心力衰竭患者QRS波间期与心脏机械收缩功能失同步化的相关性研究

目的评价充血性心力衰竭(CHF)患者QRS间期与左右心室间、左心室内不同步运动参数的相关关系。方法 81例CHF患者及26名健康体检者作为对照组纳入本研究。行常规及彩色组织多普勒显像(TDI)检查。以左、右心室问收缩延迟(IVMD)>33ms定义室间不同步运动,以二尖瓣环6位点中任意2点QRS波起始至心室收缩顶峰的间期(TsP)最长延迟>121ms,或6位点TsP的标准差(TsP-SD)>47ms定义左心室内收缩不同步。比较QRS≥120 ms与QRS<120ms的CHF患者室间、室内不同步发生率,分析QRS间期与室间、室内不同步参数的相关关系。结果 CHF患者IVMD较对照组明显延长[(25.7±16.3)ms比(12.8±8.8)ms,P<0.0001],IVMD与QRS间期呈明显正相关(r=0.44,P<0.0001)。CHF伴QRS≥120ms(n=31)者室间不同步发生率明显高于CHF伴QRS<120ms者(n=50)(66.7%比20.9%,P<0.05)。CHF患者TsP最长延迟及TsP-SD较对照组明显延长,TsP最长延迟及TsP-SD与QRS间期呈弱相关。结论 CHF患者室间不同步运动发生率明显高于对照组,ORS间期增宽与室间不同步的关系可能更密切。     

有关缺血性心肌病心脏收缩同步性的研究

目的:探讨脉冲多普勒(PW)及组织同步成像技术(TSI)评价缺血性心肌病(ICM)患者心脏收缩的同步性的价值。方法:搜集ICM患者50例(ICM组),无器质性心脏病健康志愿者35例(健康对照组),分别用PW测量二尖瓣舒张期血流持续时间/RR间期(LVFT/RR)来评价左房、左室同步性;测量心室间机械延迟时间(IVMD)来评价左右室间同步性;用TSI软件测量二尖瓣环平均收缩峰速度(LV-Sm),收缩期达峰时间(Ts)及所有节段收缩期达峰时间的标准差(Ts-SD)来评价左室内收缩的同步性。结果:与健康对照组比较,ICM组LVFT/RR[(44.74±1.58)%比(41.08±4.65)%]、LV-Sm[(9.72±0.53)ms比(4.09±1.06)ms]显著降低,IVMD[(15.51±5.52)ms比(41.96±4.20)ms]、Ts-SD[(16.47±4.16)ms比(34.13±11.68)ms]显著增加,P均<0.01;前壁、下壁等6部位的Ts显著延长,且同步性显著降低;左室内收缩最延迟部位所占比例无显著差异(P>0.05)。结论:缺血性心肌病患者较健康对照组左室整体收缩功能明显减低,左房、左室,左右室间,左室内收缩同步性明显降低。     

应用超声多普勒评价不同QRS时限心力衰竭患者的收缩同步性

目的应用常规超声和组织多普勒技术评价收缩不同步在QRS时限正常及增宽的心力衰竭患者中的发生率。方法选择60例纽约心脏病学会(NYHA)分级心功能Ⅲ级的扩张型心肌病患者,其中QRS时限≤120ms者30例,QRS时限>120ms者30例,均接受常规超声和组织多普勒检查。以左、右心室射血前间期之差>40ms作为室间收缩不同步的指标。应用组织多普勒技术分别测量室间隔和左心室侧壁基底部心肌达到收缩峰值的时间,二者时差>60ms定义为室内收缩不同步。满足室间、室内收缩不同步标准任一项即视为存在收缩不同步。结果QRS时限≤120ms的心力衰竭患者中有23.3%存在收缩不同步,而QRS时限>120ms者中不同步比例高达86.7%,二者差异有统计学意义(P<0.01)。未发现QRS时限与超声证实的收缩不同步间存在相关性(P=0.112)。结论尽管QRS时限增宽心力衰竭患者的不同步比例很高,但仍有一定比例的患者同步性尚好。同时,亦有一定比例的QRS时限正常者存在收缩不同步。     

