New Approach for Rotational Dyssynchrony Using Three‐Dimensional Speckle Tracking Echocardiography

Left ventricular (LV) twist can be evaluated using two‐dimensional speckle tracking echocardiography (2DSTE) by analyzing difference between apical and basal rotation. However, it is unable to evaluate global rotational dyssynchrony because it cannot assess mid‐wall rotation. Recently developed three‐dimensional STE (3DSTE) can investigate LV global rotational dyssynchrony. In this study, we investigated the role of torsion on the long‐term effects of cardiac resynchronization therapy (CRT) using 3DSTE. We evaluated 43 patients by 3DSTE: 12 CRT responders, 14 CRT nonresponders, and 17 healthy normal controls. Regional torsion and rotation were assessed using 3DSTE across 16 segments during CRT‐off (native conduction) and CRT‐on. The following parameters were calculated: global peak twist, Δ global peak twist (difference between CRT‐on and CRT‐off), and torsion delay index. The torsion delay index was considered to be the rotational energy lost by rotational dyssynchrony. Global peak twist did not show significant differences between the responders and nonresponders during CRT‐off (4.0 ± 3.4° vs. 2.8 ± 2.3°, P = 0.295), but it significantly improved in responders compared to nonresponders after CRT‐on (5.4 ± 3.5° vs. 2.6 ± 2.6°, P = 0.029). The torsion delay index during CRT‐off was significantly higher in responders compared to nonresponders and normal controls (18.5 ± 11.3 vs. 8.6 ± 3.8 and 7.8 ± 5.5, P = 0.010 and P = 0.004, respectively). The torsion delay index during CRT‐off significantly correlated with the Δ global peak twist (r = 0.503, P = 0.009). Improvement in LV global peak twist, which is one of the mechanisms for the long‐term effects of CRT correlated with the torsion delay index during native conduction that can only be calculated by 3DSTE.     

Left ventricular dyssynchrony using three-dimensional speckle-tracking imaging as a determinant of torsional mechanics in patients with idiopathic dilated cardiomyopathy

The aim of this study was to use 3-dimensional (3D) speckle-tracking echocardiography to test the hypothesis that left ventricular (LV) dyssynchrony may negatively affect LV torsional mechanics in patients with idiopathic dilated cardiomyopathy (IDC) and that LV torsion may improve after cardiac resynchronization therapy. This study included 65 subjects; 20 with IDC with ejection fractions ≤35% and wide QRS complexes (≥120 ms), 20 with IDC with ejection fractions ≤35% and narrow QRS complexes (<120 ms), and 25 controls. LV dyssynchrony index was determined as the SD of time to peak 3D speckle-tracking radial strain and regional heterogeneity of LV rotation (rotational dispersion index) as the SD of 3D speckle-tracking time to peak rotation. All rotational indexes were significantly impaired in patients with IDC, while LV torsion in patients with IDC with wide QRS complexes was significantly smaller than that in patients with IDC with narrow QRS complexes and controls. Conversely, LV dyssynchrony index (127.3 ± 24.0 ms [p <0.01 vs controls and vs patients with narrow QRS complexes] vs 88.8 ± 22.5 ms [p <0.01 versus controls] vs 30.9 ± 10.0 ms) and rotational dispersion index (115.1 ± 27.5 ms [p <0.01 vs controls and vs patients with narrow QRS complexes] vs 96.0 ± 23.4 ms [p <0.01 versus controls] vs 45.0 ± 13.7 ms) were significantly higher in patients with IDC with wide QRS complexes. Multivariate analysis showed that the LV ejection fraction (β = 0.688, p <0.001) and rotational dispersion index (β = -0.249, p <0.01) were independent determinants of LV torsion. Moreover, LV torsion in patients with IDC with wide QRS complexes improved after cardiac resynchronization therapy (p <0.05), along with reductions in LV dyssynchrony and rotational dispersion indexes. In conclusion, these findings obtained with a novel 3D speckle-tracking system feature a novel aspect of LV torsional mechanics and demonstrate its association with LV dyssynchrony.     

