying medium-term responders.     

左心室和双心室起搏对心力衰竭患者运动能力影响的荟萃分析

目的比较左心室起搏（LVP）和双心室起搏（BVP）对心力衰竭患者运动能力的影响。方法在MEDLINE、Cochrane临床试验中心登记库、EMBASE和中国期刊网中检索以心力衰竭为研究对象,评价了6min步行距离（6MWD）和／或峰值耗氧量（PVO2）的LVP与BVP对比的研究。结果共检索到87篇文献,其中3项研究符合人选标准,共纳入73例患者。交叉起搏4～8周后,BVP组比LVP组的PVO2明显增加[加权均数差（WMD）=-0．35ml·kg·min^-1,95％可信区间（CI-0．66,-0．05）,P=0．02];6MWD在BVP组有增加的趋势,但差异无统计学意义（WMD=-1．2m,95％CI（-7．98,5．57）,P=0．73]。结论BVP对心力衰竭患者运动能力的改善可能优于LVP。     

对心肌病晚期心力衰竭患者行左心室和双心室起搏的血流动力学研究

目的　了解左心室和双心室起搏的急性期血流动力学效应。方法　对 16例心电图呈左束支传导阻滞 (LBBB)的晚期心肌病患者行左室游离壁和双心室起搏 ,记录左室、双心室和基础状态下的左室腔内最大压力上升速率 (dP dtmax)、主动脉根部压力和心电图QRS波宽度。结果　左室和双心室起搏分别使左室dP dtmax提高 2 1%和 18% (P <0 0 1) ,左室和双心室起搏组间无显著差异 ;左室起搏和双心室起搏使主动脉收缩压较基础状态升高 6 %和 5 % (P <0 0 1) ,左室和双心室起搏组间差异不显著 ;左室起搏心电图QRS间期缩短不明显 ,而双心室起搏QRS间期明显缩短。结论　对于心电图呈LBBB型的心肌病终末期心力衰竭患者 ,行双心室起搏和左室游离壁起搏均使患者的急性期血流动力学得到显著改善 ,两者的效果相当     

Transoesophageal left ventricular pacing in heart failure patients with permanent right ventricular pacing.

BACKGROUND: Previous studies of biventricular (BV) pacing for treatment of heart failure (HF) patients with left bundle branch block (LBBB) evaluated responders to BV pacing with acute transvenous left ventricular (LV) pacing and arterial pulse pressure (PP). The aim of this study was to assess transoesophageal LV pacing in evaluation of the haemodynamic response with a view to upgrading responders from permanent right ventricular (RV) pacing to BV pacing. METHODS AND RESULTS: Ten HF patients (age 62+/-8 years; one female, nine males) in NYHA III, LV ejection fraction 24+/-9% and permanent RV pacing by means of an implanted pacemaker or ICD were tested using transoesophageal LV pacing and PP. Permanently RV-paced HF patients were analysed with transoesophageal atrial sensed LV pacing in VAT mode with a different AV delay (n = 6) and with transoesophageal LV pacing in V00 mode during atrial fibrillation (n = 4). In five responders, PP was higher during transoesophageal LV pacing than PP during RV pacing (74+/-42 versus 57+/-31 mmHg, P = 0.015). Responders were upgraded by means of an LV lead via the coronary sinus in the posterior (n = 1) or posterolateral (n = 4) walls and after attaining a high LV pacing threshold with an epicardial LV lead on the anterior (n = 1) or anterolateral (n = 1) walls. NYHA class improved from 3 to 2+/-0.3 (P = 0.003) during 204+/-120 days follow-up and cardiac output increased from 4.4+/-1.5 to 5.6+/-1.7 l/min (P = 0.027) when comparing BV pacing and optimal AV delay with RV pacing. In five nonresponders, PP was not higher during transoesophageal LV pacing than during RV pacing. CONCLUSION: Transoesophageal LV pacing may be a useful technique to detect responders to BV pacing in permanently RV-paced HF patients.     

