Echocardiographic aspects of multisite pacing in patients undergoing cardiac resynchronization therapy

BACKGROUND: Echocardiography has emerged as an accepted approach to define dyssynchrony in patients with advanced stage of heart failure (HF). Unfortunately no single echocardiographic parameter has been established to predict positive response after cardiac resynchronization therapy (CRT) and the nonresponder rate of 20-30% is still a matter of discussion and research. One of the most promising techniques in this regard is two-dimensional strain echocardiography based on speckle tracking with the potential to disclose residual dyssynchrony after primary CRT. An important reason for weak response to CRT is suboptimal position of the coronary sinus (CS) lead. Initial clinical benefit after CRT may mask partial residual dyssynchrony, which may cause worsening and recurrence of HF symptoms over time. Echocardiography helps to define the location of residual dyssynchrony and may identify patients who would benefit from implantation of a second CS-lead and triple-site pacing. If primary CRT fails due to imperfect placement of the CS-lead or due to coronary vein abnormalities and an epicardial approach is not appropriate, dual site pacing of the right ventricle may be an alternative procedure.     

Avoidance of right ventricular pacing in cardiac resynchronization therapy improves right ventricular hemodynamics in heart failure patients

Background: Cardiac resynchronization therapy (CRT) applied by pacing the left and right ventricles (BiV) has been shown to provide synchronous left ventricular (LV) contraction in heart failure patients. CRT may also be accomplished through synchronization of a properly timed LV pacing impulse with intrinsically conducted activation wave fronts. Elimination of right ventricular (RV) pacing may provide a more physiological RV contraction pattern and reduce device current drain. We evaluated the effects of LV and BiV pacing over a range of atrioventricular intervals on the performance of both ventricles.
Methods: Acute LV and RV hemodynamic data from 17 patients with heart failure (EF = 30 ± 1%) and a wide QRS (138 ± 25 msec) or mechanical dyssynchrony were acquired during intrinsic rhythm, BiV, and LV pacing.
Results: The highest LV dP/dt_max was achieved during LV pre- (LV paced prior to an RV sense) and BiV pacing, followed by that obtained during LV post-pacing (LV paced after an RV sense) and the lowest LV dP/dt_max was recorded during intrinsic rhythm. Compared with BiV pacing, LV pre-pacing significantly improved RV dP/dt_max (378 ± 136 mmHg/second vs 397 ± 136 mmHg/second, P < 0.05) and preserved RV cycle efficiency (61.6 ± 14.6% vs 68.6 ± 11.4%, P < 0.05) and stroke volume (6.6 ± 4.4 mL vs 9.0 ± 6.3 mL, P < 0.05). Based on LV dP/dt_max, the optimal atrioventricular interval could be estimated by subtracting 30 msec from the intrinsic atrial to sensed RV interval.
Conclusions: Synchronized LV pacing produces acute LV and systemic hemodynamic benefits similar to BiV pacing. LV pacing at an appropriate atrioventricular interval prior to the RV sensed impulse provides superior RV hemodynamics compared with BiV pacing.     

CRT 起搏心电图的分析与诊断

心脏再同步化治疗（cardiac resynchronization therapy,CRT）已经成为慢性心力衰竭伴心室不同步的Ⅰ类适应证,临床上 CRT 起搏心电图大量增加。在 CRT 起搏心电图分析和诊断中,必须掌握以下特点：①左右心室单独起搏的心电图特点;②窦性心律下,房室顺序和心室顺序起搏的心电图特点;③异位心律下 CRT 起搏心电图的特点;④ CRT 起搏器的特殊功能。     

右室感知触发左室起搏心脏再同步化治疗慢性充血性心力衰竭

目的探讨右室感知触发左室起搏心脏再同步化治疗(CRT)慢性充血性心力衰竭(CHF)的效果。方法植入三腔起搏器进行心脏超声优化的CHF患者30例,分别测定传统CRT优化后及右室感知触发左室起搏CRT模式的左室射血分数(LVEF)、舒张期二尖瓣血流速度时间积分(MVI)、二尖瓣返流VTI(MR-VTI)、主动脉瓣前向血流VTI(AVI),并与CRT术前及传统CRT右室优先模式(11例)比较上述心脏超声指标、QRS波时限、优化耗时及CRT费用的差别。结果右室感知触发左室起搏模式的平均电池寿命长于传统CRT模式,QRS波时限、优化耗时及CRT年平均费用少于传统CRT模式(均P<0.01);AVI、LVEF、MVI、MR-VTI与传统CRT模式无差异(均P>0.05),但与传统CRT模式高度相关(P<0.01)。右室感知触发左室起搏模式的AVI、LVEF、MVI较右室优先模式增加,MR-VTI较右室优先模式减少(P均<0.05)。结论右室感知触发左室起搏较右室优先的传统CRT模式改善CHF患者的血流动力学,降低CRT年平均费用。     

