失同步心力衰竭与再同步治疗的动物模型

动物模型可用来模拟失同步心力衰竭（DHF）发生发展与心脏再同步治疗（CRT）作用的病理生理过程,对深入探索DHF和CRT的机制具有重要意义。传统的模型以犬类等大型哺乳动物为主,近年来随着技术的进步,用小鼠及大鼠建立DHF和CRT模型的方法也逐渐涌现。本文复习相关文献,对多种DHF和CRT的动物模型制作方法进行综述。     

心脏再同步治疗对心肌纤维化的影响

目的:本文通过观察心肌病患者CRT手术前后I型前胶原氨端肽(P-INP)、Ⅲ型前胶原羧基端肽(P-ⅢCP)和IV型胶原(IV-C)的血清浓度的变化以及与心衰的关系,初步探讨其与CRT对心肌纤维化的影响.方法:选择2009年1月-2009年8月行CRT的患者(CRT组),另选择与上述患者同期住院年龄相近的患者作为对照组....     

心脏再同步治疗心力衰竭的研究进展

心脏再同步治疗的适应证不断拓宽,但即使按指南建议选择患者,仍有部分患者对治疗无反应,本文就心脏再同步治疗适应证的进展及可能的疗效预测指标做一综述。     

心力衰竭的进展(13)慢性心力衰竭心脏再同步治疗研究进展(续8)

慢性心力衰竭患者常伴随的QRS波增宽和心脏不同步进一步加重病情。心脏再同步治疗(CRT)可以部分纠正心脏不同步、改善心功能、提高生活质量、降低病死率。本文回顾了CRT的重要研究和指南,介绍了CRT的患者选择、相关临床情况治疗决策的依据和建议,并展望了CRT未来的发展前景。     

心脏再同步治疗心力衰竭最新研究进展

心脏再同步治疗是一种非药物治疗心力衰竭的新方法。多项临床研究已证实,心脏再同步治疗可以显著改善患者的心功能,提高生活质量,减少患者的病死率及再住院率。     

心脏再同步治疗慢性心力衰竭的中远期疗效观察

目的观察双心室再同步起搏治疗慢性心力衰竭(CHF)的临床疗效。方法28例慢性心力衰竭合并室内阻滞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1根至心脏静脉,术后平均随访20.6个月,观察心功能,QRS波宽度,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24例患者治疗后心功能改善,有效率85.7%,心功能从Ⅲ~Ⅳ级(NYHA分级)改善为Ⅱ~Ⅲ级,QRS波从(160±58)ms缩短至(132±53)ms,P<0.05,左心室舒张末内径、收缩末内径分别从(73.54±9.96)mm、(64.25±11.32)mm缩小至(68.75±8.63)mm和(58.51±10.78)mm,P<0.01,左心室射血分数从0.23±0.09提高至0.32±0.10,P<0.01,二尖瓣反流面积从(8.03±4.27)cm2减少至(5.15±4.02)cm2,P<0.01。结论双心室再同步起搏是慢性心力衰竭治疗的有效方法。     

心肌组织多普勒在心脏再同步治疗中的应用

心脏再同步治疗（cardiac resynchronization therapy,CRT）,作为一种慢性心力衰竭（CHF）患者非药物治疗的方法,其疗效已不断被临床研究所证实,并已逐渐成为特定CHF患者的Ⅰ线疗法.对于这类心室不同步的CHF患者,CRT可改善症状和生活质量,减少并发症及死亡危险.2005年的ACC/AHA和ESC慢性CHF诊治指南已将其列入Ⅰ类指征.而心肌组织多普勒,因其无创性、高空间和时间分辨率以及可定量分析等特点,在探讨CRT治疗的作用机制,选择合适的患者,优化起搏程序,评价和随访疗效方面具有独特的作用.     

心脏再同步治疗对轻至中度心力衰竭患者心功能的影响

目的探讨心脏再同步治疗(cardiac resynchronization therapy,CRT)对轻至中度心力衰竭患者心功能改善的影响。方法回顾性分析9例植入CRT或CRT除颤器(CRT-defibrillator,CRT-D)患者资料,观察和分析其纽约心脏协会(New York Heart Association,NYHA)心功能分级、左心室射血分数、左心室舒张末期内径、QRS间期和血浆脑钠肽浓度的变化。结果9例患者随访时间6～120个月,无手术相关的并发症。与基线资料相比,经CRT或CRT-D治疗后,患者的QRS时限明显变窄[125 ms(110～140 ms)vs.150 ms(130～180 ms),P=0.007],NYHA分级明显改善[(1.78±0.83)级vs.(2.56±0.53)级,P=0.043],左心室射血分数升高[42%(20%～50%)vs.30%(25%～35%),P=0.044],血浆脑钠肽浓度下降[85 pg/mL(35～890 pg/mL)vs.680 pg/mL(480～1 600 pg/mL),P=0.011],6分钟步行试验距离明显提高[560 m(150～620 m)vs.280 m(180～400 m),P=0.015],差异均有统计学意义。左心室舒张末期内径的改变无统计学意义[65 mm(56～82 mm)vs.55 mm(52～74 mm),P=0.172]。结论在规范化抗心力衰竭药物治疗的基础上,CRT或CRT-D治疗能够明显改善轻、中度心力衰竭患者的心功能。     