Effect of biventricular pacing on heart rate variability in patients with chronic heart failure

BACKGROUND: Biventricular pacing is emerging as a long-term therapy for symptomatic heart failure. Analysis of heart rate variability (HRV) has become an important predictive tool in this syndrome. AIM OF THE STUDY: To assess whether chronic resynchronization therapy can affect HRV in patients with heart failure. METHODS AND RESULTS: Thirteen patients with heart failure were studied (mean age+/-1 S.E. 65+/-2.2 years, QRS 195+/-5.3 ms, NYHA class 3.2+/-0.1, LVEF 21+/-1.7%). The protocol included a preliminary no pacing period for 1 month following device implantation. Twenty-four hour Holter ECG recordings were performed at the end of this period (baseline) and after 3 months of biventricular stimulation (VDD mode). Prior to and following pacing patients underwent NYHA class evaluation, 6-min walk test, Quality of Life Assessment and a cardiopulmonary exercise test. Biventricular pacing improved functional class (P<0.0001) and Quality of life (P<0.0001), increased 6-min walk distance, (P=0.008) and exercise duration (P<0.0001) but had no significant effect on peak exercise VO(2). Resynchronization therapy increased mean 24-h RR (922+/-58 vs. 809+/-41 ms at baseline, P=0.006), SDNN (111+/-11 vs. 83+/-8 ms, P=0.003), SDNN-I (56+/-10 vs. 40+/-5 ms, P=0.02), rMSSD (66+/-14 vs. 41+/-8 ms, P=0.003), Total Power (5724+/-1875 vs. 2074+/-553 ms(2), P=0.03), Ultra Low Frequency Power (1969+/-789 vs. 653+/-405 ms(2), P=0.03) and Very Low Frequency Power (2407+/-561 vs. 902+/-155 ms(2), P=0.004). CONCLUSION: Biventricular pacing in heart failure improves autonomic function by increasing HRV. This may have important prognostic implications.     

Six year experience of transvenous left ventricular lead implantation for permanent biventricular pacing in patients with advanced heart failure: technical aspects

BACKGROUND—Biventricular pacing has been proposed as an adjuvant to optimal medical treatment in patients with drug refractory heart failure caused by chronic left ventricular systolic dysfunction and intraventricular conduction delay.OBJECTIVE—To assess the technical feasibility and long term results (over six years) of transverse left ventricular pacing with the lead inserted into a tributary vein of the coronary sinus.SUBJECTS—From August 1994 to February 2000, left ventricular lead implantation was attempted in 116 patients who were eligible for biventricular pacing (mean (SD) age 67 (9) years, New York Heart Association (NYHA) functional class III/IV, left ventricular ejection fraction 22 (6)%, QRS duration 185 (26) ms).RESULTS—The overall implantation success rate was 88% (n = 102). A learning curve was indicated by a progressive increase in success from 61% early on to 98% in the last year. The mean pacing threshold was 1.1 (0.7) V/0.5 ms at the time of implantation and increased slightly up to 1.9 (0.9) V/0.5 ms at the end of the follow up period (15 (13) months). The rate of acute and delayed left ventricular lead dislodgement decreased from 30% in the early years to 11% after 1999. During follow up, 19 patients required reoperation for delayed lead dislodgement or increase in left ventricular pacing threshold (n = 15), phrenic nerve stimulation (n = 3), or infection (n = 3).CONCLUSIONS—Transverse left ventricular pacing through the coronary sinus is feasible and safe. The rate of implantation failure and of lead related problems has decreased greatly with increasing experience and with improvements in the equipment.     

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.     

三腔双心室起搏治疗20例充血性心力衰竭患者的近期临床效果

目的 观察三腔双心室同步起搏治疗充血性心力衰竭的临床效果。方法 充血性心力衰竭伴心室内阻滞患者20例,男性16例,女性4例,平均年龄54.7岁。心功能均在Ⅲ-Ⅳ（NYHA分级）,体表心电图平均QRS时限为142.6ms。患者均进行了三腔双心室同步起搏,起搏电极导线分别置于右心房、右心室以及经由冠状静脉窦置于一支心脏静脉起搏左心室。观察双心室起搏前后左心室射血分数变化以及体表心电图QRS波变化。结果 双心室同步起搏后,患者心功能得到明显改善,左心室射血分数（left ventricular ejection fraction,LVETF)从24.4%提高至32.1%,左心室充盈时间延长,二尖瓣返流量减少,心功能从Ⅲ-Ⅳ级改善至Ⅱ-Ⅲ级,QRS时限由术前的142.6ms缩短至124.8ms。结论 初步临床观察提示,三腔双心室同步起搏可有效改善充血性心力衰竭伴心室内阻滞患者的心功能。     

Impact of left ventricular epicardial and biventricular pacing on ventricular repolarization in normal-heart individuals and patients with congestive heart failure.