Adult definitions for dyssynchrony are inappropriate for pediatric patients

Background: Cardiac resynchronization therapy (CRT) is a promising approach to improve cardiac function in children in heart failure with cardiomyopathy. Cardiac timing measures in pediatrics are typically based on age and heart rate. However, pediatric CRT studies to date have used adult based timing cutoff values. We investigated the applicability of using these adult standards in pediatric patients with normal hearts. Methods: We studied 88 outpatients referred for cardiac evaluation who had a normal cardiac evaluation. Subjects had 12 lead EKG and normal echocardiogram. Patients with known heart disease or abnormal rhythms were excluded. 2D echo and Doppler including color tissue Doppler imaging (TDI, Vivid 7 GE Ultrasound, Norway) were obtained. TDI was performed on three standard apical views (four chamber, two chamber, and long axis). Longitudinal dyssynchrony was determined from (1) Yu index – standard deviation of differences in timing of peak TDI velocity of all 12 basal and mid LV wall segments, adult cutoff >32 ms and (2) opposing wall difference (OWD) in timing of peak TDI velocity of 12 LV wall segments, adult cutoff >65 ms. Radial dyssynchrony was determined from differences in timing of peak radial strain between anterior‐septal and posterior LV segments from speckle tracking of 2D LV views, adult cutoff >130 ms. Results: Median age was 11.5 years; median heart rate was 74.5. Longitudinal dyssynchrony was present in 40% of normals based on Yu index, and in 43% based on OWD. No child had Radial dyssynchrony. Conclusions: This pilot study of children with normal hearts suggests that current adult CRT dyssynchrony cutoff values are inappropriate in the pediatric population. (Echocardiography 2011;28:468‐474)     

Chronic Effect of Right Ventricular Pacing on Left Ventricular Rotational Synchrony in Patients with Complete Atrioventricular Block

Background: Chronic effect of right ventricular (RV) pacing on left ventricular (LV) rotational synchrony is unknown. The aim of this study is to assess chronic effect of RV pacing on LV rotational synchrony using two‐dimensional ultrasound speckle tracking imaging. Methods and Results: Thirty‐one patients who underwent dual‐chamber pacemaker implantation for complete atrioventricular block, and age‐ and sex‐matched 10 healthy controls were assessed. We divided our patients into RV apical (RVA, n = 16) and RV outflow tract (RVOT, n = 15) pacing groups. We compared echocardiographic parameters such as LV rotational synchrony between pacing groups and healthy control. We defined Q to peak rotation interval as the interval from the beginning of the Q‐wave to the peak apical counter‐clockwise or peak basal clockwise rotation. We calculated apical–basal rotation delay by subtracting basal Q to peak rotation interval from apical one as the representative of rotational synchronization. Apical–basal rotation delay of RVA pacing was significantly longer than that of healthy control (100 ± 110 vs. ?6 ± 15 ms, P = 0.002), while there was no statistically significant difference between RVOT pacing and healthy control (?3 ± 99 vs. ?6 ± 15 ms, P = 0.919). Conclusions: LV rotation during RVOT pacing is synchronous at 15 months after pacemaker implantation, while RVA pacing provokes LV rotational dyssynchrony by inducing delayed apical rotation at 7 years after pacemaker implantation in patients with complete atrioventricular block. (Echocardiography 2011;28:69‐75)     

Pulmonary Hypertension Affects Left Ventricular Basal Twist: A Novel Use for Speckle-Tracking Imaging

Background: Chronic pulmonary hypertension (PH) results in right ventricular (RV) mechanical dyssynchrony. However, its effects on left ventricular (LV) mechanics have not been examined. Objective: Since speckle-tracking echocardiography (STE) is a novel approach to quantify LV dyssynchrony; we decided to use STE to assess the effect of PH on LV mechanics. Methods: Our echocardiography database was queried for patients with PH who had undergone STE analysis and compared to similarly collected data from a group of healthy volunteers. Results: Group I (15 patients, age of 53 ± 17 years, pulmonary artery pressure of 62 ± 20 mmHg, eccentricity index of 0.78 ± 0.06, and LV ejection fraction of 64 ± 11%) and Group II (8 healthy volunteers, age 41 ± 9 years, pulmonary artery pressure 14.6 ± 4.2 mmHg, eccentricity index of 1.02 ± 0.05, and LV ejection fraction of 66 ± 6 mmHg). There was no difference in QRS duration between the two groups. Although PH significantly altered basal LV twist (Group I: M =−5.76° versus Group II: M =−1.82°, P < 0.05), it had no effect on LV apical twist (5.29° versus 4.50°; P = NS, respectively). More notably, significant LV radial basal LV dyssynchrony, measured as the time to peak LV basal twist, was seen as a result of PH. Conclusions: STE identifies the presence of LV dyssynchrony in PH despite normal LV ejection fraction and no difference in QRS duration. Additional studies are now required to further characterize these results and determine their prognostic significance.     

