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)     

超声心动图评价肺动脉高压患者右室功能的研究进展

肺动脉高压的发展会导致患者右室功能减低,对肺动脉高压患者右室功能的评价对其预后具有十分重要的临床意义。随着超声技术的不断发展,特别是新型超声技术的出现能敏感、准确地定量反映肺动脉高压患者的右室功能。现就目前超声心动图技术在评价肺动脉高压患者右室功能中的应用做一综述。     

肺动脉高压患者右室功能的多普勒超声评价与进展

肺动脉高压会导致患者右室功能减低,早诊断、早治疗肺动脉高压能明显改善患者的预后。近年来应用多普勒超声技术对肺动脉高压患者右室功能研究的新进展层出不穷,如双多普勒同步技术、Tei指数及三尖瓣环收缩期位移等,均为临床提供了全新的评价肺动脉高压及右室功能的新手段及新参数。     

Contractile Dysfunction of Left Ventricular Cardiomyocytes in Patients With Pulmonary Arterial Hypertension

Background

After lung transplantation, increased left ventricular (LV) filling can lead to LV failure, increasing the risk of post-operative complications and mortality. LV dysfunction in pulmonary arterial hypertension (PAH) is characterized by a reduced LV ejection fraction and impaired diastolic function.

Objectives

The pathophysiology of LV dysfunction in PAH is incompletely understood. This study sought to assess the contribution of atrophy and contractility of cardiomyocytes to LV dysfunction in PAH patients.

Methods

LV function was assessed by cardiac magnetic resonance imaging. In addition, LV biopsies were obtained in 9 PAH patients and 10 donors. The cross-sectional area (CSA) and force-generating capacity of isolated single cardiomyocytes was investigated.

Results

Magnetic resonance imaging analysis revealed a significant reduction in LV ejection fraction in PAH patients, indicating a reduction in LV contractility. The CSA of LV cardiomyocytes of PAH patients was significantly reduced (∼30%), indicating LV cardiomyocyte atrophy. The maximal force-generating capacity, normalized to cardiomyocyte CSA, was significantly reduced (∼25%). Also, a reduction in the number of available myosin-based cross-bridges was found to cause the contractile weakness of cardiomyocytes. This finding was supported by protein analyses, which showed an ∼30% reduction in the myosin/actin ratio in cardiomyocytes from PAH patients. Finally, the phosphorylation level of sarcomeric proteins was reduced in PAH patients, which was accompanied by increased calcium sensitivity of force generation.

Conclusions

The contractile function and the CSA of LV cardiomyocytes is substantially reduced in PAH patients. We propose that these changes contribute to the reduced in vivo contractility of the LV in PAH patients.     

The Role of Echocardiography in the Evaluation of Pulmonary Arterial Hypertension

The evaluation of pulmonary arterial hypertension (PAH) requires a multimodality approach that combines invasive and noninvasive imaging studies to ensure accurate diagnosis and classification. Given the complexity of the hemodynamic relationships between the left heart, pulmonary circulation, and right heart, the diagnosis of PAH is often a challenging task. Right heart catheterization is the gold standard for diagnosis, providing the hemodynamic information that defines the disease. Nonetheless, echocardiography continues to be a valuable tool in the approach to the patient with suspected PAH. Echocardiographic assessment generates a wealth of information about the response of the right heart to elevated pulmonary pressures and provides essential diagnostic and prognostic data to the clinician. Numerous measurements can be used to identify alterations in right heart morphology, pressure, and function; although each variable in isolation may have little utility, meaningful information is revealed when multiple parameters are considered together. In this article, we will review the echocardiographic measurements employed in assessment of the right heart and seek to clarify the role of echocardiography in the diagnostic workup of PAH.     

Left Ventricular Strain Examination of Different Aged Adults with 3D Speckle Tracking Echocardiography

The purpose of this study was to identify traits of the left ventricular (LV) global longitudinal strain (GLS), global radial strain (GRS), global circular strain (GCS), and global area tracking (GAT) with three‐dimensional speckle tracking echocardiography (3DSTE), and to determine the relationship between strain and age in healthy adults of different ages. A total of 153 volunteers were divided into young adult, middle‐aged, and elderly groups, and examined with echocardiography to obtain general data and live two‐dimensional (2D) images of the apical four‐chamber view, which were assembled to obtain the full volume view of the LV. The images were then analyzed with 3DSTE software. Compared with the young adult and middle‐aged groups, elderly adults demonstrated lower GLS, GRS, GCS, and GAT. Significant differences were not noted in GLS, GRS, and GCS between the young adult and middle‐aged groups; however, the GAT of the middle‐aged group was lower than that of the young adult group. The longitudinal strain (LS), radial strain (RS), and area tracking (AT) of 16 LV segments of the young adult group decreased gradually in level from the mitral valve to the apex, and increased in circular strain (CS). The LS, RS, CS, and AT of the middle‐aged group also decreased gradually. The LS, RS, CS, and AT of the elderly people were highest from the mitral valve to the apex level and lowest at the papillary muscle. The results of this study demonstrated that LV GLS, GRS, GCS, and GAT decrease with age.     

The Impact of Mitral Stenosis on Left Atrial Function Assessed by Two‐Dimensional Speckle Tracking Echocardiography

Aims: The aim of this study is to investigate the effect of mitral stenosis (MS) on left atrial (LA) function using two‐dimensional speckle tracking echocardiography (2DSTE). Methods and Results: The study subjects consisted of 52 patients with asymptomatic MS and 52 control subjects. LA function was assessed using prototype speckle tracking software and manual tracking method. Maximal LA volume (LAVmax) and minimal LA volume (LAVmin) and LA volume before atrial contraction (LAVpre‐a) were measured. Using these volumes, LA reservoir, conduit and booster pump fuction parameters were calculated. Indexed LAVmax, LAVmin, and LAVpre‐a measurements via speckle tracking were highly correlated with manual tracing methods in both groups. Expansion index (67.8 ± 36.4 vs. 148.3 ± 44.2), diastolic emptying index (37.7 ± 12.9 vs. 58.0 ± 8.5), passive emptying (37.3 ± 14.1 vs. 70.4 ± 10.4) and passive emptying index (13.3 ± 6.3 vs. 41.3 ± 10.6) were decreased significantly in MS patients (P < 0.001). In contrast active emptying index (62.6 ± 4.1 vs. 29.5 ± 10.1) increased in MS group (P < 0.001) while active emptying (28.1 ± 13.0 vs. 28.3 ± 6.9) remained same among both groups. Conclusions: This is the first study relating LA volumes and function assessed by 2DSTE to MS. 2D speckle tracking analysis of LA volume is relatively easy and provides more detailed information regarding the changes in LA volumes during the cardiac cycle.