Mortality of heart failure patients after cardiac resynchronization therapy: identification of predictors

Introduction: A direct comparison of survival benefits between cardiac resynchronization therapy‐pacemaker (CRT‐P) and defibrillator (CRT‐D) was not yet performed, leaving clinicians to question whether CRT‐P alone is enough to protect congestive heart failure (CHF) patients from sudden cardiac death and whether CRT‐D should be implanted to all CHF patients indicated for biventricular pacing. This study attempts to make this type of comparison in a large CHF population and seeks to identify predictors of death in patients with different comorbidities. Methods and Results: Study population consisted of 542 consecutive patients who were implanted with either CRT‐P (N = 147) or CRT‐D (N = 395) between 1999 and 2005. Patients' clinical and follow‐up data were entered in a prospective registry and retrieved for analysis. The primary endpoint of this study was all‐cause mortality during follow‐up. Total all‐cause mortality was significantly lower among patients with CRT‐D (18.5% vs. 38.8% of CRT‐P, χ²= 25.11, P < 0.001). Patients with one of three comorbidities—chronic renal failure (OR = 4.885, P = 0.005), diabetes mellitus (OR = 4.130, P = 0.003), and history of atrial fibrillation (OR = 1.473, P = 0.036)—appeared to have higher risk of death, while treatment with beta‐blocker (OR = 0.330, P = 0.002) or CRT‐D device (OR = 0.334, P = 0.003) seemed to be associated with lower mortality. Conclusions: Data from this nonrandomized study indicate that CRT‐D has additional survival benefits over CRT‐P. Given these findings, CRT‐D should be recommended to most CHF patients with indications for biventricular pacing. After CRT implant, chronic renal failure, diabetes mellitus, and history of atrial fibrillation are strong independent predictors of death.     

Hemodynamic effects of atrial septal pacing in cardiac resynchronization therapy patients

INTRODUCTION: Spontaneous or pacing-induced interatrial conduction delay may affect the outcome of heart failure patients treated with cardiac resynchronization therapy (CRT). The objective of this study was to evaluate the impact of the atrial pacing site (right atrial appendage, RAA; and low interatrial septum, LIS) during biventricular (BV) pacing on the left ventricular (LV) systolic function in candidates for CRT. METHODS AND RESULTS: Fifteen heart failure patients with left bundle branch block and LV ejection fraction < or =35% were enrolled. Electrodes were placed at the RAA, LIS, right ventricular apex, and LV free wall. A DDD protocol was tested, which consisted of 50 beats in AAI mode from the RAA followed by 50 beats in BV DDD mode with atrial pacing at the RAA (DDD_RAA) or at the LIS (DDD_LIS) at four AV delays. The average (+/-SD)%LV+dP/dtmax increase during DDD_RAA and DDD_LIS pacing with respect to baseline was 24 +/- 16% and 21 +/- 15%, respectively (P < 0.01), and average percentage change in aortic pulse pressure during DDD_RAA and DDD_LIS with respect to baseline (%PP) was 13 +/- 8% and 13 +/- 7% (ns). CONCLUSIONS: Our results show a significant hemodynamic improvement with both DDD_RAA and DDD_LIS biventricular pacing compared to AAI pacing. However DDD_LIS pacing was not superior to DDD_RAA pacing in acute hemodynamic responses.     

