Effect of aging on twist-displacement loop by 2-dimensional speckle tracking imaging

Analysis of left ventricular rotational deformation by 2D speckle tracking echocardiography: a feasibility study in athletes

2D speckle tracking echocardiography (2DSTE) is established to analyse left ventricular (LV) longitudinal function. The analysis of LV rotational deformation is challenging and requires standardization of image acquisition as well as postprocessing analysis. The aim of this study was to test the feasibility to analyse LV rotational deformation using 2DSTE by introducing a novel algorithm for the detection of artefacts. The study was performed in 20 healthy subjects serving as a control group and in 53 competitive sportsmen. Circumferential, radial strain (CS, RS) and LV rotation were analysed by 2DSTE in parasternal short axis views. The stepwise algorithm to exclude potential artefacts starts with the visual estimation of the image quality with respect to complete visualization of all myocardial segments during the entire cardiac cycle followed by the exclusion of data sets in participants with conduction abnormalities. The next step is the optimization of tracking areas and a cross-check of implausible strain waveforms in multiple acquired comparable cineloops. The last step is the exclusion of strain curves with persisting implausible waveforms if standardization failures and incorrect LV wall tracking are fixed. Plausible physiological strain curves were observed in 89% (n = 65/73) of all subjects. In controls all implausible waveforms could be verified as artefacts. The algorithm was applied in 53 professional athletes to test and confirm its feasibility. Abnormal CS waveforms were documented in 25 athletes, verified as artefacts due to tracking failures in 22 athletes and due to incorrect image acquisition in 3 athletes. CS artefacts were mostly located in the basal posterior and lateral LV segments. (endocardial: 6%, n = 4/70; p < 0.05) and basal posterior (endocardial: 8%, n = 5/70; p < 0.05) segments were highly susceptible to artefacts. 2DSTE of parasternal short axis views to analyse circumferential and radial deformation as well as LV rotation is feasible in athletes. The proposed algorithm helps to avoid artefacts and might contribute to standardization of this technique. 2DSTE might provide an interesting diagnostic tool for the detection of viral myocarditis, e.g. in athletes.

Usefulness of Myocardial Strain and Twist for Early Detection of Myocardial Dysfunction in Patients With Autoimmune Diseases

Cardiac involvement in autoimmune diseases (AD) is common but underdiagnosed due to a lack of sensitive imaging methods. We aim to evaluate the characteristics of left ventricular (LV) systolic dysfunction in patients with AD using deformational parameters from 2-dimensional speckle-tracking echocardiography (STE). We retrospectively enrolled 86 AD patients and 71 healthy controls. All subjects underwent transthoracic echocardiography and STE to analyze LV strain and twist. A twist-radial displacement loop was constructed to investigate the relation between LV contractility and dimension. In AD patients, 68 had preserved LV ejection fraction (EF ≥ 50%), and 18 had reduced LVEF (EF < 50%). The patients with preserved LVEF exhibited significantly lower values of global longitudinal, circumferential, and radial strain than controls (-19.11 ± 4.18 vs -21.49 ± 2.53%, -25.17 ± 5.04% vs -27.37 ± 2.87%, 17.68 ± 5.69% vs 21.17 ± 6.44%, respectively; all p <0.01) and a marked attenuation in peak twist (14.24 ± 5.57 vs 18.10 ± 5.97, p <0.01) attributed to impaired apical rotation (9.03 ± 5.17 vs 12.79 ± 5.99, p <0.01). AD patients were more likely to present with abnormal loop types with flat ascending slope and delayed peak twist time. In conclusion, abnormal strain and twist precede deterioration in LVEF, suggesting early myocardial involvement in AD. STE can be used as a good alternative for early detection of myocardial dysfunction in AD patients.

Relation of arterial stiffness to left ventricular structure and function in healthy women

BACKGROUND

Interactions between the left ventricular (LV) and the arterial system, (ventricular-arterial coupling) are key determinants of cardiovascular function. However, most of studies covered multiple cardiovascular risk factors, which also contributed to the morphological and functional changes of LV. The aim of this study was to examine the relationship between arterial stiffness and LV structure and function in healthy women with a low burden of risk factors.

METHODS

Healthy women from the Twins UK cohort (n = 147, mean age was 54.07 ± 11.90 years) were studied. Arterial stiffness was evaluated by carotid-femoral pulse wave velocity (cf-PWV). LV structure and function were assessed by two-dimensional speckle tracking echocardiography.

RESULTS

cf-PWV was significantly associated with most measures of LV geometry and function, including relative wall thickness (RWT), E/e' ratio, global circumferential and radial strain, apical rotation and LV twist (each p <  0.05), but bore no relation to global longitudinal strain. After adjustment for age, body mass index, blood pressure and heart rate, cf-PWV was significantly correlated with RWT, global circumferential strain, apical rotation and LV twist (β = 0.011, - 0.484, 1.167 and 1.089, respectively, each p ≤  0.05).