电生理标测冠状静脉窦分支最延迟电激动处植入左室导线行心脏再同步化治疗

目的探讨电生理标测冠状静脉窦(CS)分支最延迟电激动处植入左室导线行心脏再同步治疗(CRT)。方法 10例中重度心力衰竭患者,均满足NYHA心功能Ⅲ～Ⅳ级,左室射血分数(LVEF)<0.35且QRS波时限≥120 ms。CRT术中在可植入左室导线的CS分支内进行电生理标测,将标测的最延迟心室电激动处作为左室导线的植入部位,观察该方法的可行性及临床疗效。结果 10例中,扩张型心肌病7例,缺血性心脏病3例;7例为窦性心律,3例为心房颤动;9例ECG表现为左束支传导阻滞,1例为室内传导阻滞。对10例的28个可作为左室导线植入部位的CS分支进行了电生理标测,10例均成功将左室导线植入在标测的最延迟电激动处,该处局部电位较体表ECG的QRS波起始延迟116±28 ms。术后即刻QRS波时限为121±17 ms,比术前153±30 ms明显缩短,P<0.01。8例CRT术后随访时间超过3个月,均有CRT应答(8/8,100%),其中3例超应答(3/8,37.5%),另外1例缺血性心肌病患者CRT术后2个月死于急性前壁心肌梗死;8例CRT应答患者NYHA心功能分级、6 min步行距离、LVEF值、左室收缩末容积、二尖瓣返流速度均较术前明显改善(1.6±0.5级vs 3.3±0.5级;405±92 m vs 307±82m;0.42±0.06 vs 0.30±0.04;121±38 ml vs 153±44 ml;3.9±1.2 m/s vs 4.5±1.5 m/s,P均<0.01)。结论电生理标测指引CS分支最延迟电激动处植入左室导线的CRT方法可行且短期疗效明显。     

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。     

双腔起搏器术后患者室壁运动同步性分析

目的分析永久性起搏器植入术后右心室起搏患者的心室间及心室内非同步收缩的特点及影响因素。方法收集永久性起搏器植入术后的患者22例,分为右心室起搏组与对照组。应用定量组织多普勒技术获得患者左心室各节段心肌及右心室侧壁的组织多普勒速度曲线,分别测量各节段自QRS波起始至心肌收缩期峰值速度和舒张早期峰值速度的时限等收缩期同步性指标和舒张期同步性指标,以及运动速度峰值。结果右心室起搏组与对照组两组间可测得的组织多普勒参数左心室壁12个节段收缩期达峰时间[(188.3±46.0)ms比(142.6±33.3)ms]差异有统计学意义(P<0.05),表明在心室起搏组存在左心室壁收缩的延迟。但有关左心室壁12个节段内运动同步性的参数,左心室壁12个节段收缩期达峰时间的标准差[(29.9±18.7)ms比(30.3±20.3)ms]及左心室壁12个节段收缩期达峰时间最大与最小值的差值[(95.6±60.4)ms比(90.0±58.3)ms]两组间差异无统计学意义。结论常规右心室心尖起搏致QRS波增宽,可造成心室间收缩不同步,但不一定会造成左心室内收缩不同步。     

利用组织多普勒评价左束支阻滞患者心室内不同步

利用组织多普勒测量不同步指数评价左束支阻滞 (LBBB)患者心室内不同步 ,对 15例LBBB患者 (LBBB组 )和 15例正常人 (对照组 )左心室各壁基底、中间、心尖段 ,获取组织多普勒速度曲线 ,分别测量QRS波起点到S波起点的时间 (Q Sb) ,计算心室内同步性指数 (TSI)和各室壁壁内的同步性指数 (RSI)。结果 :LBBB组患者各壁Q Sb延长 ,以室间隔、前壁、下后壁显著 ;TSI和左室室间隔的RSI较对照组明显增高 (分别为 30 .86± 9.78msvs 14 .81± 6 .89ms;2 7.13± 16 .82msvs 12 .19± 10 .70ms ,P均 <0 .0 1)。结论 :LBBB时左室激动顺序异常 ,左室各壁各节段出现不同程度的收缩延迟 ,心室内不同步明显 ;同一室壁内的不同步 ,以室间隔最显著。     

QRS波时限鉴别宽QRS波心动过速

心电图的QRS波代表心室除极过程,其宽度也称QRS波时限。临床中,根据QRS波时限是否≥120ms,而将心动过速分为宽QRS波心动过速和窄QRS波心动过速。宽QRS波心动过速包括:室速、室上速伴差异传导或原有束支阻滞(或非特异性室内阻滞)、逆向型房室折返性心动过速、房颤伴旁路前传及起搏相关性心动过速等。其中,室速是宽QRS波心动过速的最常见原因,约占全部原因的80%,而仅5%的室速QRS波时限小于120ms。因而,     

急诊心律失常患者如何安全有效用药?

