Assessment of the Right and Left Atrial Functions at Midterm After Surgical and Device Atrial Septal Defect Closure: A 2-Dimensional Speckle-Tracking Echocardiographic Study

OBJECTIVES

The available literature lacks data on the comparison of the functions of the right atrium (RA) and left atrium (LA) between surgical atrial septal defect (ASD) closure and percutaneous device ASD closure at follow-up durations of longer than 1 year. We sought to evaluate the RA and LA functions in patients who underwent surgical or device ASD closure between 1 and 5 years postprocedurally.

METHODS

The study population included 30 patients who underwent device ASD closure and 30 who underwent surgical ASD closure, who were matched for the procedural time, age, and sex, in addition to 30 control participants. The RA and LA functions were evaluated with 2-dimensional speckle-tracking echocardiography.

RESULTS

The LA systolic and early diastolic strain and strain rate values and the RA early diastolic strain rate in the device closure group were more likely to be abnormal than in the control group. The RA systolic and late diastolic strain and strain rate values, the RA early diastolic strain rate, and the LA early diastolic strain in the surgical closure group were more likely to be abnormal than in the control group. The RA systolic strain and strain rate in the surgical closure group were more likely to be abnormal than in the device closure group.

CONCLUSIONS

The LA reservoir and conduit functions and the RA contraction function in the patients who underwent device ASD closure and all of the RA functions and the LA conduit function in the patients who underwent surgical ASD closure were more likely to be abnormal than those in the control participants. The RA reservoir function in the surgical closure group was more likely to be abnormal than that in the device closure group.

Intergenerational differences in the effects of transcatheter closure of atrial septal defects on cardiac function

BACKGROUND

Little is known regarding intergenerational differences in the effects of atrial sepal defect (ASD) closure on the left heart. We therefore analyzed age-related serial changes in the left heart following ASD closure.

METHODS

We studied 50 patients with an isolated ASD who underwent successful transcatheter closure using Amplatzer septal occluders (St. Jude Medical, Little Canada, MN, USA) between June 2007 and June 2013. Patients were divided into three age groups: young patients aged ≤17 years; middle-aged patients aged 18-50 years; and older patients aged >50 years. Multi-modal echocardiographic studies with different views were performed before and at 1 day, 1-3 months, and 6-12 months after ASD closure. Echocardiographic variables were compared among the groups at different time points after closure.

RESULTS

Left ventricular end-diastolic and end-systolic volume indices (EDVI and ESVI) in the older group were significantly smaller than those in the other groups before closure. EDVI and ESVI increased with time after closure in all groups with stable ejection fractions. However, EDVI and ESVI remained significantly smaller in the older group compared with the other groups. There was a significant interaction among the age groups only in terms of left atrial volume index (LAVI). LAVI increased significantly with time in the older group, but did not change in the other groups.

CONCLUSION

Although the left ventricle enlarged with time after ASD closure in all age groups, left ventricular size in older patients never reached that in younger patients. In addition to this inadequate enlargement of the left ventricle, diastolic dysfunction might also result in late left atrial enlargement in older patients following ASD closure.

Ventricular structure, function, and mechanics at high altitude: chronic remodeling in Sherpa vs. short-term lowlander adaptation

