Association between myocardial mechanical dispersion and ventricular arrhythmogenicity in chagas cardiomyopathy

Chagas disease is a major health concern in Latin America. Ventricular arrhythmia (VA) is a hallmark of Chagas cardiomyopathy (CCM), associated with worse prognosis. The present study aimed to verify the association between myocardial mechanical dispersion (MD) and ventricular arrhythmogenicity in CCM. In a cross-sectional study, 77 patients (55.8?±?10.4 years) with CCM were evaluated. Global longitudinal strain (GLS) and MD were assessed by echocardiography, derived from the speckle tracking technique. Myocardial MD was measured from the onset of the Q/R wave on electrocardiogram to the peak longitudinal strain in 16 segments of the left ventricle. Frequency and complexity of ventricular extrasystoles (VES) were assessed by dynamic electrocardiography. The density and complexity of VES and the presence of non-sustained ventricular tachycardias (NSVTs) increase as MD increases. In logistic regression, MD was the only variable associated with the presence of paired VES and ventricular bigeminy. In addition, both MD and GLS were associated with the presence of NSVT (both, p?<?0.01), and MD was independently associated with NSVT (OR 1.04, 95% CI 1.004–1.201, p?=?0.031). In CCM, MD is associated with a higher density and complexity of VES, including NSVT.

     

卡维地洛对扩张型心肌病QT间期离散度及室性心律失常变化的影响

目的 :探讨卡维地洛治疗对扩张型心肌病 (DCM )患者心电图QT间期离散度 (QTd)及室性心律失常的影响。方法 :80例DCM患者分为基础治疗组 (A组 ,40例 )及基础治疗加卡维地洛治疗组 (B组 ,40例 ) ,B组在基础治疗上加服卡维地洛 10mg ,2次 /d ,疗程 9个月。治疗前后应用 2 4h动态心电图和多普勒超声心动图 ,观测QTd、QTcd、HR、室性心律失常 (VA )如室性早搏 (PVC)、非持续性室性心动过速 (NSVT) )的发生情况、左心室射血分数(LVEF)。结果 :B组QTd、QTcd及室性心律失常 (VA )发生率均较A组显著降低 (P均 <0 0 1) ,左室射血分数(LVEF)较A组明显提高 (P <0 0 1) ,而HR、血压无明显变化 (P >0 0 5 )。提示B组疗效优于A组。结论 :DCM患者长期应用卡维地洛可显著降低QTd、QTcd及VA的发生率 ,改善心功能 ,改善预后     

An impaired renal function: a predictor of ventricular arrhythmias and mortality in patients with nonischemic cardiomyopathy and heart failure

Background: This study investigated the overall mortality and the incidence of ventricular tachyarrhythmia (VT) in 99 patients with nonischemic cardiomyopathy (NICM) and with an implantable cardioverter defibrillator (ICD) suffering from heart failure. Methods: We performed a stepwise regression model to identify independent risk factors for the occurrence of ventricular arrhythmias. Using a Cox regression model, independent risk factors for total mortality were evaluated and, subsequently, a Kaplan‐Meier analysis was applied. The primary endpoint of this study was the identification of independent predictors of overall mortality and the incidence of malignant arrhythmias. Results: One hundred twenty‐five VT (≥310 ms), 51 fast VT (between 310 ms and 240 ms), and 48 episodes of ventricular fibrillation (≤240 ms) were documented in 32 patients. Independent predictors of arrhythmias detected and treated by the ICD included female gender (odds ratio [OR] 3.4), lack of statin therapy (OR 3.5), and increased serum creatinine (OR 3.7). The Kaplan‐Meier analysis showed no difference in survival between participants with or without VT. Total mortality was predicted by increased age (OR 2.3) and an impaired renal function (OR 1.9), independently. Conclusions: In this cohort of NICM patients with heart failure, female gender, lack of statin therapy, and increased creatinine represented independent risk factors for the incidence of malignant arrhythmias. Furthermore, renal insufficiency and age favored total mortality. Considering these results, impaired renal function might represent a valuable noninvasive tool to identify NICM patients who, despite ICD implantation, have the highest risk of mortality and therefore require a particularly thorough follow‐up. (PACE 2011; 34:894–899)     

Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy

Objective: We assessed the value of speckle tracking two-dimensional (2D) strain echocardiography (2DSE) measured mechanical dispersion (MD) with other imaging and electrocardiographic parameters in differentiating hypertrophic cardiomyopathy (HCM) patients with and without nonsustained ventricular tachycardia (NSVT) on 24-h ambulatory ECG monitoring.