<正>答:急诊心律失常具有起病急、进展快、死亡率高的特点,大致可分为急诊快速性心律失常和急诊缓慢性心律失常。急诊快速性心律失常又可根据QRS波宽度分为窄QRS波心动过速(QRS波群时限≤120 ms)和宽QRS波心动过速(QRS波群时限>120 ms)。窄QRS波心动过速大多数为室上性心动过速。而宽QRS波心动过速多数为室性心动过速,10%为室上速伴室内差异性传导或预激。急诊医生在处     

组织追踪显像评估扩张型心肌病患者心肌收缩失同步化

目的探讨组织追踪成像(TTI)评价扩张型心肌病心力衰竭患者心肌收缩失同步化的价值.方法应用TTI分析19例扩张型心肌病但QRS间期无明显增宽的心力衰竭患者和23例正常人的左室壁运动位移曲线,测量QRS波起始至左室壁12个节段收缩期位移峰的时间并除以 R-R间期进行校正(Ts).计算最大Ts与最小Ts的差值(Ts-MD)及Ts的标准差(Ts-SD)和变异系数(Ts-CV)用以评估两组试验对象的心肌收缩同步性.结果扩张型心肌病心力衰竭患者各室壁收缩期峰位移均明显减低(P＜0.001),约57.9%的患者存在左室收缩失同步化,且最大收缩延迟部位亦不完全相同.结论左室收缩失同步化在QRS间期无明显延长的扩张型心肌病心力衰竭患者中亦常见,TTI能够评价左室收缩失同步化.     

Prevalence of cardiac dyssynchrony and correlation with atrio-ventricular block and QRS width in dilated cardiomyopathy: an echocardiographic study

Introduction

Cardiac dyssynchrony causes disorganised cardiac contraction, delayed wall contraction and reduced pumping efficiency. We aimed to assess the prevalence of different types of dyssynchrony in patients with dilated cardiomyopathy (DCM), and to establish the correlation between atrio-ventricular block and atrio-ventricular dyssynchrony (AVD), and between impaired intra-ventricular conduction and the existence of inter-ventricular dyssynchrony (inter-VD) and intra-left ventricular dyssynchrony (intra-LVD).

Methods

We included 40 patients in New York Heart Association stage III or IV, admitted consecutively with DCM with severe left ventricular dysfunction (left ventricular end-diastolic diameter ≥ 60 mm and/or ≥ 30 mm/m²) and left ventricular ejection fraction < 35%. Electrocardiographic and echocardiographic data were evaluated in all patients. Patients were divided into two groups: group 1: eight patients, with a QRS duration ≥ 120 ms, and all presented with left bundle branch block; group 2: 32 patients with a narrow QRS < 120 ms.

Results

Overall, the mean age was 54.7 ± 16.8 years and patients in group 1 were older (67.2 ± 13.6 vs 51.5 ± 15.8 years, p = 0.01). The prevalence of atrio-ventricular dyssynchrony (AVD), inter-VD and intra-LVD was respectively 40, 47.5 and 70%. Two patients (5%) did not exhibit dyssynchrony. AVD was present with a similar frequency in the two groups (37.5% in group 1 vs 40.6% in group 2, p = 0.8). There was no correlation of the magnitude of AVD with the duration of the PR interval (from the beginning of the P wave to the beginning of the QRS complex) (r² = 0.02, p = 0.37) or the QRS width (r² = 0.01, p = 0.38). A greater proportion of patients with inter-VD was observed in group 1 (87.5 vs 60%, p = 0.03). There was a trend towards a more important inter-ventricular mechanical delay according to QRS width (r² = 0.009, p = 0.06). The proportion of intra-LVD was similar in all groups, with a high prevalence (87.5% in group 1 and 65.6% in group 2, p = 0.39).

Conclusion

The assessment of cardiac dyssynchrony is possible in our country. Intra-ventricular mechanical dyssynchrony had a high prevalence in patients with DCM, irrespective of the QRS width. These data emphasise the usefulness of echocardiography in the screening of patients.     