Combined longitudinal and radial dyssynchrony predicts ventricular response after resynchronization therapy.

OBJECTIVES: The purpose of this study was to test the hypothesis that a combined echocardiographic assessment of longitudinal dyssynchrony by tissue Doppler imaging (TDI) and radial dyssynchrony by speckle-tracking strain may predict left ventricular (LV) functional response to cardiac resynchronization therapy (CRT). BACKGROUND: Mechanical LV dyssynchrony is associated with response to CRT; however, complex patterns may exist. METHODS: We studied 190 heart failure patients (ejection fraction [EF] 23 +/- 6%, QRS duration 168 +/- 27 ms) before and after CRT. Longitudinal dyssynchrony was assessed by color TDI for time to peak velocity (2 sites in all and 12 sites in a subgroup of 67). Radial dyssynchrony was assessed by speckle-tracking radial strain. The LV response was defined as > or =15% increase in EF. RESULTS: One hundred seventy-six patients (93%) had technically sufficient baseline and follow-up data available. Overall, 34% were EF nonresponders at 6 +/- 3 months after CRT. When both longitudinal dyssynchrony by 2-site TDI (> or =60 ms) and radial dyssynchrony (> or =130 ms) were positive, 95% of patients had an EF response; when both were negative, 21% had an EF response (p < 0.001 vs. both positive). The EF response rate was lowest (10%) when dyssynchrony was negative using 12-site TDI and radial strain (p < 0.001 vs. both positive). When either longitudinal or radial dyssynchrony was positive (but not both), 59% had an EF response. Combined longitudinal and radial dyssynchrony predicted EF response with 88% sensitivity and 80% specificity, which was significantly better than either technique alone (p < 0.0001). CONCLUSIONS: Combined patterns of longitudinal and radial dyssynchrony can be predictive of LV functional response after CRT.     

Measures of left ventricular dyssynchrony and the correlation to clinical and echocardiographic response after cardiac resynchronization therapy

There is still no standardized measure of left ventricular (LV) dyssynchrony or definition of response in candidates of cardiac resynchronization therapy (CRT). Recipients of CRT underwent echocardiographic assessment of LV dyssynchrony before and immediately after implantation of a CRT device. Patients were followed for 6 months postimplantation. A total of 44 patients (64 +/- 12 years, 30 men, and 26 with ischemic cardiomyopathy) were included in this analysis. There was a significant decrease in both radial (304 +/- 137 vs 121 +/- 85 ms, p <0.001) and longitudinal (143 +/- 104 vs 95 +/- 43 ms, p = 0.02) measures of LV dyssynchrony immediately after CRT. The immediate post-CRT change in radial (r = -0.43, p = 0.015) but not longitudinal (r = -0.09, p = 0.61) LV dyssynchrony correlated with a significant improvement in the physical component of the quality-of-life score 6 months after CRT. Although a higher baseline longitudinal (p = 0.05) or radial (p = 0.025) LV dyssynchrony predicted a >or=1 improvement in New York Heart Association classification of heart failure 6 months after CRT, acute changes in neither radial (p = 0.71) nor longitudinal (p = 0.89) LV dyssynchrony were predictive of any improved echocardiographic outcomes in follow-up. Concordance between clinical and echocardiographic response to CRT was documented in 72% of patients. In conclusion, both longitudinal and radial measures of LV dyssynchrony improve after CRT. The change in longitudinal but not radial measures of LV dyssynchrony correlates with improved physical quality-of-life score in intermediate term follow-up.     