Methods and results: We studied 31 patients with HCM caused by the Finnish founder mutation MYBPC3-Q1061X and 20 control subjects with comprehensive 2DSE echocardiography and cardiac magnetic resonance imaging (CMRI). The presence of NSVT was assessed from ambulatory 24-h ECG monitoring.

NSVT episodes were recorded in 11 (35%) patients with HCM. MD was significantly higher in HCM patients with NSVT (93?±?41?ms) compared to HCM patients without NSVT (50?±?18?ms, p?=?0.012) and control subjects (41?±?16?ms, p?Conclusions: Increased mechanical dispersion was associated with NSVT in HCM patients on 24-h ambulatory ECG monitoring.

• Key messages

• The prediction of sudden cardiac death in hypertrophic cardiomyopathy remains a challenge and novel imaging methods are required to identify individuals at risk of malignant ventricular arrhythmias.

• Mechanical dispersion by speckle tracking echocardiography is associated with NSVT on 24-h ambulatory ECG monitoring in patients with hypertrophic cardiomyopathy

     

Late gadolinium enhancement CMR in patients with tachycardia-induced cardiomyopathy caused by idiopathic ventricular arrhythmias

Background: Idiopathic ventricular arrhythmias in the form of monomorphic premature ventricular contractions (PVC) and/or ventricular tachycardia (VT) can cause tachycardia‐induced cardiomyopathy (TICMP). The aim of this study was to determine the prevalence of late gadolinium enhancement (LGE) in patients with TICMP caused by idiopathic ventricular arrhythmias. Methods: The study population consisted of 298 consecutive patients (174 F/124 M; mean age 45 ± 17 years) with frequent PVCs and/or VT. TICMP was defined as left ventricular ejection fraction (LVEF) of ≤50% in the absence of any detectable underlying heart disease and improvement of LVEF ≥15% after effective treatment of index ventricular arrhythmia. Results: Twenty‐seven (9.1%) patients found to have LVEF ≤50% and diagnosed as presumptive TICMP. Improvement in LVEF after effective treatment of index ventricular arrhythmia was observed in 22 of 27 patients (TICMP group; mean PVC burden of 30.8 ± 9.9%). LVEF did not improve in five of 27 patients (primary cardiomyopathy group; mean PVC burden of 28.8 ± 10.1%). LGE‐cardiac magnetic resonance (CMR) imaging was performed in 19 of 22 patients with TICMP and one patient (5%) had LGE. All five patients with primary cardiomyopathy underwent LGE‐CMR imaging and four patients (80%) had LGE. Conclusions: LGE is a rare finding in patients with TICMP caused by idiopathic ventricular arrhythmias. LGE‐CMR can be used in the diagnostic work‐up of patients with TICMP. Further prospective studies are required to determine the role of LGE‐CMR in predicting the recovery of left ventricular systolic dysfunction in patients with presumptive TICMP. PACE 2012; 35:465–470)     

Characterization of the electroanatomic substrate for monomorphic ventricular tachycardia in patients with nonischemic cardiomyopathy