CONCLUSIONS

In healthy women with a low burden of risk factors, elevated arterial stiffness was intimately interwoven with increased LV twisting even before LV dysfunction becomes clinically evident.

Left ventricular twist mechanics in the context of normal physiology and cardiovascular disease: a review of studies using speckle tracking echocardiography

The anatomy of the adult human left ventricle (LV) is the result of its complex interaction with its environment. From the fetal to the neonatal to the adult form, the human LV undergoes an anatomical transformation that finally results in the most complex of the four cardiac chambers. In its adult form, the human LV consists of two muscular helixes that surround the midventricular circumferential layer of muscle fibers. Contraction of these endocardial and epicardial helixes results in a twisting motion that is thought to minimize the transmural stress of the LV muscle. In the healthy myocardium, the LV twist response to stimuli that alter preload, afterload, or contractility has been described and is deemed relatively consistent and predictable. Conversely, the LV twist response in patient populations appears to be a little more variable and less predictable, yet it has revealed important insight into the effect of cardiovascular disease on LV mechanical function. This review discusses important methodological aspects of assessing LV twist and evaluates the LV twist responses to the main physiological and pathophysiological states. It is concluded that correct assessment of LV twist mechanics holds significant potential to advance our understanding of LV function in human health and cardiovascular disease.

Exercise Training Normalizes Timing of Left Ventricular Untwist Rate, but Not Peak Untwist Rate, in Individuals with Type 2 Diabetes and Diastolic Dysfunction: A Pilot Study

BACKGROUND

There is limited information regarding the role of left ventricular (LV) twist and the effect of exercise in type 2 diabetes (T2D). The aim of this study was to compare LV twist parameters in patients with T2D versus healthy control subjects and the effects of high-intensity interval exercise (HIIE) and moderate-intensity exercise (MIE) on LV twist in patients with T2D with diastolic dysfunction.

METHODS

This study, which included both prospective and retrospective components, included 47 patients with T2D and diastolic dysfunction and 37 healthy individuals. Patients with T2D were randomized to HIIE (4 × 4 min at 90%-95% of maximal heart rate, three times a week, 120 min/wk; n = 24) or MIE (210 min/wk; n = 23) for 12 weeks and examined with echocardiography (LV twist by speckle-tracking method) at baseline and posttest. The control subjects received no intervention and were matched according to age, gender, and body mass index to those completing the intervention.

RESULTS

In total, 37 subjects completed 12 weeks of MIE (n = 17) or HIIE (n = 20). LV peak untwist rate (UTR) was similar in patients with T2D and control subjects (P ˃ .05). At baseline, LV peak UTR, relative to total diastolic period, occurred 5.8 percentage points later in patients with T2D compared with control subjects (P = .004). Time to peak UTR was shortened by 6.5 percentage points (P = .002) and 7.7 percentage points (P < .001) after MIE and HIIE, respectively. Time to peak UTR was similar to that in control subjects after exercise interventions.

CONCLUSIONS

In patients with T2D and diastolic dysfunction, LV peak UTR was similar, but time to peak LV UTR was delayed compared with control subjects. Twelve weeks of endurance exercise normalized the timing of UTR.

Left ventricular atrioventricular plane displacement is preserved with lifelong endurance training and is the main determinant of maximal cardiac output

Age-related decline in cardiac function can be prevented or postponed by lifelong endurance training. However, effects of normal ageing as well as of lifelong endurance exercise on longitudinal and radial contribution to stroke volume are unknown. The aim of this study was to determine resting longitudinal and radial pumping in elderly athletes, sedentary elderly and young sedentary subjects. Furthermore, we aimed to investigate determinants of maximal cardiac output in elderly. Eight elderly athletes (63 ± 4 years), seven elderly sedentary (66 ± 4 years) and ten young sedentary subjects (29 ± 4 years) underwent cardiac magnetic resonance imaging. All subjects underwent maximal exercise testing and for elderly subjects maximal cardiac output during cycling was determined using a dye dilution technique. Longitudinal and radial contribution to stroke volume did not differ between groups (longitudinal left ventricle (LV) 52-65%, P = 0.12, right ventricle (RV) 77-87%, P = 0.16, radial 7.9-8.6%, P = 1.0). Left ventricular atrioventricular plane displacement (LVAVPD) was higher in elderly athletes and young sedentary compared with elderly sedentary subjects (14 ± 3, 15 ± 2 and 11 ± 1 mm, respectively, P < 0.05). There was no difference between groups for RVAVPD (P = 0.2). LVAVPD was an independent predictor of maximal cardiac output (R(2) = 0.61, P < 0.01, β = 0.78). Longitudinal and radial contributions to stroke volume did not differ between groups. However, how longitudinal pumping was achieved differed; elderly athletes and young sedentary subjects showed similar AVPD whereas this was significantly lower in elderly sedentary subjects. Elderly sedentary subjects achieved longitudinal pumping through increased short-axis area of the ventricle. Large AVPD was a determinant of maximal cardiac output and exercise capacity.