Tricuspid Annular Plane Systolic Excursion Evaluation Improves Selection of Cardiac Resynchronization Therapy Patients

Background

The beneficial effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) remodeling have been extensively described. Few data are available about the effects of CRT on right ventricular (RV) function and remodeling.

Hypothesis

We hypothesized that CRT could also induce reverse remodeling in the right ventricle and that RV baseline functional status expressed as tricuspidal annular plane systolic excursion (TAPSE) could affect CRT response.

Methods

Echocardiographic investigation was performed before and 6 months after CRT. In 192 patients, TAPSE, LV, and RV dimensions with functional parameters and LV dyssynchrony index were evaluated.

Results

At 6 months' follow‐up, 86 patients (45%) were responders to CRT according to at least 15% LV end‐systolic volume reduction. Among baseline echocardiographic parameters, responders had significantly lower TAPSE, larger LV volumes, and higher LV dyssynchrony index. In responders, LV volume reduction, ejection fraction increase, and mitral regurgitation improvement were associated with RV dimensions reduction, increased TAPSE, and improved LV dyssynchrony. Receiver operating characteristic curve analysis showed that TAPSE, at 17 mm optimal cutoff, yielded 64% sensitivity and 60% specificity in predicting CRT response; similarly, LV dyssynchrony index, at 41.25 ms optimal cutoff, predicted CRT response with 60% sensitivity and 62% specificity. A subgroup analysis demonstrated that the coexistence of high TAPSE and high dyssynchrony index values increased probability of CRT response.

Conclusions

Our results show that CRT induces RV and LV reverse remodeling and that CRT patient selection can be improved by simply measuring TAPSE value. Copyright © 2010 Wiley Periodicals, Inc. The authors have no funding, financial relationships, or conflicts of interest to disclose.     

Mechanism of improvement in mitral regurgitation after cardiac resynchronization therapy.

AIMS: The aim of the current study was to evaluate the relationship between the presence of left ventricular (LV) dyssynchrony at baseline and acute vs. late improvement in mitral regurgitation (MR) after cardiac resynchronization therapy (CRT). METHODS AND RESULTS: Sixty eight patients consecutive (LV ejection fraction 23 +/- 8%) with at least moderate MR (>or=grade 2+) were included. Echocardiography was performed at baseline, 1 day after CRT initiation and at 6 months follow-up. Speckle tracking radial strain was used to assess LV dyssynchrony at baseline. The majority of patients improved in MR after CRT, with 43% improving immediately after CRT, and 20% improving late (after 6 months) after CRT. Early and late responders had similar extent of LV dyssynchrony (209 +/- 115 ms vs. 190 +/- 118 ms, P = NS); however, the site of latest activation in early responders was mostly inferior or posterior (adjacent to the posterior papillary muscle), whereas the lateral wall was the latest activated segment in late responders. CONCLUSION: Current data suggest that the presence of baseline LV dyssynchrony is related to improvement in MR after CRT. LV dyssynchrony involving the posterior papillary muscle may lead to an immediate reduction in MR, whereas LV dyssynchrony in the lateral wall resulted in late response to CRT.     

Left intraventricular myocardial deformation dyssynchrony identifies responders to cardiac resynchronization therapy in patients with heart failure.

AIMS: We tested the hypothesis that dyssynchrony of left ventricular (LV) myocardial deformation evaluated by ultrasound can predict success of cardiac resynchronization therapy (CRT) in patients with heart failure (HF). METHODS AND RESULTS: Thirty-seven patients with dilated cardiomyopathy, New York Heart Association class III-IV, LV ejection fraction (EF) < or =35%, QRS > 120 ms were studied before, at pre-discharge, and after 3 and 6 months of CRT. The M-mode peak septal-to-posterior wall motion and thickening delay (SPWMD and SPWTD, ms) and the standard deviation of the averaged time-to-peak strain (TPS-SD, ms) of 12 middle and basal LV segments obtained from the three standard apical views were calculated. Responders were defined at month 6 by > or =20% EF increase and/or > or =15% end-systolic volume (ESV) decrease with respect to baseline. Baseline SPWTD (not SPWMD) and TPS-SD differentiated responders from non-responders with good accuracy and reproducibility. A value > or =194 ms for SPWTD and > or =60 ms for TPS-SD was significantly associated with responder identification. Baseline dyssynchrony parameters correlated significantly with EF (r = 0.53 for SPWTD and r = 0.86 for TPS-SD) and ESV variations (r = -0.42 for SPWTD and r = -0.73 for TPS-SD). CONCLUSION: Patients with chronic HF should undergo ultrasound evaluation to quantify dyssynchrony of LV myocardial deformation, which would help identifying CRT responders.     