Ventricular arrhythmias are common in the setting of nonischemic cardiomyopathy. The etiology for the cardiomyopathy is frequently not identified and the label of "idiopathic" is applied. Interstitial fibrosis with conduction system involvement and associated left bundle branch block characterizes the disease process in some patients and the mechanism for monomorphic ventricular tachycardia is commonly bundle branch reentry. However, most patients with nonischemic cardiomyopathy have VT due to myocardial reentry and demonstrate marked myocardial fibrosis and electrogram abnormalities. Although patient specific, the overall distribution of electroanatomic abnormalities appears to be equal on the endocardium and epicardium. The extent of electrogram abnormalities appears to parallel arrhythmia presentation and/or inducibility. Patients with sustained uniform morphology VT have the most extensive endocardial and epicardial electrogram abnormalities. Magnetic electroanatomic voltage mapping provides a powerful tool to characterize the location and extent of the arrhythmia substrate. Basal left ventricular myocardial involvement, as indexed by the location of contiguous electrogram abnormalities, is common in patients with sustained VT and left ventricular cardiomyopathy. The relatively equal distribution of electrogram abnormalities on the endocardium and epicardium, and the results of mapping and ablation attempts, suggest that critical parts of the reentrant circuit may be epicardial. Unique features of the electroanatomic substrate associated with cardiomyopathy due to Chagas' disease, sarcoidosis, and arrhythmogenic right ventricular dysplasia are also discussed.     

Biventricular myocardial strain analysis in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) using cardiovascular magnetic resonance feature tracking

Background

Fibrofatty degeneration of myocardium in ARVC is associated with wall motion abnormalities. The aim of this study was to examine whether Cardiovascular Magnetic Resonance (CMR) based strain analysis using feature tracking (FT) can serve as a quantifiable measure to confirm global and regional ventricular dysfunction in ARVC patients and support the early detection of ARVC.

Methods

We enrolled 20 patients with ARVC, 30 with borderline ARVC and 22 subjects with a positive family history but no clinical signs of a manifest ARVC. 10 healthy volunteers (HV) served as controls. 15 ARVC patients received genotyping for Plakophilin-2 mutation (PKP-2), of which 7 were found to be positive. Cine MR datasets of all subjects were assessed for myocardial strain using FT (TomTec Diogenes Software). Global strain and strain rate in radial, circumferential and longitudinal mode were assessed for the right and left ventricle. In addition strain analysis at a segmental level was performed for the right ventricular free wall.

Results

RV global longitudinal strain rates in ARVC (−0.68 ± 0.36 sec⁻¹) and borderline ARVC (−0.85 ± 0.36 sec⁻¹) were significantly reduced in comparison with HV (−1.38 ± 0.52 sec⁻¹, p ≤ 0.05). Furthermore, in ARVC patients RV global circumferential strain and strain rates at the basal level were significantly reduced compared with HV (strain: −5.1 ± 2.7 vs. -9.2 ± 3.6%; strain rate: −0.31 ± 0.13 sec⁻¹ vs. -0.61 ± 0.21 sec⁻¹). Even for patients with ARVC or borderline ARVC and normal RV ejection fraction (n=30) global longitudinal strain rate proved to be significantly reduced compared with HV (−0.9 ± 0.3 vs. -1.4 ± 0.5 sec⁻¹; p < 0.005). In ARVC patients with PKP-2 mutation there was a clear trend towards a more pronounced impairment in RV global longitudinal strain rate. On ROC analysis RV global longitudinal strain rate and circumferential strain rate at the basal level proved to be the best discriminators between ARVC patients and HV (AUC: 0.9 and 0.92, respectively).

Conclusion

CMR based strain analysis using FT is an objective and useful measure for quantification of wall motion abnormalities in ARVC. It allows differentiation between manifest or borderline ARVC and HV, even if ejection fraction is still normal.     

Effect of alcohol septal ablation in patients with hypertrophic cardiomyopathy on left-ventricular mechanical dyssynchrony as assessed by phase analysis of gated SPECT myocardial perfusion imaging

Patients with hypertrophic cardiomyopathy (HCM) may have delayed septal activation and left ventricular (LV) mechanical dyssynchrony, and may improve after alcohol septal ablation (ASA). This study used phase analysis of gated SPECT myocardial perfusion imaging (MPI) to evaluate septal activation and LV dyssynchrony in HCM patients pre- and post-ASA. Phase analysis was applied to 28 controls, and 32 HCM patients having rest MPI pre- and post-ASA to assess septal-lateral mechanical activation delay (SLD) and consequent LV dyssynchrony. In addition, phase analysis was applied to another group of 30 patients having serial MPI to measure variability of the LV dyssynchrony parameters on serial studies. ASA significantly reduced SLD and improved LV synchrony in the HCM patients with SLD?相似文献   