房间隔起搏在心脏再同步治疗中的应用

目的通过简单的超声多普勒方法评价房间隔起搏在心脏再同步治疗（CRT）中的效果。方法在23例行CRT治疗的患者中进行了超声多普勒测量，9例患者存在房间阻滞，心房起搏导线固定在房间隔，其余14例常规固定在右心耳。结果右心耳起搏组中心房间传导延迟时间（IAD）延长[（46±20）ms vs（53±23）ms，P〈0．05]，IAD和心室间传导延迟时间（IVD）的差异增大[（53±23）ms VS（40±17）ms，P〈0．05]，左机械房室延迟时间（LMAVD）和右机械房室延迟时间（RMAVD）的差异明显增加[（172±25）ms vs（210±32）ms，P〈0．001]。房间隔起搏后IAD明显减小[（34±12）ms VS（12±11）ms，P〈0．001]，IAD和IVD的差别减少[（12±11）ms VS（18±16）ms，P〉0．05]，LMAVD和RMAVD差异无统计学意义[（187±43）ms vs（182±50）ms，P〉0．05]。二尖瓣A峰速度时间积分在房间隔起搏后明显增加[（8．9±4．9）cm vs（13．0±4．0）cm，P〈0．001]。结论房间阻滞可以导致左心和右心房室收缩顺序的差异，房间隔起搏能纠正这种差异，增加二尖瓣舒张期充盈进一步改善心脏再同步治疗。     

心脏同步化治疗慢性心力衰竭疗效及临床经验总结

目的总结心脏同步化起搏治疗慢性心力衰竭的疗效及临床经验。方法回顾性分析接受再同步化治疗的26例慢性心力衰竭伴心室内传导延迟患者的临床资料,着重分析再同步化治疗的方法和疗效。结果患者均接受心脏再同步化治疗,年龄（57.0±11.6）岁,男22例（84.6%,22/26）,其中再同步化转复除颤器16例（62%,16/26）,非缺血性心肌病22例（85%,22/26）,9例（35%,9/26）有慢性房性心律失常,2例需外科植入左心室心外膜电极。心脏再同步化治疗后QRS波时限由（161±29）ms缩短为（137±15）ms,差异有统计学意义（P≤0.01）;患者心功能均有明显改善,心功能分级比治疗前降低,差异有统计学意义[（1.9±0.9）级vs.（3.2±0.6）级,P≤0.01];射血分数比治疗前提高,差异有统计学意义（34.0%±13.3%vs.24.9%±6.8%,P≤0.01）。6分钟步行距离、血清脑钠肽浓度以及左心室舒张或收缩末内径均有显著改善（P≤0.05）。术后随访（2.5±1.7）年,7例（27%,7/26）死亡,其中2例心源性猝死。结论心脏同步化起搏治疗显著改善慢性心力衰竭患者心功能,逆转心肌重构,减低病死率。     

Depression and severe heart failure: benefits of cardiac resynchronization therapy

Depression and Cardiac Resynchronization Therapy . Background: The relationship between depression and heart failure is neither coincidental nor trivial, since depression is a powerful predictor of re‐hospitalization and mortality. We prospectively studied the prevalence and impact of depression on the clinical outcomes of patients attending for cardiac resynchronization therapy (CRT). We specifically examined whether patients with depression have a different rate of response to CRT and whether CRT has an effect on depressive symptoms. Methods: Sixty‐eight recipients of CRT systems were included. The depressive status was evaluated before implant and after 6 months by a structured diagnostic interview measuring Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV) criteria of major depression and by a self‐report questionnaire (Center for Epidemiological Studies Depression Scale, CES‐D). The CRT response was assessed at 6 months by a clinical composite score. Results: At inclusion, DSM‐IV criteria of major depression were identified in 41% of the population, while using the self‐report questionnaire 65% were observed to have mild to major depressive symptoms (CES‐D ≥ 16). Only 4 patients were taking antidepressants. At 6 months, 75% were considered responders to CRT. Response to CRT did not differ between those with and without depression at baseline. The rate of patients with depression at 6 months was significantly lower in responders to CRT compared with nonresponders. Conclusions: We found a high prevalence of depressive symptoms in patients receiving CRT systems. Patients with depression should not be excluded from CRT, because they demonstrate a similar rate of response than the persons without depression and the responders are less likely to be depressed at 6 months. (J Cardiovasc Electrophysiol, Vol. 23, pp. 631–636, June 2012)     