The mechanics of left ventricular dysfunction in patients with Churg-Strauss syndrome

Background: Heart is frequently involved in Churg‐Strauss syndrome (CSS). However, the mechanics of left ventricular (LV) dysfunction in CSS has not been studied. Objective: To assess the mechanics of LV function and to characterize the contribution of longitudinal, circumferential and rotational deformation to LV dysfunction in CSS. Methods: We enrolled 22 CSS patients (eight males, mean age 43.2 ± 9.5 years) in remission of their disease and 22 sex‐ and age‐matched healthy subjects. All patients underwent conventional and two‐dimensional speckle‐tracking echocardiography. Global longitudinal, circumferential and rotational deformation parameters were calculated. Results: CSS subjects demonstrated lower LV ejection fraction (EF) than controls (56.6 ± 15.0% vs 63.8 ± 3.4%; P < 0.05). When compared to those with LVEF ≥ 50% (n = 14), CSS patients with LVEF < 50% (n = 7) had decreased global peak‐systolic longitudinal and circumferential strain/strain rate (all P < 0.001) and tended to have lower global peak‐systolic radial strain (P = 0.05). There were no differences between these two subgroups in global peak‐systolic radial strain rate and LV twist/torsion. When comparing individual systolic and diastolic parameters early diastolic longitudinal and circumferential strain rate demonstrated the highest correlation with corresponding global longitudinal and circumferential peak‐systolic strain/strain rate (r < ?0.80, P < 0.001 for all correlations). Conclusions: In CSS LV systolic dysfunction strongly correlates with longitudinal and circumferential, but not radial or rotational systolic components, indicating that impaired LV systolic function may result predominantly from impaired contraction of inner and middle, but not outer myocardial fiber layers. The spatial correspondence between systolic and diastolic deformation parameters suggests the similar impact of pathologic process on systolic and diastolic function in CSS. (Echocardiography 2012;29:568‐578)     

The Echocardiographic Assessment of Dyssynchrony: Insights from a Consecutive Series of General Cardiology Patients with Normal LVEF and Narrow QRS

Background: Prior studies have described the potential benefit of using echocardiographic rather than ECG techniques to help select the subgroup of heart failure patients that are most likely to benefit from cardiac resynchronization therapy (CRT). Currently, the most commonly used echocardiographic techniques to assess dyssynchrony include discrepancies in radial motion derived from M-mode and in longitudinal motion derived from tissue Doppler; however, there are little data available on the range of these measurements in the general cardiology population. Methods and Results: A consecutive series of patients referred for a stress echocardiogram were screened for normal LV systolic function and normal QRS width. Fifty-one patients met inclusion criteria and underwent dyssynchrony measurements in addition to their baseline echo. Previously proposed cutoff values were applied. We observed 17% of study subjects were above the reported normal values for radial dyssynchrony and 41% were above the reported normal values for longitudinal dyssynchrony. However, when both criteria were required to be abnormal only 4% were classified as dyssynchronous. Conclusions: Echocardiographic indices in general cardiology patients appear most accurate when radial and longitudinal parameters are used in combination. While the ideal cutoff values remain to be determined, this combination may optimize patient selection for CRT response.     