Short-term, high-altitude (HA) exposure raises pulmonary artery systolic pressure (PASP) and decreases left-ventricular (LV) volumes. However, relatively little is known of the long-term cardiac consequences of prolonged exposure in Sherpa, a highly adapted HA population. To investigate short-term adaptation and potential long-term cardiac remodeling, we studied ventricular structure and function in Sherpa at 5,050 m (n = 11; 31 ± 13 yr; mass 68 ± 10 kg; height 169 ± 6 cm) and lowlanders at sea level (SL) and following 10 ± 3 days at 5,050 m (n = 9; 34 ± 7 yr; mass 82 ± 10 kg; height 177 ± 6 cm) using conventional and speckle-tracking echocardiography. At HA, PASP was higher in Sherpa and lowlanders compared with lowlanders at SL (both P < 0.05). Sherpa had smaller right-ventricular (RV) and LV stroke volumes than lowlanders at SL with lower RV systolic strain (P < 0.05) but similar LV systolic mechanics. In contrast to LV systolic mechanics, LV diastolic, untwisting velocity was significantly lower in Sherpa compared with lowlanders at both SL and HA. After partial acclimatization, lowlanders demonstrated no change in the RV end-diastolic area; however, both RV strain and LV end-diastolic volume were reduced. In conclusion, short-term hypoxia induced a reduction in RV systolic function that was also evident in Sherpa following chronic exposure. We propose that this was consequent to a persistently higher PASP. In contrast to the RV, remodeling of LV volumes and normalization of systolic mechanics indicate structural and functional adaptation to HA. However, altered LV diastolic relaxation after chronic hypoxic exposure may reflect differential remodeling of systolic and diastolic LV function.

Impact of the Amplatzer atrial septal occluder device on left ventricular function in pediatric patients

Percutaneous closure currently is widely considered to be the first-choice therapeutic option in the treatment of ostium secundum atrial septal defect (ASD). The Amplatzer Septal Occluder (ASO) device is the most used prosthesis, although its influence on cardiac function still is under active investigation. This study aimed to evaluate the impact of the ASO device size on left ventricular (LV) function in pediatric patients using the speckle-tracking strain imaging technology. The study enrolled 43 nonobese pediatric patients submitted to percutaneous ASD closure with the Amplatzer Septal Occluder device and grouped them according to the size of the occluding prosthesis into three groups: a small-device group (≤ 10 mm, group 1), a medium-size-device group (11-16 mm, group 2), and a large-device group (≥ 17 mm, group 3). Echocardiographic data were compared among the groups and with the data of an age-, weight-, and gender-matched control group (50 patients). The large-device group showed a significant impairment in the strain rate value of the basal LV segments. In particular, the mean basal circumferential and radial strain rate values were lower than either normal or the values of the small- and medium-device groups. However, only the absolute device diameter reached statistical significance in the multivariate analysis. The large Amplatzer Septal Occluding device significantly impaired LV systolic function, particularly that of juxtaprosthetic segments, as shown in the strain rate analysis.

Left ventricular torsion abnormalities in patients after the arterial switch operation for transposition of the great arteries with intact ventricular septum

BACKGROUND

The arterial switch operation (ASO) is currently the treatment of choice for infants with transposition of the great arteries (TGA). Little is known, however, about the alteration of anatomic left ventricular (LV) torsional mechanics after the operation. This study sought to evaluate LV torsion in patients of transposition of the great arteries with intact ventricular septum (TGA/IVS) using speckle tracking echocardiography.

METHODS

Echocardiographic images were prospectively acquired in 32 infants (age range, 0.5-60 months) who successfully underwent ASO repair at about 1 month of age and in 48 normal controls. They were divided into early and late categories according to the age at the time of the study. The LV peak systolic torsion and systolic twisting and diastolic untwisting velocities were determined by speckle tracking. Mitral inflow velocity obtained by Pulsed-wave Doppler and mitral annular velocities drawn by septal tissue Doppler were also analyzed.

RESULTS

Compared with controls, the early postoperative group (TGA1) had significantly higher septal E/e' (P=0.000). In contrast, septal e' velocity (P=0.000), LV peak apical rotation (P=0.01), twist (P=0.02) and peak untwisting velocity (PUV) (P=0.001) were lower in patients than in controls. For the normal younger group (Control1), PUV correlated positively with e' (r=0.68, P<0.001). No significant difference in LV twisting and untwisting was noted between the TGA2 and Control2.