心脏再同步化治疗慢性心衰的临床观察

目的观察心脏再同步化治疗(CRT)慢性心力衰竭(CHF)患者的临床疗效。方法选择2008年1月至2009年8月行CRT的患者32例,其中12例植入再同步心脏转复除颤器(CRT-D)。32例中30例为窦性心律,2例为房颤心律。随访21.5±6.2个月,观察患者NYHA心功能分级、QRS波时限、左室射血分数(LVEF)、左室舒张末内径(LVEDD)、6分钟步行距离(6MWD)、因心功不全住院时间等。结果 32例植入CRT(D)患者中,有24例临床症状明显改善,心功分级降低,LVEF和6MWD增加,QRS波时限、LVEDD减少,因心功不全住院时间明显减少约24.5%(p<0.05)。8例患者心功能没有明显改善,但因心功不全住院时间减少约8.3%(p<0.05)。4例患者记录到室性心律失常事件(12.5%),2例室速经抗心动过速起搏(ATP)有效转复,2例患者因室颤而放电,均成功转复,CRT-D均能有效识别和转复。结论 CRT可明显改善CHF患者的心功能,提高生活质量,缓解临床症状,植入CRT-D可有效预防心源性猝死(SCD)。     

心脏再同步治疗慢性心力衰竭的临床疗效

目的观察心脏再同步治疗慢性心力衰竭的临床疗效。方法36例慢性心力衰竭合并室内传导阻滞的患者行双心室再同步起搏治疗。全部患者均经冠状静脉窦植入左心室导线至心脏静脉。治疗后随访12个月,观察心功能,6min步行距离,QRS波宽度,心室间运动延迟,左心室收缩、舒张末内径,左心室射血分数,二尖瓣反流面积。结果31例治疗后心功能改善,有效率86．1％（31／36）。心功能从Ⅲ～Ⅳ级（纽约心脏协会心功能分级）改善为Ⅱ～Ⅲ级;6min步行距离从（362±153）m提高至（528_＋165）m,差异有统计学意义（P〈0．01）;QRS波从（164．74±33．76）ms缩短至（129．45±42．27）ms,差异有统计学意义（P〈0．01）;心室间运动延迟时间从（65．19±21．50）ms缩短至（33．25±13．62）ms,差异有统计学意义（P〈0．01）;左心室舒张末内径从（66．52±10．23）mm缩小至（60．63±9．97）mm（P〈0．05）,左心室收缩末内径从（55．73±10．62）mm缩小至（47．45±11．35）mm,差异有统计学意义（P〈0．01）;左心室射血分数从30．35％±4．69％提高至42．27％±8．40％,差异有统计学意义（P〈0．01）;二尖瓣反流面积从（7．52±3．62）cm2减少至（4．33±2．07）cm2,差异有统计学意义（P〈0．01）。结论心脏再同步治疗是治疗慢性心力衰竭的有效方法,能使心脏活动再同步化,改善心功能。     

Sustained benefit of cardiac resynchronization therapy

Introduction: Most data on cardiac resynchronization therapy (CRT) are from trials with highly selected patients, with limited long-term echocardiographic data. This study was performed to evaluate long-term echocardiographic remodeling after CRT in daily practice.
Methods and Results: A biventricular pacemaker was implanted in 130 patients with advanced heart failure who met the general accepted criteria for CRT or in heart failure patients with a conventional pacemaker indication. Two years echocardiographic follow-up was available. Mean age (73 years) was higher than in the randomized trials. Forty-one patients (32%) died during the 2 year follow-up period. Mortality was higher in males, in patients with increased NT-proBNP, renal dysfunction, or left atrial dilatation before implantation. Echocardiographic response (LVEF improvement of 5% or more) was documented in 69, 88, and 91% of the survivors, after 3 months, 1 year, and 2 years, respectively. Echocardiographic response after 3 months was associated with a significantly higher long-term survival (P = 0.04). Mean LVEF was 22% at baseline compared to 31.8, 38.3, and 39.7% after 3 months, 1 year, and 2 years, respectively (P < 0.01). Reverse remodeling (a reduction of LV end systolic volume of more than 10%) was observed in 70.7, 81.0, and 91.7% of the survivors after 3 months, 1 year, and 2 years, respectively. Long-term LV improvement was more pronounced in patients with nonischemic cardiomyopathy.
Conclusion: LV reverse remodeling and beneficial echocardiographic changes were sustained during 2 years follow-up. A 5% or more increase in LVEF after 3 months was associated with a better long-term survival.     