Factors affecting onset of ventricular arrhythmias and sudden death in patients with dilated cardiomyopathy

The study of 46 patients suffering from dilated cardiomyopathy has shown that both ventricular tachycardias detected at 24-h ECG monitoring and late ventricular potentials are essential predictors of sudden arrhythmic death. These predictors depend neither on severity of left ventricular systolic and diastolic dysfunction nor on severity of cardiac decompensation.     

Association between high-sensitivity C-reactive protein and left ventricular diastolic function assessed by echocardiography in patients with cardiovascular risk factors

High-sensitivity C-reactive protein (hsCRP) has been demonstrated to play a causal role in atherosclerosis and to predict cardiovascular events in the general population. On the other hand, left ventricular (LV) hypertrophy and diastolic dysfunction assessed by echocardiography can also predict cardiovascular events in patients with cardiovascular risk factors. However, there are few data regarding the relationships among hsCRP, LV hypertrophy, and diastolic function. We examined the relationships among hsCRP, LV hypertrophy, and diastolic function in 185 patients (65±11 years), who had no overt heart disease, but had cardiovascular risk factors, including hypertension, diabetes, and dyslipidemia. Echocardiography was performed to measure the left ventricular mass index (LVMI) as a parameter of LV hypertrophy. LV diastolic function was assessed by the ratio (E/A) of early (E) and late (A) diastolic transmitral flows, early diastolic mitral annular velocity (E'), and the ratio (E/E') of E to E' using Doppler echocardiography. The hsCRP was correlated with LVMI (r=0.228, p=0.002), E' (r=-0.276, p<0.001), and E/E' (r=0.419, p<0.001). The E/E' as a parameter of LV diastolic function showed the closest correlation to hsCRP. These results indicate that elevated hsCRP reflects LV diastolic dysfunction rather than LV hypertrophy. We therefore suggest that hsCRP may be a marker of subclinical LV diastolic dysfunction in patients with cardiovascular risk factors.     

Assessment of myocardial fibrosis by endoventricular electromechanical mapping in experimental nonischemic cardiomyopathy

Cardiac fibrosis plays an important prognostic role in nonischemic cardiomyopathy (NICM), making it a potential therapeutic target. Although electromechanical mapping has been used to identify myocardial scar and facilitate intramyocardial intervention in the setting of ischemic heart disease, its application has not been described in NICM. We assessed the detection of myocardial fibrosis by endoventricular electromechanical mapping in an experimental model of NICM. The NOGA^® XP system was used to perform left ventricular mapping in twelve sheep that had undergone intracoronary doxorubicin dosing to induce NICM and in six healthy control animals. Results for endocardial voltage and mechanical shortening were evaluated against myocardial fibrosis burden, as determined by delayed-enhancement cardiac magnetic resonance and quantitative histomorphometry. Doxorubicin treatment resulted in dilated cardiomyopathy with moderate-severe impairment of left ventricular ejection fraction. Late gadolinium uptake was present in 9/12 doxorubicin animals, while histological fibrosis was approximately doubled compared to controls and was distributed multisegmentally throughout the left ventricle. Cardiomyopathy was associated with widespread reductions in unipolar and bipolar voltage amplitude and endocardial shortening. Each parameter showed an inverse relationship with the burden of fibrosis. Moreover, unipolar voltage and linear local shortening ratio displayed moderate accuracy for identifying myocardial segments with delayed contrast enhancement or increased fibrosis content, with optimal discriminatory thresholds of 7.5 mV and 11.5%, respectively. In this model of NICM, electromechanical mapping shows potential for delineating segmental differences in fibrosis. Pending clinical evaluation, it may therefore have applicability for directing targeted intramyocardial interventions in nonischemic heart disease.     