CONCLUSIONS

Two dimensional speckle tracking echocardiography may sensitively detect impaired LV torsional mechanics in patients with TGA/IVS early after ASO, and the impairment of LV relaxation leads to increased LV filling pressure which is consistent with higher E/e'. However, all patients recovered well thereafter and the overall midterm outcome of ASO is satisfactory.

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.

Torsional mechanics of the left ventricle in patients after surgical repair of tetralogy of Fallot

BACKGROUND

This study aimed to test the hypothesis that alteration of left ventricular (LV) torsional mechanics occurs in patients after repair of tetralogy of Fallot (TOF) and is associated with right ventricular (RV) volume overload and changes in LV configuration.

METHODS AND RESULTS

Fifty-five TOF patients aged 19.0 ± 8.1 years and 27 age-matched healthy controls were studied. The LV and RV volumes were measured using 3-dimensional echocardiography while LV geometry was quantified by the diastolic eccentricity index (EI). The LV peak systolic torsion and systolic twisting and diastolic untwisting velocities were determined by speckle tracking. Compared with controls, patients had significantly greater RV end-systolic (P < 0.001) and diastolic (P < 0.001) volumes and LV diastolic EI (P < 0.001). In contrast, LV peak apical rotation (P < 0.001), systolic torsion (P = 0.004), systolic twisting velocity (P = 0.001), and diastolic untwisting velocity (P = 0.001) were lower in patients than in controls. For the whole cohort, RV EDV and LV diastolic EI correlated negatively with peak systolic torsion, systolic twisting velocity, and diastolic untwisting velocity (all P ≤ 0.001). Systolic torsion correlated strongly with diastolic untwisting velocity (r = 0.72, P < 0.001), while systolic twisting velocity correlated with LV ejection fraction (r = 0.3, P = 0.005).

CONCLUSIONS

LV torsional mechanics is impaired and is negatively related to RV volume overload and LV eccentricity in patients after TOF repair.

Assessment of myocardial mechanics using speckle tracking echocardiography: fundamentals and clinical applications

The authors summarize the recent developments in speckle-tracking echocardiography (STE), a relatively new technique that can be used in conjunction with two-dimensional or three-dimensional echocardiography for resolving the multidirectional components of left ventricular (LV) deformation. The tracking system is based on grayscale B-mode images and is obtained by automatic measurement of the distance between 2 pixels of an LV segment during the cardiac cycle, independent of the angle of insonation. The integration of STE with real-time cardiac ultrasound imaging overcomes some of the limitations of previous work in the field and has the potential to provide a unified framework to more accurately quantify the regional and global function of the left ventricle. STE holds promise to reduce interobserver and intraobserver variability in assessing regional LV function and to improve patient care while reducing health care costs through the early identification of subclinical disease. Following a brief overview of the approach, the authors pool the initial observations from clinical studies on the development, validation, merits, and limitations of STE.

Oblique 3D MRI tags for the estimation of true 3D cardiac motion parameters

Aim of this study is to demonstrate the advantages of oblique 3D tags in cardiac magnetic resonance imaging (MRI) and the potential to accurately describe the complex motion of the myocardial wall. 3D cardiac Cine data were densely tagged with 3D oblique tags. The latter were tracked using Gabor analysis and active geometries. From the tag intersections, common 2D parameters such as long axis shortening, radial shortening and rotation were evaluated on a global as well as detailed local level. Finally, the same data were used to estimate left ventricular volume change and myocardial stress/strain. We have successfully tracked dense 3D tags and evaluated common parameters on a detailed local level. In addition, inherently 3D parameters could be estimated. Global motion data are in accordance with previously published data. Oblique tags allow for unambiguous localization of the tag plane in all MRI slices and in any time frame. In contrast to HARP, our tag tracking methodology allows for tracking of the tags even when they are dense. Motion parameters can be extracted in greater detail. Moreover, the intersections of dense oblique 3D tags provide a natural basis for a finite element model of the heart. Straight forward access to the 3D characteristics of the cardiac motion is provided.