Real Time Three‐Dimensional Echocardiographic Assessment of Left Ventricular Regional Systolic Function and Dyssynchrony in Patients with Dilated Cardiomyopathy

Purpose: To evaluate left ventricular (LV) regional systolic function and dyssynchrony in patients with dilated cardiomyopathy (DCM) by real time three‐dimensional echocardiography (RT‐3DE). Methods: The study population comprised 30 normal controls (NOR) and 44 patients with DCM. We divided the left ventricle into apical, middle, and basal regions. We calculated the LV regional end‐diastolic volume (_REDV), regional end‐systolic volume (_RESV), regional ejection fraction (_REF), and standard deviation in the time to minimal systolic volume in each level segment (Tmsv‐SD) of the three regions by RT‐3DE. Results: Compared with NOR, the _REDV, _RESV, and Tmsv‐SD of DCM were significantly higher, whereas the _REF was lower (P < 0.01). In DCM, the Tmsv‐SD increased smoothly from base to apex, and the _REF gradually decreased from base to apex (P < 0. 05). Linear correlation was observed between the Tmsv‐SD of the middle region and 3D‐EF in DCM (r =?0. 6829, P < 0.01). Conclusion: RT‐3DE provides a simple and feasible approach to quantify LV regional systolic function and dyssynchrony. (ECHOCARDIOGRAPHY 2010;27:415‐420)     

Filtered QRS duration on signal-averaged electrocardiography correlates with ventricular dyssynchrony assessed by tissue Doppler imaging in patients with reduced ventricular ejection fraction

Objectives

The relationships between filtered QRS duration and ventricular dyssynchrony were studied.

Methods

We measured filtered QRS duration on signal-averaged electrocardiography and analyzed tissue Doppler imaging in chronic heart failure patients with ejection fraction less than 50%.

Results

In 64 patients, interventricular and intraventricular dyssynchronies were observed in 25 and 38 patients, respectively. All patients with interventricular dyssynchrony were associated with intraventricular dyssynchrony. Filtered QRS showed 0.82 and 0.78 of the area under the curve (AUC) in the receiver operating characteristic curve (ROC) for the detection of interventricular and intraventricular dyssynchrony, respectively, with 89.7% and 96.2% specificity and 52.0% and 52.6% sensitivity, with cutoff values of 174 and 153 milliseconds. Specificity and sensitivity as well as AUC were lower in the ROC of QRS duration than filtered QRS duration.

Conclusion

Filtered QRS duration provided more reliable information to estimate ventricular dyssynchrony in patients with reduced ventricular ejection fraction than QRS duration did.     

Relationship between QRS duration and left ventricular dyssynchrony in patients with end-stage heart failure

INTRODUCTION: Patients with end-stage heart failure and a wide QRS complex are considered candidates for cardiac resynchronization therapy (CRT). However, 20% to 30% of patients do not respond to CRT. Lack of left ventricular dyssynchrony may explain the nonresponse. Accordingly, we evaluated the presence of left ventricular dyssynchrony using tissue Doppler imaging (TDI) in 90 consecutive patients with heart failure. METHODS AND RESULTS: Ninety patients with severe heart failure (left ventricular ejection fraction <35%, New York Heart Association class III-IV) were prospectively evaluated. Based on QRS duration, 30 consecutive patients with a narrow QRS complex were included (QRS duration 150 ms). All patients underwent TDI to assess left ventricular dyssynchrony. Extensive left ventricular dyssynchrony was defined as an electromechanical delay on TDI between the septum and lateral wall, the so-called septal-to-lateral delay, of >60 ms. Severe dyssynchrony was observed in 27% of patients with narrow QRS complex, 60% with intermediate QRS duration, and 70% with wide QRS complex. No relation existed between QRS duration and septal-to-lateral delay. CONCLUSION: From 30% to 40% of heart failure patients with QRS duration >120 ms do not exhibit left ventricular dyssynchrony, which may explain the nonresponse to CRT. Alternatively, 27% of patients with heart failure and a narrow QRS complex show significant left ventricular dyssynchrony and may be candidates for CRT.     

Prevalence of left ventricular dyssynchrony in patients with heart failure assessed by a novelprogrammer-cardioGRAF

