斑点追踪显像评价左室旋转运动的研究进展

心动周期中心尖及心底沿左室长轴向不同方向旋转,引起心脏扭曲或扭转运动。心肌纤维的螺旋状排列是联系心脏旋转运动解剖学与生理学机制的基础。斑点追踪显像可检测心脏扭转运动,对预测及治疗心肌功能障碍提供有价值的信息,是评价心脏旋转运动的新超声心动图技术。     

Apical Left Ventricular Hypertrophy and Mid‐Ventricular Obstruction in Fabry Disease

We report the case of a rare cardiac presentation of Fabry disease. Although concentric left ventricular hypertrophy is a major cardiac finding in Fabry disease, there is no case report of dynamic obstruction at mid‐left ventricular level. We describe a 59‐year‐old‐woman suffering from a severe form of Fabry disease, mimicking an apical hypertrophic cardiomyopathy with mid‐ventricular obstruction. Differentiation of Fabry disease from hypertrophic cardiomyopathy is crucial given the therapeutic and prognostic differences. Fabry disease should always be suspected in an adult, independently of the pattern of left ventricular hypertrophy.     

Speckle Tracking in the Evaluation of Left Ventricular Dyssynchrony

A number of echocardiographic techniques have been introduced to determine left ventricular dyssynchrony (LVD) and to improve selection of patients for CRT . During the last years tissue Doppler imaging (TDI) has been used as the most preferred technique to quantify LVD, but results with nonresponder rates below 30% have been shown only in small studies based on high experience. Angle of incidence dependency, noise, artifacts, and tethering motion of adjacent segments are the main limitations of TDI influencing selection of patients for CRT. Although strain TDI is not affected by translation or tethering, accurate measurement of regional strain is also limited. Two-dimensional (2D) strain imaging based on novel speckle tracking echocardiography (STE) is a relatively new tool to define regional myocardial strain and to quantify dyssynchrony based on a more robust technique and avoiding angle of incidence. Current studies are promising to use strain or vector velocity imaging derived from STE for qualitative and quantitative assessment of LVD and follow-up studies as well. If one compare different types of strain components at present, radial strain imaging seems to be the most promising technique to determine LVD and to predict positive response to CRT. Furthermore, STE offers an insight into rotational mechanics of the dyssynchronous ventricle. Although clinical studies using 2D strain have analyzed LVD related to various conditions, measures are based on a 2D data set. Three-dimensional strain imaging, based on speckle tracking will probably open a new door to assess patients with heart failure and LVD.     

Left Ventricular Dyssynchrony by Three‐Dimensional Echocardiography: Current Understanding and Potential Future Clinical Applications

Left ventricular mechanical dyssynchrony is an important prognostic factor for patients with symptomatic systolic heart failure and has emerged as a therapeutic target for cardiac resynchronization therapy (CRT). However, approximately one‐third of patients fail to improve after CRT based on current guideline recommendations and electrocardiographic criteria. Two‐dimensional echocardiography and tissue Doppler–based techniques have shown variable results in assessment of left ventricular (LV) dyssynchrony and have limited value in clinical practice. Three‐dimensional echocardiography (3DE) is an appealing novel imaging modality that has been recently used in quantitative evaluation of global and regional LV function. There is accumulating evidence that 3DE measurement of LV systolic dyssynchrony index may potentially play a role in predicting the short‐ and long‐term response to CRT and further improve patient selection for CRT. New developments in 3DE speckle tracking technique and strain analysis may further improve the accuracy of LV mechanical dyssynchrony assessment in this population. In addition, recent studies suggest that mechanical dyssynchrony is present in patients with LV hypertrophy and diastolic heart failure. Three‐dimensional echocardiographic assessment of dyssynchrony may aid in diagnosis and in predicting long‐term outcome in these patients. We will summarize current understanding of 3DE techniques and parameters in assessment of LV mechanical dyssynchrony in the population of patients with systolic heart failure, LV hypertrophy, and diastolic heart failure. A number of the novel 3DE techniques described in this review are early in their stage of development, and they will continue to evolve and need further testing in large multicenter studies.     