Monomorphic ventricular tachycardia induced by cardiac resynchronization therapy in patient with severe nonischemic dilated cardiomyopathy

We report the case of a patient with severe nonischemic dilated cardiomyopathy in whom cardiac resynchronization therapy (CRT) was the source of incessant, drug-resistant, monomorphic ventricular tachycardia (VT). VT recurrences were only resolutive with inactivation of CRT and reactivation of CRT reproduced VT occurrence. The possible pathophysiology of the VT and the potential ventricular proarrhythmic risk related to CRT are discussed. This report points out clearly that CRT can induce ventricular arrhythmias and suggests the need for CRT systematically associated with a defibrillation system.     

应用超声二维应变成像技术评估肥厚型心肌病患者左心室心肌收缩的不同步性

目的 应用超声二维应变成像技术评估肥厚型心肌病(HCM)患者左心室心肌收缩的不同步性.方法 21例肥厚型心肌病患者、21例高血压病患者及21例正常人,分别记录并存储二尖瓣环、乳头肌及心尖部水平左心室短轴二维图像;获取其径向应变和圆周应变曲线.分别测量每个节段从心电图R波到峰值径向应变之间的时间(Trs)和从心电图R波到峰值圆周应变之间的时间(Tcs);并且分别计算每个患者18个节段Trs的标准差(Trs-18SD)和18个节段Tcs的标准差(Tcs-18SD).将HCM组患者所有心肌节段分为肥厚节段与非肥厚节段心肌,比较两组间Trs和Tcs的差异.结果 HCM组患者Trs-18SD明显高于HHD组患者及正常对照组[HCM组: (83±18)ms, HHD组: (52±15)ms, 对照组: (46±9)ms, P<0.001],而高血压组与正常对照组之间无明显差异.HCM组患者Tcs-18SD明显高于HHD组患者及正常对照组[HCM组:(84±18)ms, HHD组:(48±10)ms,对照组:(46±10)ms,P<0.001],而高血压组与正常对照组之间无明显差异.肥厚节段心肌Trs明显低于非肥厚节段心肌(341±42 vs 388±40,P<0.05);而肥厚节段心肌Tcs虽然低于非肥厚节段心肌,但其差异无统计学意义.结论 肥厚型心肌病患者左心室收缩存在不同步性,超声二维应变成像技术为评估左心室收缩不同步性提供了无创性新方法.     

超声应变显像技术评价肥厚性心肌病局部心肌功能的探讨

目的探讨超声组织应变显像(SI)技术评估肥厚性心肌病(HCM)患者局部心肌收缩与舒张功能的价值.方法 HCM患者30例,25例正常人为对照组.选取标准的心尖四腔切面,在心动周期中分别测量室间隔与左室侧壁基底段、中间段、心尖段沿心脏长轴方向上的收缩期峰值应变(εet),观察HCM组出现的收缩期反向应变节段;统计两组室间隔中段和后壁中段的收缩后应变(PSS)节段数并计算其幅度值;将室间隔中段的应变值与室壁厚度进行相关分析.结果①正常组各节段εet从心底至心尖呈逐渐减低趋势,但节段间差异无显著性意义(P＞0.05);②HCM组与正常组εet比较,HCM组各节段应变均显著降低(P＜0.05);③HCM组内室间隔中段应变最低,与基底段、心尖段比较差异有显著性意义(P＜0.05),本组病例大约40%的肥厚节段收缩期可见反向应变;④病变组和正常组均存在PSS,然而与病变组比较正常组PSS节段少、幅度低(P＜0.05);⑤HCM组和正常组室间隔中段的εet与室壁厚度密切相关(r＝0.83).结论 HCM患者无论肥厚节段或非肥厚节段均存在收缩舒张功能减低,且以肥厚节段病损更重,应变显像技术能对其进行准确评价.     