Objectives Left ventricular systolic dyssynchrony is the most important determinant of response to cardiac resynchronization therapy （CRT）, playing a vital role to predict improvement of systolic function or LV reverse remodeling. CardioGRAF is a novel programmer based on the ECG gated single photon emission computed tomography （G-SPECT） imaging to detect LV systolic and diastolic dyssynchrony simultaneously. This study was to investigate the prevalence of systolic and diastolic left ventricular （LV） dyssynchrony in patients with heart failure. Methods We retrospectively studied 69 patients with heart disease, including 31 patients who had symptoms of heart failure （NYHA class Ⅱ-Ⅲ）, and 38 patients who had no symptoms of heart failure. （NYHA class Ⅰ）. G- SPECT data were analyzed by cardiaGRAF, and measurements included the time to end systole （TES）, the time to peak ejection （TPE）, the time to peak filling （TPF）, TES＋TPF and maximal difference （MD） of each parameters were obtained, using the 95th percentile of the control group as a cutoffof 150 ms for MD-TES, 139 ms for MD-TPE, 345 ms for MD-TPF and 315 ms for MD-TES＋TPF. Results The prevalence of LV systolic dyssynchrony was significantly higher in heart failure patients with reduced LV ejection fraction （LVEF）〈45% （72% for MD-TES; 64% for MD-TPE） compared with heart failure patients with preserved LVEF=45% （14% for both MD-TES and MD-TPE; P=0.002, P=0.005, respectively）; The prevalence of MD-TES〈150 ms was higher in NYHA class Ⅲ patients （64%） compared with NYHA class Ilpatients （27%, P=0.049）. However, the prevalence of the LV diastolic dyssynchrony were high but not difference between NYHA class III（47% for both MD-TPF and MD-TES＋TPF） and class Ⅲ（63% for MD-TPF; 69% for MD-TES＋TPF; P=NS） patients as well as between patients with preserved LVEF （43% for both MD-TPF and MD-TES＋TPF） and patients with reduced LVEF（64% for MD-TPF; 72% for MD-TES＋TPF; P=NS）. Conclusions The prevalence of LV systolic dyssynchrony was high in heart failure patients with reduced LVEF. Diastolic dyssynchrony was common in patients with heart failure. CardioGRAF maybe a useful method to detect LV dyssynchrony （J Gerlatr Cardio12009; 6：151-156）.     

Concordance Between Mechanical and Electrical Dyssynchrony in Heart Failure Patients: A Function of the Underlying Cardiomyopathy?

Background: Cardiac resynchronization therapy (CRT) improves heart failure (HF) symptoms through a reduction of cardiac mechanical dyssynchrony. Mechanical dyssynchrony is currently estimated by electrical dyssynchrony (QRS duration). It is known that electrical and mechanical dyssynchrony are not well correlated in HF patients. However, there is limited information about whether this relationship might be influenced by the underlying cardiomyopathy.
Methods: Doppler echocardiography was performed in 88 patients presenting with heart failure due to ischemic (n = 42) or nonischemic (n = 46) heart disease, left ventricular ejection fraction <40%, New York Heart Association class II–IV, regardless of their QRS duration. Interventricular dyssynchrony was assessed by the time interval between preaortic and prepulmonary ejection times. Intraventricular dyssynchrony was ascertained by (1) the delay between the earliest and the latest peak negative longitudinal strain recorded in the basal and mid-segments of the lateral and septal walls (TMinMax) and (2) the standard deviation of time-to-peak in the same segments (SDdys).
Results: The correlation coefficient between QRS duration and mechanical interventricular dyssynchrony was r = 0.47 (P < 0.001) in patients with nonischemic disease and nonsignificant in patients with ischemic disease. Similarly, the correlation coefficient between QRS duration and mechanical intraventricular dyssynchrony was significant in patients with nonischemic disease (r = 0.37, P = 0.01 for TMinMax; r = 0.42, P = 0.003 for SDdys) and nonsignificant in patients with ischemic disease.
Conclusion: The concordance between electrical dyssynchrony assessed by QRS duration and mechanical dyssynchrony assessed by myocardial strain is dependent upon the underlying cardiomyopathy. This observation may improve our understanding of the various responses observed in CRT patients.     

Has Mechanical Dyssynchrony Still a Role in Predicting Cardiac Resynchronization Therapy Response?