左室心尖气球样综合征的诊断与治疗现状

左室心尖气球样综合征主要表现为间歇性左心室功能障碍伴左室心尖部心肌气球样变,但无显著的冠状动脉疾病。现结合近年来发表的相关文献,对其病理生理学特征、临床表现、实验室检查以及治疗现状进行综述。     

Two‐Dimensional Ultrasound Speckle Tracking Imaging in Evaluation of Early Changes in Left Ventricular Diastolic Function in Patients with Essential Hypertension

Objective: To investigate two‐dimensional ultrasound speckle tracking imaging (STI) in evaluating values of early changes in left ventricular diastolic function in patients with essential hypertension (EH). Methods: Seventy‐five EH patients with left ventricular normal geometry (LVN), including 38 cases with nonleft atrial enlargement (NLAE) and 37 cases with left atrial enlargement (LAE), and 50 healthy persons were enrolled as study participants. Two‐dimensional images of LV apical four‐chamber view, two chamber view, and LV long‐axis view and short‐axis view of mitral annular, papillary muscle, and apical levels were obtained to measure early diastolic E′ peak value, late diastolic A′ peak value, and E′/A′ ratio at LV apical longitudinal strain rate (SrL) and short‐axis radial strain rate (SrR), circumferential strain rate (SrC), and rotation rate (RotR) in all cardiac segments. Average values of E′, A′, and E′/A′ at SrL in three segments on long‐axis and SrR, SrC, and RotR on three short‐axis levels were calculated. Untwisting rate (Untw R) and untwisting half‐time (UHT) were also calculated. Results: (1) Data on 110 of 125 patients were usable for STI analysis. (2) There were no intersegment significant differences between A′ at SrL in three segments or interlevel significant differences between A′ at SrR in three levels in the NLAE group and the LAE group. (3) Compared with the normal group, E′ at SrL and E′/A′ at SrL, SrR and SrC, and Untw R reduced in the NLAE group and the LAE group, while A′ at SrL, SrR, and SrC and E′ at RotR increased and UHT extended. Conclusion: STI may be helpful for the detection of early changes in left ventricular diastolic function in patients with EH. (ECHOCARDIOGRAPHY 2010;27:146‐154)     

Two‐ and Three‐Dimensional Speckle Tracking Echocardiography: Clinical Applications and Future Directions

Two‐dimensional speckle tracking echocardiography (2D STE) is a novel technique of cardiac imaging for quantifying complex cardiac motion based on frame‐to‐frame tracking of ultrasonic speckles in gray scale 2D images. Two‐dimensional STE is a relatively angle independent technology that can measure global and regional strain, strain rate, displacement, and velocity in longitudinal, radial, and circumferential directions. It can also quantify rotational movements such as rotation, twist, and torsion of the myocardium. Two‐dimensional STE has been validated against hemodynamics, tissue Doppler, tagged magnetic resonance imaging, and sonomicrometry studies. Two‐dimensional STE has been found clinically useful in the assessment of cardiac systolic and diastolic function as well as providing new insights in deciphering cardiac physiology and mechanics in cardiomyopathies, and identifying early subclinical changes in various pathologies. A large number of studies have evaluated the role of 2D STE in predicting response to cardiac resynchronization therapy in patients with severe heart failure. However, the clinical utility of 2D STE in the above mentioned conditions remains controversial because of conflicting reports from different studies. Emerging areas of application include prediction of rejection in heart transplant patients, early detection of cardiotoxicity in patients receiving chemotherapy for cancer, and effect of intracoronary injection of bone marrow stem cells on left ventricular function in patients with acute myocardial infarction. The emerging technique of three‐dimensional STE may further extend its clinical usefulness.     

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)     

Combined Baseline Strain Dyssynchrony Index and Its Acute Reduction Predicts Mid‐Term Left Ventricular Reverse Remodeling and Long‐Term Outcome after Cardiac Resynchronization Therapy

The objective of this study was to test the hypothesis that combining assessment of baseline radial strain dyssynchrony index (SDI), that expressed both left ventricular (LV) dyssynchrony and residual myocardial contractility, and of acute changes in this index can yield more accurate prediction of mid‐term responders and long‐term outcome after cardiac resynchronization therapy (CRT). Radial SDI for 75 CRT patients was calculated as the average difference between peak and end‐systolic speckle tracking strain from 6 segments of the mid‐LV short‐axis view before and 8 ± 2 days after CRT. Mid‐term responder was defined as ≥15% decrease in LV end‐systolic volume 6 ± 2 months after CRT. Long‐term outcome was tracked over 5 years. Baseline radial SDI ≥6.5% is considered predictive of responder and favorable outcome, as previously reported. Acute reduction in radial SDI ≥1.5% was found to be the best predictor of mid‐term responders with CRT. Furthermore, patients with acute reductions in radial SDI ≥1.5% were associated with a significantly more favorable long‐term outcome after CRT than those with radial SDI <1.5% (log rank P < 0.001). An important findings were that baseline radial SDI ≥6.5% and acute reductions in radial SDI ≥1.5% in 42 patients were associated with the highest event‐free survival rate of 92%, whereas, 21 patients corresponding values of <6.5% and <1.5% were associated with low event‐free survival rate of 46% (log rank P < 0.001). Combined assessment of baseline radial SDI and its acute reduction after CRT may have clinical implications for predicting responders and thus patients' care.