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。     

心力衰竭心脏再同步治疗的几个热点问题

<正>左心室、右心室同步起搏的心脏再同步治疗(cardiac resynchronization therapy,CRT),可以提高心力衰竭患者存活率,降低病死率,改善症状、生活质量、运动耐量和心功能[1]。无论是否同时置入心律转复除颤器(CRT-D),CRT均可降低心力衰竭人群病死率和死亡率[2]。因此,各种指南一致推荐,对最佳药物治疗无效的适宜心力衰竭患者,CRT无疑是其治疗的首要选择。大量证据支持心功能III级或非卧床的心功能IV级患     

Role of echocardiography in the assessment of mechanical dyssynchrony

The aim of this paper is to summarize the current scientific evidence regarding the prognostic implications of mechanical asynchrony, the benefits of identifying mechanical asynchrony prior to cardiac resynchronization therapy by means of echocardiography to predict response to cardiac resynchronization therapy and the different described parameters for dyssynchrony evaluation and measurement.     

Measuring left ventricular mechanical dyssynchrony from ECG-gated SPECT myocardial perfusion imaging

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. The traditional criteria to select patients for CRT (New York Heart Association [NYHA] class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) result in at least 30% of the selected patients with no response to CRT. Recent studies with echocardiography have shown that the presence of LV dyssynchrony is an important predictor for response to CRT. However, the recent report from the predictors of response to cardiac resynchronization therapy (PROSPECT) trial suggested that under 'real-world' conditions the current available echocardiographic techniques including tissue Doppler imaging (TDI) and myocardial strain-rate imaging are not ready for routine clinical practice to assess LV dyssynchrony. Phase analysis is a recently developed technique that allows measuring LV dyssynchrony from electrocardiogram (ECG)-gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). This technique uses Fourier harmonic functions to approximate regional wall thickening over the cardiac cycle and to calculate regional onset of mechanical contraction (OMC) phases. These OMC phases are obtained three-dimensionally over the entire left ventricle to quantitatively assess the degree of LV dyssynchrony. This technique has been compared to TDI and shown promising results in clinical validations. The advantages of this technique over echocardiography in measuring LV dyssynchrony are its automation, its high repeatability and reproducibility. It can be applied to any conventional GSPECT MPI study with no additional procedure. In this review the phase analysis methodology is described and its up-to-date clinical validations are summarized.     

Scintigraphic assessment of sympathetic innervation after transmural versus nontransmural myocardial infarction

To evaluate the feasibility of detecting denervated myocardium in the infarcted canine heart, the distribution of sympathetic nerve endings using I-123 metaiodobenzylguanidine (MIBG) was compared with the distribution of perfusion using thallium-201, with the aid of color-coded computer functional map in 16 dogs. Twelve dogs underwent myocardial infarction by injection of vinyl latex into the left anterior descending coronary artery (transmural myocardial infarction, n = 6), or ligation of the left anterior descending coronary artery (nontransmural myocardial infarction, n = 6). Four dogs served as sham-operated controls. Image patterns were compared with tissue norepinephrine content and with histofluorescence microscopic findings in biopsy specimens. Hearts with transmural infarction showed zones of absent MIBG and thallium, indicating scar. Adjacent and distal regions showed reduced MIBG but normal thallium uptake, indicating viable but denervated myocardium. Denervation distal to infarction was confirmed by reduced norepinephrine content and absence of nerve fluorescence. Nontransmural myocardial infarction showed zones of wall thinning with decreased thallium uptake and a greater reduction or absence of MIBG localized to the region of the infarct, with minimal extension of denervation beyond the infarct. Norepinephrine content was significantly reduced in the infarct zone, and nerve fluorescence was absent. These findings suggest that 1) MIBG imaging can detect viable and perfused but denervated myocardium after infarction; and 2) as opposed to the distal denervation produced by transmural infarction, nontransmural infarction may lead to regional ischemic damage of sympathetic nerves, but may spare subepicardial nerve trunks that course through the region of infarction to provide a source of innervation to distal areas of myocardium.     

