The utility of fragmented QRS complexes to predict significant intraventricular dyssynchrony in nonischemic dilated cardiomyopathy patients with a narrow QRS interval

BACKGROUND:

Fragmented QRS complexes in the electrocardiograms (ECGs) of patients with coronary artery disease are associated with adverse cardiac events. However, there are limited data on its predictive usefulness in patients with nonischemic dilated cardiomyopathy. Left ventricular dyssynchrony is common in heart failure patients who have wide QRS intervals, but its frequency in patients with narrow QRS intervals is uncertain.

OBJECTIVES:

To investigate the relationship between fragmented QRS complexes and intraventricular dyssynchrony in patients with nonischemic dilated cardiomyopathy in sinus rhythm.

METHODS:

Sixty nonischemic dilated cardiomyopathy patients with sinus rhythm and narrow QRS intervals were recruited. Forty patients had a fragmented QRS in their basal ECG, and 20 patients did not have a fragmented QRS. Patients were analyzed for correlation between fragmented QRS complexes and intraventricular dyssynchrony.

RESULTS:

The maximal difference in time to the peak myocardial systolic velocity between any two left ventricular segments (Max-ASE Sys), and maximal difference between Max-ASE Sys and the mean value of all segments (Max-ASE to Mean Sys) were significantly higher in patients with fragmented QRS complexes (P=0.001 and P=0.003, respectively). Seventy-two per cent of the patients with fragmented QRS complexes had significant left ventricular dyssynchrony; 15% of patients without fragmented QRS complexes had significant left ventricular dyssynchrony (P<0.0001). The presence of fragmented QRS complexes in leads corresponding to the specific ventricular segment in basal ECG was found to detect intraventricular dyssynchrony with 90.6% sensitivity (negative predictive value of 85%).

CONCLUSION:

Fragmentation in the resting ECG is associated with significant intraventricular dyssynchrony in patients with nonischemic cardiomyopathy, narrow QRS and sinus rhythm. Fragmentation in ECG might be useful in identifying patients who could benefit from cardiac resynchronization therapy.     

Optimizing lead placement for pacing in dyssynchronous heart failure: The patient in the lead

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实时三维超声心动图评价左室不同步性及其与收缩功能的关系研究

目的探讨实时三维超声心动图评价左室不同步性及其与左室收缩功能关系的应用价值。方法对14例正常人和20例临床诊断为扩张型心肌病（扩心）患者实时三维超声心动图时间-容积曲线进行比较分析。结果14例正常人与20例扩心患者16节段、12节段（中间段和基底段）和6节段（基底段）最小收缩容积点时间的标准差和最大差值均有显著性差异,P均〈0.0001。正常人平均收缩期不同步化指数为（1.4±0.7）%,扩心患者为（13.1±3.8）%。扩心患者收缩期不同步化指数与左室收缩功能有良好的相关性,与左室射血分数相关系数r为-0.75,P〈0.0001,与QRS间期不相关。结论实时三维超声心动图是一种可行的、具有可重复性的评价左室不同步性和收缩功能的方法。     

慢性充血性心力衰竭患者左室运动不同步与右室收缩功能减低的相关性研究

目的探讨慢性充血性心力衰竭(心衰)患者左室运动不同步与右室收缩功能减低之间有无相关性。方法 72例心衰患者行二维应变及常规超声检查。测量前间隔与后壁收缩期轴向应变达峰时间差(SPWMD),以SPWMD≥130ms为左室不同步的标准,测量收缩期三尖瓣环位移(TAPSE)等参数。并以TAPSE≤14mm为截值分为右室收缩功能正常组与减低组。结果 22例(30.56%)患者存在右室收缩功能减低,46例(63.90%)患者存在左室内运动不同步。右室收缩功能正常组与减低组间的SPWMD无明显差异(P=0.658),TAPSE与SPWMD之间无明显相关(r=0.136,P=0.255)。结论心衰患者的右室功能减低与左室内机械运动不同步无明显相关。全面评价心功能需要同时定量分析左、右室功能。     