AIMS: Malignant ventricular arrhythmias can arise in a subset of congestive heart failure (CHF) patients after they undergo cardiac resynchronization therapy (CRT), thus counteracting the haemodynamic benefits typically associated with biventricular pacing. This study seeks to assess whether alteration of the ventricular transmural repolarization and conduction due to reversal of the depolarization sequence during epicardial or biventricular pacing facilitate the development of ventricular arrhythmias. METHODS AND RESULTS: ECGs and monophasic action potential (MAP) were recorded during programmed stimulation from right ventricle (RV) endocardium (RV-Endo), left ventricle (LV) epicardium (LV-Epi), or both (biventricular, Bi-V) in 15 individuals without structural heart diseases. In patients with severe CHF and CRT (n=21), ECGs were collected during RV-Endo, LV-Epi, and Bi-V pacing. MAP duration on intracardiac electrogram, the QT, JT, and T(peak)-T(end) intervals on ECGs at different pacing sites were measured and compared. In subjects with or without structural heart disease, compared with RV-Endo pacing, LV-Epi and Bi-V pacing resulted in a longer JT (341.78+/-61.97 ms with LV-Epi, 325.86+/-59.69 ms with Bi-V vs. 286.14+/-38.68 ms with RV-Endo in CHF individuals, P<0.0001) or T(peak)-T(end) interval (121.55+/-19.88 ms with LV-Epi, 117.71+/-42.63 ms with Bi-V vs. 102.28+/-12.62 ms with RV-Endo in normal-heart subjects, P<0.0001; 199.70+/-62.44 ms with LV-Epi, 184.89+/-74.08 ms with Bi-V vs. 146.41+/-31.06 ms with RV-Endo in CHF patients, P<0.0001), in addition to prolonged myocardial repolarization time and delayed endocardial activation. During follow-up, sudden death and arrhythmia storm occurred in two CHF patients after CRT. CONCLUSION: Epicardial and biventricular pacing prolong the time and increase the dispersion of myocardial repolarization and delay the transmural conduction. All of these should be considered as potential arrhythmogenic factors in CHF patients who receive CRT.     

单纯左室起搏与双心室起搏治疗慢性心力衰竭的疗效比较

目的比较单纯左室起搏与双心室起搏治疗慢性心力衰竭(CHF)的可行性及临床效果。方法选择窦性心律、NYHA心功能分级Ⅲ~Ⅳ级、左室射血分数(LVEF)≤0.35、QRS波时限≥120 ms的CHF患者36例,成功植入心脏再同步化(CRT)起搏器后,随机分为两组,第一组先以右房左室起搏模式治疗(LV起搏模式)7天,然后以右房双室起搏模式治疗(Biv起搏模式)7天;第二组先以Biv治疗7天,然后以LV治疗7天。收集术前、术后第7天、第14天的临床资料,所有数据应用交叉设计资料方差分析及单变量一般线性模型分析。结果 6 min步行距离、明尼苏达生活质量评分、体表心电图QRS波时限、左室舒张末期内径、左室射血分数、左室间隔部与侧壁基底段收缩期达峰时间差值等6种评价指标的结果相似:评价指标测量值在处理效应即LV、Biv两种起搏模式上、在顺序效应即两种起搏模式顺序上的差异均无统计学意义(P均>0.05);但在阶段效应即术后第7天、第14天两阶段上的差异有统计学意义(P<0.05)。结论单纯左室起搏与双心室起搏治疗CHF的疗效相仿;对窦性心律、完全性左束支传导阻滞的CHF患者,单纯左室起搏可作为CRT的一种选择。