Electrocardiographic versus echocardiographic optimization of the interventricular pacing delay in patients undergoing cardiac resynchronization therapy

Electrocardiographic VV Optimization. Introduction: Echocardiographic optimization of the VV interval may improve CRT response, but it is time‐consuming and not routinely performed. The aim of this study was to compare the response to cardiac resynchronization therapy (CRT) when the interventricular pacing (VV) interval was optimized by Tissue Doppler Imaging (TDI) to CRT response when it was optimized following QRS width criteria. Methods and Results: The study included 156 consecutive CRT patients with severe heart failure and left bundle‐branch block configuration. Atrioventricular interval was selected according to a pulsed Doppler assessment, and VV optimization was randomly assigned to echocardiography (ECHO group, n = 78) or electrocardiography (ECG group, n = 78). Optimal VV was defined for the ECHO group as producing the best LV intraventricular synchrony according to TDI displacement curves and for the ECG group as resulting in the narrowest QRS measured from the earliest deflection. At 6‐month follow‐up, percentage of echocardiographic responders (defined as neither death nor heart transplantation and a LV end‐systolic volume reduction >10%) was higher in the ECG optimized group (50.0% vs 67.9%; P = 0.023), whereas clinical response (defined as neither death nor heart transplantation and >10% improvement in the 6‐minute walking test) was similar in both groups (71.8% vs 73.1%; P = 0.858). Conclusions: VV optimization based on QRS width obtained a higher percentage of responders in terms of LV reverse remodeling compared to the TDI method. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1129‐1134, October 2011)     

Optimization of pacing intervals in cardiac resynchronization therapy

In patients with heart failure, left ventricular systolic dysfunction and prolonged QRS complex, cardiac resynchronization therapy (CRT) is a treatment method aimed at restoration of myocardial depolarization synchronicity. However, the extent of clinical and echocardiographic improvement depends on anatomical relations in individual patients, on structural changes in the heart, on intrinsic electrical activation, and on the position of pacing leads. Many parameters of CRT devices may be changed in order to tailor the function of CRT to the needs of a particular patient; the most important among them is AV and VV interval. The largest trials studying CRT used various methods for optimization of these intervals but unequivocal proof of the benefit brought by optimization is still lacking. Many methods were evaluated, most frequently based on echocardiography and intracardiac electrogram interval measurement. However, drawbacks in statistics make the studies of limited value for establishing a reference method or guidance for daily practice. Echocardiography has inherent variability of results and is highly operator dependent. Optimization based on intracardiac electrogram intervals has not proved yet to be of clear benefit above arbitrary AV interval. The most promising method is hemodynamic assessment by finger plethysmography. Measured data are highly reproducible and operator-independentA randomized multicenter double-blind study using finger plethysmography is needed to prove the value of this method and of CRT optimization in general. The measurement of information content in any data suitable for CRT optimization, analysis of reproducibility and general usage of confidence intervals may show other methods appropriate for it, too. The cooperation with a statistician is oftentimes a necessity.     

Right ventricular versus biventricular antitachycardia pacing in the termination of ventricular tachyarrhythmia in patients receiving cardiac resynchronization therapy: the ADVANCE CRT-D trial

BACKGROUND: The purpose of this investigation is to compare the efficacy of antitachycardia pacing (ATP) delivered via the right ventricular (RV) lead versus ATP delivered simultaneously via the right and left ventricular leads (biventricular [BiV]) in the termination of ventricular tachyarrhythmia (VT) in patients receiving cardiac resynchronization therapy (CRT) with ICD capabilities. METHODS AND RESULTS: The ADVANCE CRT is a prospective, multicenter, randomized, parallel trial evaluating RV versus BiV ATP in the termination of VT in CRT patients. The study will test the hypothesis that BiV ATP is superior to RV ATP in the termination of VT and fast VT. All patients with class I and IIa indications for an ICD implantation and CRT are included. The sample size has been estimated to 400 participants followed for 12 months to show a 10% benefit of BiV versus RV ATP. The efficacy of BiV ATP to terminate all VT presents the primary endpoint. The investigation is expected to be completed in 2007. CONCLUSIONS: The ADVANCE CRT trial is the first large randomized clinical investigation evaluating the efficacy of BiV ATP in patients under CRT and ICD therapy.     