Role of left ventricular twist mechanics in cardiomyopathies, dance of the helices

Left ventricular twist is an essential part of left ventricular function. Nevertheless, knowledge is limited in “the cardiology community” as it comes to twist mechanics. Fortunately the development of speckle tracking echocardiography, allowing accurate, reproducible and rapid bedside assessment of left ventricular twist, has boosted the interest in this important mechanical aspect of left ventricular deformation. Although the fundamental physiological role of left ventricular twist is undisputable, the clinical relevance of assessment of left ventricular twist in cardiomyopathies still needs to be established. The fact remains; analysis of left ventricular twist mechanics has already provided substantial pathophysiological understanding on a comprehensive variety of cardiomyopathies. It has become clear that increased left ventricular twist in for example hypertrophic cardiomyopathy may be an early sign of subendocardial (microvascular) dysfunction. Furthermore, decreased left ventricular twist may be caused by left ventricular dilatation or an extensive myocardial scar. Finally, the detection of left ventricular rigid body rotation in noncompaction cardiomyopathy may provide an indispensible method to objectively confirm this difficult diagnosis. All this endorses the value of left ventricular twist in the field of cardiomyopathies and may further encourage the implementation of left ventricular twist parameters in the “diagnostic toolbox” for cardiomyopathies.

Left ventricular rotational mechanics before and after exercise in children

BACKGROUND

In children, there is limited information regarding the relative contribution of left ventricular (LV) apical and basal rotation to increase LV pump function with exercise. The aim of this study was to test the hypothesis that a progressive increase in LV pump function with exercise is related to increased LV apical and basal rotation.

METHODS

Forty-two subjects 12 to 18 years of age with normal cardiac structure and function were recruited prospectively and imaged at rest, and in 20 subjects, imaging was repeated after moderate exercise. Conventional measures of LV systolic and diastolic performance were evaluated. Left ventricular rotation, LV twist, rotational rate, and recoil and untwist rates were measured using two-dimensional speckle-tracking echocardiography. Torsion was calculated by normalizing LV twist to LV diastolic length. Twist displacement loops were constructed from data obtained at rest and after exercise.

RESULTS

Apical rotation increased significantly after exercise (7.33 ± 2.8° vs 11.6 ± 4.7°, P = .0004), but basal rotation did not (-4.85 ± 1.9 vs -6.46 ± 4.81, P = .21). Similarly, peak twist, torsion, and twist rate also increased significantly after exercise. In diastole, apical recoil rate and LV untwist rate also increased significantly with exercise. The slope of the systolic limb of the twist displacement loop and the area enclosed by the loop also increased significantly with exercise.

CONCLUSIONS

Increases in global LV pump function during exercise in children are associated with enhanced LV apical rotation but not LV basal rotation. In addition, unique changes were seen in twist displacement loops in children before and after exercise. These data may serve as a foundation for understanding future applications of LV rotational mechanics in disease states.

Kinetics of left ventricular rotation during exercise and its relation to exercise tolerance in atrial fibrillation: assessment by two-dimensional speckle tracking echocardiography

BACKGROUND

Left ventricular (LV) rotation plays an important role in cardiac function both at rest and during exercise in sinus rhythm. The kinetics of rotation during exercise and the relation between exercise tolerance and rotation-related parameters in patients with atrial fibrillation (AF) are unknown.

METHODS

Twenty-nine patients (age 62 ± 13 years, 6 females) with AF and preserved LV ejection fraction (LVEF) were studied using two-dimensional speckle tracking echocardiography at rest and during exercise with a supine bicycle ergometer (20 W, 10 min). We measured the systolic rotation (Rot) and the peak rotation rate in systole and early diastole (eRotR) at the apical and basal levels of the LV. All patients underwent cardiopulmonary exercise testing to obtain their percent achieved of the predicted peak oxygen consumption (% peak VO2) value.

RESULTS

During exercise, apical Rot-related indices were significantly increased only in the preserved % peak VO2 group. In contrast, E/e' was significantly elevated only in the reduced % peak VO2 group. Multivariable stepwise regression analysis showed that apical ΔRot was independently associated with % peak VO2 (β = 0.72; p < 0.01). Apical ΔeRotR, which could not be selected as an independent predictor of % peak VO2, had a good linear correlation with apical ΔRot (r = 0.81, p < 0.01).