Current guidelines for cardiac resynchronization therapy (CRT) include electrical but not mechanical dyssynchrony assessment. Our study aims to investigate the effects of isolated or combined mechanical and electrical dyssynchrony, according, respectively, to a standard deviation of tissue Doppler imaging (TDI) derived time to systolic peak ≥32.6 ms and to a QRS duration ≥120 ms, in predicting CRT reverse remodeling. Method: One hundred ninety‐two CRT patients were studied. All patients underwent a complete standard and TDI echocardiography examination before and 6 months after CRT. According to baseline evaluation patients were divided into Group 1, patients with isolated electrical dyssynchrony (QRS ≥ 120 ms, TS‐SD < 32.6), Group 2, patients with isolated mechanical dyssynchrony (QRS < 120 ms, TS‐SD ≥ 32.6) and Group 3, patients with combined electrical and mechanical dyssynchrony (QRS ≥ 120 ms, TS‐SD ≥ 32.6). Patients were considered CRT responders according to ≥15 left ventricular end‐systolic volume (LVESV) reduction at follow‐up (FU). Result: At FU, 86 (45%) patients were responders. The highest CRT response rate was observed in Group 3 (62/119, 52%, P < 0.001 vs. Group 1). No significant differences in response rate were observed between Group 1 (13/47, 27%) and Group 2 (11/26, 42%). In Group1, CRT did not induce any significant change in LV end‐diastolic volume (LVEDV), LVESV, LV ejection fraction (LVEF), myocardial performance index (MPI), while in Group 2, LVEF (P < 0.001) and MPI (P < 0.05) were improved. In Group 3, LVEDV, LVESV, LVEF, MPI were significantly improved (P < 0.0001 for all). Conclusion: Our data demonstrate that the highest CRT response rate can be achieved by combining traditional QRS criterion and a currently used echocardiographic dyssynchrony parameter. (Echocardiography, 2010;27:831‐838)     

Three-dimensional echocardiographic evaluation of mechanical dyssynchrony in systolic heart failure with narrow QRS complex

ObjectivesTo investigate the role of three-dimensional echocardiography (3DE) in evaluation of left ventricular mechanical dyssynchrony (LVMD) in heart failure (HF) patients with narrow QRS.Methods143 subjects (70 with HF and narrow QRS, 23 with HF and LBBB and 50 controls) were subjected to 3DE, evaluating global and regional dyssynchrony using systolic dyssynchrony index, maximum segmental dyssynchrony and opposite segment dyssynchrony. Spatial distribution of LVMD was studied in each patient using 3DE derived regional time volume curves. Extent of LVMD in HF patients with narrow QRS was compared to those with left bundle branch block (LBBB).ResultsFrequency of LVMD was similar in HF patients with narrow QRS or LBBB (55.7% vs. 47.8%, p = NS). There was no difference in the severity of LVMD between these two groups (10.7 ± 6.7% vs. 12.1 ± 7.4%, p = NS). Both HF groups had significantly more dyssynchrony than controls. A scattered pattern of distribution of asynchronous segments was seen in narrow QRS patients; 33.96% of them had their earliest contracting segment, instead of delayed segment, located in areas conventionally targeted for LV pacing i.e. anterolateral, inferolateral or inferior segments.Conclusions3DE confirmed significant dyssynchrony in  > 50% HF patients with narrow QRS as demonstrated by other imaging methods. 3D distribution patterns of asynchronous segments indicate possibility of left ventricular mechanics related reasons responsible for lack of CRT responsiveness, an observation that generates hypothesis on possible reasons of CRT non-responsiveness.     

Prevalence of dyssynchrony derived from echocardiographic criteria in heart failure patients with normal or prolonged QRS duration

Cardiac resynchronization therapy (CRT) for heart failure is targeted at specific patients with mechanical dyssynchrony. We aimed to evaluate the prevalence of dyssynchrony in heart failure patients with either normal or prolonged QRS duration using Doppler imaging. Sixty heart failure patients with idiopathic dilated cardiomyopathy (30 with prolonged QRS duration 30 with normal QRS duration) underwent standard echocardiography and tissue Doppler imaging examinations. Difference between left and right ventricular pre-ejection intervals of more than 40 msec was considered a marker of interventricular dyssynchrony. Intraventricular dyssynchrony was defined as a delay of 60 msec between the time to peak velocities of the septum and left ventricular lateral wall. Patients who have either intra- or interventricular dyssynchrony were defined as with cardiac dyssynchrony. Dyssynchrony was observed in 7 (23.3%) heart failure patients with normal QRS duration versus 26 (86.7%) patients with prolonged QRS duration. There was significant difference between the prevalence of dyssynchrony derived from echo criteria in two groups (P<0.05). Although patients with prolonged QRS duration have a high prevalence of dyssynchrony, yet some still have good cardiac synchronicity. Moreover, dyssynchrony also exists in a small percentage of heart failure patients with normal QRS duration. To identify the potential responders for CRT, both QRS duration and cardiac synchronicity should be assessed.     

Mechanical dyssynchrony and deformation imaging in patients with functional mitral regurgitation

Chronic functional mitral regurgitation(FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy(DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle(LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy(CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.