Assessment of left ventricular twist mechanics by two-dimensional strain in severe aortic stenosis with preserved ejection fraction

Left ventricular (LV) twist is increased in aortic stenosis (AS) and the hypothesis of a compensatory mechanism is suggested but not established. Our aim was to assess LV twist mechanics in severe AS (< 1 cm² or 0.6 cm²/m²) with preserved LV ejection fraction (LVEF > 50%), and to analyze its relationship with LV systolic longitudinal function, early impaired in this setting, LV diastolic function, and symptomatic status.MethodsForty-five consecutive patients with severe AS and preserved LVEF (mean age 73 ± 11 years, 47% female, LVEF 68 ± 11%, 67% symptomatic) underwent a transthoracic echocardiography including a bidimensional strain analysis by speckle tracking method, and were compared to a control group matched for age and sex (n = 15). Global longitudinal strain (GLS) was measured using the four, two, and three apical views, and LV twist mechanics from the basal and apical short axis views. LV twist was defined as the net difference between apical and basal rotation, and LV twisting and untwisting rate (in °/s) were derived from twist curves.ResultsPeak apical rotation, LV twist (25 ± 8° vs 20 ± 6), as well as peak systolic and diastolic apical rotation rate, and peak LV twisting rate were significantly higher in patients with AS when compared to controls (all, P < 0.05), whereas, the other parameters of LV twist mechanics including basal rotation, were not significantly different between groups. By contrast, the GLS was significantly lower in patients with AS when compared to controls (–17.9 ± 4 vs –20.5 ± 2%, P < 0.01). In addition, the GLS was significantly correlated to LV torsion (r = –0.42, P < 0.01). Moreover, LV twist progressively impaired with the worsening of diastolic dysfunction and with symptoms onset.ConclusionLV twist is increased in severe AS with preserved LVEF, compensating the impairment of systolic longitudinal function. However, above a certain threshold LV twist deteriorates, attesting the failure of the compensatory mechanisms, leading to advanced diastolic dysfunction and symptom onset.     

Left ventricular dyssynchrony predicts response and prognosis after cardiac resynchronization therapy

OBJECTIVES: This study was designed to predict the response and prognosis after cardiac resynchronization therapy (CRT) in patients with end-stage heart failure (HF). BACKGROUND: Cardiac resynchronization therapy improves HF symptoms, exercise capacity, and left ventricular (LV) function. Because not all patients respond, preimplantation identification of responders is needed. In the present study, response to CRT was predicted by the presence of LV dyssynchrony assessed by tissue Doppler imaging. Moreover, the prognostic value of LV dyssynchrony in patients undergoing CRT was assessed. METHODS: Eighty-five patients with end-stage HF, QRS duration >120 ms, and left bundle-branch block were evaluated by tissue Doppler imaging before CRT. At baseline and six months follow-up, New York Heart Association functional class, quality of life and 6-min walking distance, LV volumes, and LV ejection fraction were determined. Events (death, hospitalization for decompensated HF) were obtained during one-year follow-up. RESULTS: Responders (74%) and nonresponders (26%) had comparable baseline characteristics, except for a larger dyssynchrony in responders (87 +/- 49 ms vs. 35 +/- 20 ms, p < 0.01). Receiver-operator characteristic curve analysis demonstrated that an optimal cutoff value of 65 ms for LV dyssynchrony yielded a sensitivity and specificity of 80% to predict clinical improvement and of 92% to predict LV reverse remodeling. Patients with dyssynchrony >/=65 ms had an excellent prognosis (6% event rate) after CRT as compared with a 50% event rate in patients with dyssynchrony <65 ms (p < 0.001). CONCLUSIONS: Patients with LV dyssynchrony >/=65 ms respond to CRT and have an excellent prognosis after CRT.     

Real-time three-dimensional echocardiography permits quantification of left ventricular mechanical dyssynchrony and predicts acute response to cardiac resynchronization therapy