Echocardiographic assessment of ventricular dyssynchrony

Although cardiac resynchronization therapy (CRT) has been of unquestioned therapeutic benefit to many patients with heart failure identified by a widened QRS complex on an electrocardiogram, many patients do not respond favorably. Several studies using echocardiographic methods to measure abnormalities of mechanical activation, known as dyssynchrony, have been proposed to improve patient selection for CRT. Many single-center studies from institutions with special expertise have demonstrated the feasibility of echocardiographic dyssynchrony to potentially assist with patient selection. However, the PROSPECT trial, a recent large multicenter study, highlighted the technical challenges in echocardiographic dyssynchrony analysis in mainstream clinical practice. Accordingly, a uniform clinical approach has not been established, and refinements of echocardiographic approaches and methods are constantly evolving. This article reviews current echocardiographic methods to quantify ventricular dyssynchrony, their strengths and limitations, and the proposed and potential expanding clinical applications.     

Feature-tracking cardiovascular magnetic resonance as a novel technique for the assessment of mechanical dyssynchrony

Background

Myocardial tagging using cardiovascular magnetic resonance (CMR) is the gold-standard for the assessment of myocardial mechanics. Feature-tracking cardiovascular magnetic resonance (FT-CMR) has been validated against myocardial tagging. We explore the potential of FT-CMR in the assessment of mechanical dyssynchrony, with reference to patients with cardiomyopathy and healthy controls.

Methods

Healthy controls (n = 55, age: 42.9 ± 13 yrs, LVEF: 70 ± 5%, QRS: 88 ± 9 ms) and patients with cardiomyopathy (n = 108, age: 64.7 ± 12 yrs, LVEF: 29 ± 6%, QRS: 147 ± 29 ms) underwent FT-CMR for the assessment of the circumferential (CURE) and radial (RURE) uniformity ratio estimate based on myocardial strain (both CURE and RURE: 0 to 1; 1 = perfect synchrony)

Results

CURE (0.79 ± 0.14 vs. 0.97 ± 0.02) and RURE (0.71 ± 0.14 vs. 0.91 ± 0.04) were lower in patients with cardiomyopathy than in healthy controls (both p < 0.0001). CURE (area under the receiver-operator characteristic curve [AUC]: 0.96), RURE (AUC: 0.96) and an average of these (CURE:RURE_AVG, AUC: 0.98) had an excellent ability to discriminate between patients with cardiomyopathy and controls (sensitivity 90%; specificity 98% at a cut-off of 0.89). The time taken for semi-automatically tracking myocardial borders was 5.9 ± 1.4 min.

Conclusion

Dyssynchrony measures derived from FT-CMR, such as CURE and RURE, provide almost absolute discrimination between patients with cardiomyopathy and healthy controls. The rapid acquisition of these measures, which does not require specialized CMR sequences, has potential for the assessment of mechanical dyssynchrony in clinical practice.     

Left ventricular mechanical dyssynchrony as assessed by phase analysis of ECG-gated SPECT myocardial perfusion imaging

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. The traditional criteria to select patients for CRT (NYHA class III or IV, depressed left ventricular (LV) ejection fraction, and prolonged QRS duration) result in at least 30% of the selected patients with no response to CRT. Recent studies with tissue Doppler imaging (TDI) have shown that the presence of LV dyssynchrony is an important predictor for response to CRT. Phase analysis has been developed to assess LV dyssynchrony from electrocardiography-gated single photon emission computed tomography (GSPECT) myocardial perfusion imaging (MPI). This technique uses Fourier harmonic functions to approximate regional wall thickening over the cardiac cycle and to calculate phases of regional onset of mechanical contraction (OMC). These OMC phases are obtained three-dimensionally over the left ventricle to generate an OMC phase distribution. Quantitative indices are calculated from the phase distribution to assess degree of LV dyssynchrony. This technique has been compared to other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review, the phase analysis methodology is described and its up-to-date validations are summarized.     

Assessment of left ventricular mechanical dyssynchrony by phase analysis of ECG-gated SPECT myocardial perfusion imaging.

Cardiac resynchronization therapy (CRT) has shown benefits in patients with severe heart failure. However, at least 30% of patients selected for CRT by use of traditional criteria (New York Heart Association class III or IV, depressed left ventricular [LV] ejection fraction, and prolonged QRS duration) do not respond to CRT. Recent studies with tissue Doppler imaging have shown that the presence of LV dyssynchrony is an important predictor of response to CRT. Phase analysis has been developed to allow assessment of LV dyssynchrony by gated single photon emission computed tomography myocardial perfusion imaging. This technique uses Fourier harmonic functions to approximate regional wall thickness changes over the cardiac cycle and to calculate the regional onset-of-mechanical contraction phase. Once the onset-of-mechanical contraction phases are obtained 3-dimensionally over the left ventricle, a phase distribution map is formed that represents the degree of LV dyssynchrony. This technique has been compared with other methods of measuring LV dyssynchrony and shown promising results in clinical evaluations. In this review the phase analysis methodology is described, and its up-to-date validations are summarized.