组织速度显像对QRS波＜120ms心衰患者左心室收缩不同步的评价

目的:应用组织速度显像(TVI)技术评价QRS波＜120ms心衰患者的左心室收缩同步性.方法:本研究共收入18例正常人(对照组)和EF≤45%(Simpson法测定)且QRS波＜120ms的心衰患者(CHF组)20例.利用TVI获取左心室心尖切面心肌各节段多普勒组织速度曲线,测量收缩达峰时间(Ts),计算12节段TS的标准差(Ts-SD)和极差(Tsmax-min);测量QRS波起点到射血波起点的时间(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:Ts-SD、Tsmax-min和TSI在对照组和CHF组分别为(8.5±4.3)ms vs(39.2±11.5)ms、22.2±12.6)ms vs(111.5±28.9)ms、(9.4±2.9)ms vs(23.1±6.6)ms(P值均＜0.0001).结论:QRS波＜120ms的心衰患者同样存在左室收缩不同步,故QRS波时限不能准确地反应左室运动的不同步性,而TVI技术可精确评价心室收缩的不同步性.     

Impact of pre-excitation syndrome on left ventricular systolic function and cardiac synchronization assessed by tissue Doppler imaging and speckle tracking techniques

BackgroundThe pathogenic mechanism for the development of left ventricular (LV) dysfunction in patients with asymptomatic pre-excitation syndrome has not yet been fully elucidated. We sought to assess the impact of pre-excitation on LV systolic function and whether the use of tissue Doppler imaging (TDI) and speckle tracking is more helpful in detection of the LV dyssynchrony than conventional echo parameters in these patients.MethodsThis observational case control study was carried out on adults with manifest pre-excitation syndromes. A detailed echocardiographic assessment was performed including TDI and speckle tracking examination.ResultsOur study patients were divided into two groups, group 1: with lateral accessory pathways (AP) (23 patients aged 31.65 ± 6.5 years), group 2: with septal AP (25 patients, 34.84 ± 10.8 years). Echocardiography showed a lower ejection fraction (EF) in group 2 than in group 1 (0.60 ± 0.07% in group 1 vs. 0.50 ± 0.08% in group 2, p = 0.000). The radial strain dyssynchrony index was higher in group 2 than in group 1 (58.78 ± 33.47 vs. 139.52 ± 21.14 ms; p < 0.0001) with a significant negative correlation with EF (r = −0.8, p = 0.000). Dyssynchrony detection was higher using speckle tracking technique than M mode/Doppler methods (p = 0.006).ConclusionPatients with pre-excitation syndrome may have depressed LV function unrelated to tachyarrhythmia, especially if the AP has a septal location. This dysfunction may be associated with the LV dyssynchronus contraction caused by pre-excitation. The use of TDI and speckle tracking echocardiographic techniques may be associated with an increase in the identification of manifest pre-excitation patients with significant LV dyssynchrony.     

Utility of three-dimensional echocardiography in assessing and predicting response to cardiac resynchronization therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) can be a valuable treatment for heart failure. However, there are high nonresponse rates using current CRT inclusion criteria.

OBJECTIVE

To assess the value of three-dimensional echocardiography (3DE) in predicting response to CRT.

METHODS

Functional assessments and 3DE were performed in heart failure patients pre-CRT, 24 h post-CRT and six to 12 months after CRT. The dyssynchrony index (DI) was calculated as the SD of the time to minimum volume in 16 left ventricle segments corrected by heart rate. Response to CRT was defined as functional improvement (alive at late follow-up with improvement by one New York Heart Association class) and a decrease in left ventricular end-systolic volume by 15% or greater at six to 12 months follow-up.

RESULTS

A total of 53 patients were enrolled. Average 3DE acquisition time was less than 5 min. Seventy-two per cent of patients showed functional improvement, while 43% showed functional and echocardiographic evidence of response. Baseline DI and the decrease in DI at 24 h were both correlated with reverse remodelling. Responders had higher baseline DI values compared with nonresponders (mean 16.8 versus 7.1, P<0.001), and showed a greater decrease in DI values at 24 h (mean decrease 7.9 versus 0.7, P<0.001). All responders had baseline DI values of greater than 10 (negative predictive value of 100%). A decrease in the DI value by more than 5 at 24 h in patients with a baseline DI of greater than 10 identified responders with a positive predictive value of 83%.

CONCLUSIONS

3DE may be valuable in predicting response to CRT. A baseline DI cut-off of greater than 10 in our patients excluded reverse remodelling to CRT. In addition, the decrease in DI at 24 h had a high positive predictive value for long-term response to CRT.