Objective: To evaluate the value of real-time three-dimensional echocardiography (RT3DE) to predict acute response to cardiac resynchronization therapy (CRT).
Methods: Sixty consecutive heart failure patients scheduled for CRT were included. RT3DE was performed before and within 48 hours after pacemaker implantation to calculate both left ventricular (LV) volumes and LV dyssynchrony. LV dyssynchrony was defined as the standard deviation of the time taken to reach the minimum systolic volume for 16 LV segments (referred to as the systolic dyssynchrony index, SDI). Patients were subsequently divided into acute responders or nonresponders, based on a reduction ≥ 15% in LV end-systolic volume immediately after CRT.
Results: Four patients (7%) were excluded from further analysis because of either suboptimal apical acquisitions or significant translation artifacts. Out of the remaining 56 patients, 35 patients (63%) were classified as acute responders. Baseline characteristics were similar between responders and nonresponders, except for the SDI, which was larger in responders. Moreover, responders demonstrated a significant reduction of SDI immediately after CRT (from 9.7 ± 4.1% to 3.6 ± 1.8%, P < 0.0001), whereas SDI did not change in nonresponders (3.4 ± 1.8% vs 3.1 ± 1.1%, NS). ROC curve analysis revealed that a cut-off value for SDI of 5.6% yielded a sensitivity of 88% with a specificity of 86% to predict acute echocardiographic response to CRT (AUC 0.96).
Conclusion: RT3DE is highly predictive for acute response to CRT (sensitivity 88% and specificity 86%). In addition, RT3DE allows assessment of changes in LV volumes and LV ejection fraction before and after CRT implantation.     

Differences in Left Ventricular Twist Related to Age: Speckle Tracking Echocardiographic Data for Healthy Volunteers from Neonate to Age 70 Years

Objective: To determine normal left ventricular (LV) twist characteristics in different age groups and assess changes between neonates and the elderly. Methods: Short‐axis left ventricle images at basal and apical levels were acquired in 274 healthy volunteers (aged 15 days to 72 years) by two‐dimensional echocardiography, and were analyzed off‐line using Speckle tracking echocardiography (STE) software to obtain LV twist measurements. The peak apical rotation (PAr), peak basal rotation (PBr), peak LV twist (Ptw), peak LV twist normalized by LV length (Ptw N ), peak untwisting velocity (PutwV), and isovolumic untwisting% (Iutw%) were measured. Results: LV twist values vary with age. Ptw was higher in older volunteers. PtwN varied inconsistently with age. PutwV and Iutw% were lower in the young and old with a peak in mid–age ranges. Conclusions: STE is an effective noninvasive method to assess LV twist. Age‐related differences in LV twist may reflect maturation and adaptive modulation of LV torsional biomechanics from neonate to the elderly. (Echocardiography 2010;27:1205‐1210)     

斑点追踪显像对冠心病经皮冠状动脉介入治疗后的疗效评价简

目的 探讨二维超声斑点追踪显像技术（two-dimensional speckle tracking imaging,2DSTI）评价冠状动脉粥样硬化性心脏病（冠心病）患者经皮冠状动脉介入（percutaneous coronary intervention,pCI）治疗后效果的临床应用价值.方法 经冠状动脉造影（coronary angiography,CAG）证实左前降支狭窄＞75％的40例非心肌梗死患者,分别于PCI治疗前1周内和治疗后3个月获取左心室短轴观二尖瓣环水平、乳头肌水平、心尖水平及心尖四腔观、二腔观,左心室长轴观的高帧频二维超声心动图,应用斑点追踪显像（speckle tracking imaging,STI）软件,检测其相关供血心肌节段的收缩期纵向、径向、圆周峰值应变以及左心室基底部、心尖部旋转角度和左心室整体扭转角度.结果 PCI治疗前应变-时间曲线形态紊乱,多数节段波峰低平.在PCI治疗后3个月,缺血心肌节段的轮廓趋向规则,波峰明显升高.左心室大部分节段纵向收缩期峰值应变较术前明显增加,差异有统计学意义（P＜0.05）.各组左心室短轴收缩期峰值径向应变、圆周应变无明显改善,差异无统计学意义（P＞0.05）.左心室收缩期心尖部最大旋转角度及整体扭转角度均较术前明显升高,差异有统计学意义（P＜0.05）.结论 应用2DSTI可定量评价左心室心肌的局部和整体功能,为冠心病患者PCI治疗后疗效的观察提供一种经济、简便、无创的检查方法.     