心脏再同步化治疗对充血性心力衰竭患者内皮功能的影响

目的:探讨心脏再同步化治疗(CRT)对充血性心力衰竭(心衰)患者内皮功能的影响。方法:扩张型心肌病并发心衰患者分为药物治疗组(10例)和CRT+药物治疗组(12例),分别在治疗前、治疗12周末,检测心脏超声、血管内皮功能、脑钠肽(BNP)。结果:与药物治疗组比较,CRT+药物治疗组明显增加患者的心脏输出量[(4.32±1.50)L/min∶(3.41±1.00)L/min,P<0.05]及肱动脉内径的变化率(FMD)[(1 718±123)%∶(976±118)%,P<0.05],FMD和心输出量呈正相关(r=0.6,P=0.003)。结论:CRT可以提高内皮细胞的功能,其机制可能是通过增加心输出量来实现的。     

心脏再同步治疗中重度心力衰竭的疗效及无应答原因分析

目的:通过对置入三腔起搏器的中重度心力衰竭患者进行随访观察,分析心脏再同步治疗(CRT)的临床疗效及对CRT无应答的原因.方法:24例慢性充血性心力衰竭患者,心功能Ⅲ～Ⅳ级(NYHA分级),其中扩张型心肌病18例,缺血性心肌病2例,致密化不全心肌病2例,病态窦房结综合征已置入双腔起搏器1例,Ⅲ度房室传导阻滞已置入单腔起...     

单中心心脏再同步治疗的长期病死率及原因分析

目的观察本中心心脏再同步治疗（CRT）的长期病死率,分析可能的相关因素。方法2001年3月至2010年4月135例患者行CRT治疗,男106例,平均年龄（59．95±11．14）岁。缺血性心肌病（ICM）44例,心功能Ⅲ～Ⅳ级（NYHA分级）,LVEF≤0．35。随访最长9年。结果全因死亡率为31．11％,其中心力衰竭占26．19％,猝死占38．1％。与存活患者比较,心力衰竭恶化死亡患者更年轻、CRT治疗前的临床指标差、肺动脉压高、左心室舒张末内径增大明显（P〈0．05）,而且PR间期明显延长（P〈0．05）,不理想的左心室电极导线位置（心中静脉和心大静脉）的比例增加（P〈0．01）。非心力衰竭死亡组CRT治疗后心功能的各项指标及活动耐量均改善,且随着时间延长改善更明显,而心力衰竭死亡组随着时间延长病情反复且加重。结论本中心CRT长期治疗的全因死亡率为31％,死亡原因中心脏性猝死发生率最高,心力衰竭恶化排第2位,经CRT后因心力衰竭和猝死导致的死亡率低于以前药物治疗（20％／4年和〉50％／5年）。对于心功能好转的患者预防猝死是重要的,心脏再同步治疗除颤器（CRT－D）应是首选治疗。     

Prognostic effects of pulmonary hypertension in patients undergoing cardiac resynchronization therapy

Background

Aim of this study is to investigate the impact of elevated pulmonary artery systolic pressure (PASP) on mortality and the clinical outcome after cardiac resynchronization therapy (CRT).

Methods

Ninety-three patients with heart failure were enrolled into this study, and all of them have been treated by CRT for more than 6 months. Based on the level of preoperative PASP, they were divided into three groups (Group I: PASP>50mmHg, n=29; Group II: 30mmHgResults①Eight (28%), one (6%) and eight (17%) patients died in-group I, II and III respectively. Among those patients, 5 in group I and 1 in group III died of heart failure, while the patient in group II died of sudden death. ②In all three groups, CRT significantly improved heart function evaluated by NYHA heart function class and 6 minutes walking distance (6-MWT) (P<0.01). The improvement was more significant in group III than group I (P<0.01). ③At 3 months after CRT, Left ventricular ejection fraction (LVEF) increased significantly in Group III (P<0.01), but not in Group I or II (all P>0.05. At 6 months after CRT, LVEF increased significantly in all three groups (all P<0.05).

Conclusions

Elevated PASP has no prognostic effects on heart function improvement in patients undergone CRT. However, it was associated with worse LV remodeling and increased death due to aggravation of heart failure.