急性心肌梗死患者室性心律失常的发生与肿瘤坏死因子-α仪表达水平的相关性分析

目的 研究急性心肌梗死患者的肿瘤坏死因子-α(TNF-α)水平与心肌梗死后室性心律失常发生之间的关系.方法 确诊急性心肌梗死患者65例,在不同时间点检测其心肌酶谱(cTnI、CK、CK-MB、AST、LDH)及TNF-α表达水平,并监测其心律失常情况,进行相关性分析.结果 血浆TNF-α水平与心肌酶谱表达呈正相关(P＜0.05),TNF-α仪表达与心肌梗死后室性期前收缩Lown分级呈正相关(P＜0.05),急性前壁心肌梗死患者TNF-α水平较其他部位梗死患者高(均P＜0.05).结论 急性心肌梗死后TNF-α表达水平与室性心律失常存在一定关系,心肌梗死后室性心律失常发生多的患者其TNF-α表达水平高.     

磁共振特征性追踪技术对肥厚型心肌病心肌应变的初步研究

目的采用心脏磁共振特征性追踪(cardiovascular magnetic resonance feature tracking,CMR-FT)技术对肥厚型心肌病患者的心功能及心肌节段应变进行分析,探讨CMR-FT对肥厚性心肌病患者早期运动异常检测的可行性。材料与方法对17例肥厚型心肌病患者及14名健康志愿者进行3.0 T SSFP电影序列扫描,使用CVI软件检测心功能,并对48个肥厚的心肌节段及健康志愿者中42个正常心肌节段进行特征性追踪(feature tracking,FT)后处理。结果肥厚型心肌病患者与健康志愿者左心功能参数(左心室舒张末期容积、左心室收缩末期容积及左心室射血分数)的差异无统计学意义(P均0.05),肥厚的心肌节段的圆周应变、长轴应变及峰值收缩期圆周应变、峰值收缩期长轴应变均低于正常的心肌节段[(-5.26±2.70)%vs(-11.68±2.06)%,(-7.92±5.07)%vs(-13.93±3.89)%,(-10.44±5.46)%vs(-18.43±2.99)%,(-12.29±8.17)%vs(-20.26±2.93)%,P均0.05]。结论对于心功能正常的肥厚性心肌病患者,CMR-FT技术能够早期检测出肥厚患者肥厚心肌节段应变的变化,提示心肌应变量的改变能够比左心室功能参数更早地发现心肌收缩功能异常。     

心肌应变率成像评价肥厚型心肌病左心室局部舒张功能的应用研究

目的应用应变率成像（SRI）技术评价肥厚型心肌病（HCM）左心室局部舒张功能。方法分别获得30例HCM患者和30例正常对照者心尖四腔及长轴观图像，在应变率模式下测量各室壁基底段、中间段及心尖段舒张早期应变率（SRe）、舒张晚期应变率（SRA）和SRE/SRA等参数。结果与正常对照组相比，HCM组舒张早期负向应变率（SRE-）的节段数明显增多，差异有统计学意义（P〈0．01），并且室间隔各节段s艮绝对值显著增大；HCM组SRE降低，SRA增高或无明显变化，SRE/SRA明显减小，部分节段SRE/SRA〈1。结论SRI可以无创、准确地描述局部心肌组织的形变特性，检测局部舒张功能的异常，为临床评定HCM局部心肌舒张功能提供准确、敏感的量化指标。     

维持性血液透析患者QT间期离散度与室性心律失常的关系及其影响因素

目的 检测60例尿毒症行维持性血液透析(MHD)患者透析前后QT间期离散度(QTd)的变化,初步探讨MHD患者QTd与室性心律失常的关系及其影响因素.方法 选择南方医科大学第三附属医院血液净化中心60例MHD患者分别于透析前及透析后记录12导联同步心电图,计算QTd值,并进行临床及相关实验室检查,进行统计学分析.结果 存在室性心律失常的MHD患透析前QTd高于无室性心律失常患者(50.84±13.56比39.57±14.72,P＜0.01);透析后QTd较透析前明显增大(59.73±20.11比44.23 ±13.26,P＜0.01);回归分析表明,透析后QTd的增幅与K +浓度的变化及HCO3-的变化幅度呈正相关 (分别为r=0.67,P＜0.01;r=0.79,P＜0.01).结论 MHD患者QTd与室性心律失常的发生有关;透析后QTd进一步增大;QTd增大的机制与K +浓度的快速变化及酸中毒的快速纠正有关.