Prediction of response to cardiac resynchronization therapy combining two different three-dimensional analyses of left ventricular dyssynchrony

Triplane tissue synchronization imaging (TSI) and real-time 3-dimensional echocardiography (RT3DE) provide different characterizations of left ventricular (LV) mechanics and dyssynchrony. Triplane TSI assesses differences in time to peak systolic segmental myocardial tissue velocities, whereas RT3DE evaluates differences in time to minimum end-systolic regional volumes. Whether an approach using the 2 3D techniques predicts better significant reverse remodeling after cardiac resynchronization therapy (CRT) remains unknown. In 166 patients (mean age 66 ± 9 years, 78% men) treated with CRT, baseline LV dyssynchrony was assessed using RT3DE and triplane TSI. LV dyssynchrony was defined by a systolic dyssynchrony index ≥6.4% when assessed with RT3DE and SD of time to peak velocity of 12 segments (Ts-SD-12) ≥33 ms with triplane TSI. CRT response was defined by ≥15% decrease in LV end-systolic volume at 6-month follow-up. Mean LV dyssynchrony using Ts-SD-12 was 48 ± 26 ms and mean systolic dyssynchrony index was 8.51 ± 3.81%. Response to CRT was observed in 86.3% of patients showing LV dyssynchrony with the 2 methods. In contrast, 97% of patients who did not show significant LV dyssynchrony with any of the techniques were nonresponders (p <0.001). Importantly, systolic dyssynchrony index and LV dyssynchrony using Ts-SD-12 were independent predictors of response to CRT (p <0.001 for each technique). Assessment of LV dyssynchrony with the 2 techniques showed incremental value for prediction of significant LV reverse remodeling over its assessment with only 1 technique (chi-square 90.18, p <0.001). In conclusion, the combined use of 2 different 3D techniques to assess LV dyssynchrony permits accurate prediction of response to CRT.     

Utility of comprehensive assessment of strain dyssynchrony index by speckle tracking imaging for predicting response to cardiac resynchronization therapy

The strain delay index is reportedly a marker of dyssynchrony and residual myocardial contractility. The aim of this study was to test the hypothesis that a relatively simple version of the strain dyssynchrony index (SDI) can predict response to cardiac resynchronization therapy (CRT) and that combining assessment of radial, circumferential, and longitudinal SDI can further improve the prediction of responders. A total of 52 patients who underwent CRT were studied. The SDI was calculated as the average difference between peak and end-systolic strain from 6 segments for radial and circumferential SDI and 18 segments for longitudinal SDI. Conventional dyssynchrony measures were assessed by interventricular mechanical delay, the Yu index, and radial dyssynchrony by speckle tracking strain. Response was defined as a ≥15% decrease in end-systolic volume after 3 months. Of the individual parameters, radial SDI ≥6.5% was the best predictor of response to CRT, with sensitivity of 81%, specificity of 81%, and an area under the curve of 0.87 (p <0.001). Circumferential SDI ≥3.2% and longitudinal SDI ≥3.6% were also found to be predictive of response to CRT, with areas under the curve of 0.81 and 0.80, respectively (p <0.001). Moreover, radial, circumferential, and longitudinal SDI at baseline were correlated with reduction of end-systolic volume with CRT. In addition, the response rate in patients with 3 positive SDIs was 100%. In contrast, rates in patients with either 1 or no positive SDIs were 42% and 22%, respectively (p <0.005 and p <0.001 vs 3 positive SDIs). In conclusion, the SDI can successfully predict response to CRT, and the combined approach leads to more accurate prediction than using individual parameters.     

The Role of Speckle Tracking Strain Imaging in Cardiac Pacing

In recent years, concerns have been raised about possible harmful effects of long-term right ventricular (RV) apical pacing. These detrimental effects may be related to changes in left ventricular (LV) mechanics during RV apical pacing. As a consequence, alternative RV pacing sites have been proposed, and in selected patients an upgrade from RV to biventricular pacing may be considered. Novel two-dimensional (2D) speckle tracking strain imaging allows detailed evaluation of LV mechanics, including LV mechanical dyssynchrony, LV strain and LV torsion. In this review, the role of speckle tracking strain imaging in the evaluation of LV function in patients with RV apical pacing will be reviewed. The effects of RV apical pacing on LV mechanical dyssynchrony, LV strain and LV torsion will be discussed. In addition, the role of speckle tracking strain imaging in the selection of the optimal (alternative) RV pacing site and in the selection of patients who may benefit from an upgrade from RV apical pacing to biventricular pacing will be reviewed.