CONCLUSIONS

The augmentation of apical rotation in response to exercise may coincide with an increase of the apical derotation rate, and apical rotation reserve may reflect exercise tolerance in patients with AF and preserved LVEF.

Age and the effectiveness of anti-hypertensive therapy on improvement in diastolic function

OBJECTIVE

Diastolic dysfunction is associated with adverse outcomes and is highly prevalent among older adults with hypertension. Lowering SBP with antihypertensive therapy has been shown to improve diastolic function, but whether or not age influences this effect is unknown.

METHODS

In the Exforge Intensive Control of Hypertension to Evaluate Efficacy in Diastolic Dysfunction trial, 189 patients (age range 45-93 years) with hypertension and diastolic dysfunction underwent echocardiography before and after 24 weeks of intensive versus standard antihypertensive therapy titrated to a goal SBP below 135 versus below 140  mmHg. We performed linear regression analyses to examine the association between age and improvement in diastolic function achieved with SBP reduction.

RESULTS

Antihypertensive therapy reduced SBP by 28 ± 19  mmHg overall, and this was not significantly different across age strata. However, percentage improvement in diastolic relaxation velocity (lateral E' peak velocity) for every 10  mmHg reduction in SBP was lower in older compared to younger patients. In analyses adjusting for age stratum, sex, treatment arm, baseline relaxation velocity, and baseline blood pressure, older age was associated with reduced improvement in diastolic relaxation velocity per 10  mmHg of SBP reduction (β -1.64, P = 0.009). In contrast, the degree of change in left ventricular mass index per 10  mmHg reduction in SBP was not influenced by age (P = 0.89).

CONCLUSIONS

In our sample of individuals with hypertension and diastolic dysfunction, older compared to younger adults experienced less improvement in diastolic function in response to similar reductions in SBP.

Normal values of regional and global myocardial wall motion in young and elderly individuals using navigator gated tissue phase mapping

The purpose of this study was to evaluate normal values for regional and global myocardial wall motion parameters in young and elderly individuals, as detected by navigator gated high temporal resolution tissue phase mapping. Radial, longitudinal and circumferential ventricular wall motion, as well as ventricular torsion and longitudinal strain rates, were assessed in two age groups of volunteers, 23 ± 3 (n = 14) and 66 ± 7 years old (n = 9), respectively. All subjects were healthy, non-smokers without known cardiac disease. An increased global left ventricular (LV) torsion rate (peak systolic torsion rate 20.6 ± 2.0 versus 14.5 ± 1.0°/s/cm, peak diastolic torsion rate -25.2 ± 1.8 versus -14.1 ± 1.3°/s/cm) and a decrease in longitudinal LV motion (peak systolic values at mid-ventricle 5.9 ± 0.5 versus 8.5 ± 0.8 cm/s, peak diastolic values -10.7 ± 0.7 versus -15.2 ± 0.9 cm/s) in the older age group were the most prominent findings. Lower peak diastolic radial velocities with a longer time-to-peak values, most pronounced at the apex, are consistent with reduced diastolic function with ageing. Lower peak clockwise and counter-clockwise velocities at all LV levels revealed limitations in resting LV rotational motions in the older group. Significant changes in the undulating pattern of the rotational motions of the left ventricle were also observed. The results demonstrate distinct changes in regional and global myocardial wall motion in elderly individuals. Increased LV torsion rate and reduced LV longitudinal motion were particularly prominent in the older group. These parameters may have a role in the assessment of global LV contractility and help differentiate age-related changes from cardiac disease.

Left ventricular torsion abnormalities in septic shock and corrective effect of volume loading: a pilot study

BACKGROUND

Ventricular torsion is an important component of cardiac function. The effect of septic shock on left ventricular torsion is not known. Because torsion is influenced by changes in preload, we compared the effect of fluid loading on left ventricular torsion in septic shock with the response in matched healthy control subjects.

METHODS

We assessed left ventricular torsion parameters using transthoracic echocardiography in 11 patients during early septic shock and in 11 age- and sex-matched healthy volunteers before and after rapid volume loading with 250 mL of a Ringer's lactate solution.

RESULTS

Peak torsion and peak apical rotation were reduced in septic shock (10.2 ± 5.2° and 5.6 ± 5.4°) compared with healthy volunteers (16.3 ± 4.5° and 9.6 ± 1.5°; P = 0.009 and P = 0.006 respectively). Basal rotation was delayed and diastolic untwisting velocity reached its maximum later during diastole in septic shock patients than in healthy volunteers (104 ± 16% vs 111 ± 14% and 13 ± 5% vs 21 ± 10%; P = 0.03 and P = 0.034, respectively). Fluid challenge increased peak torsion in both groups (septic shock, 10.2 ± 5.3° vs 12.6 ± 3.9°; healthy volunteers, 16.3 ± 4.5° vs 18.1 ± 6°; P = 0.01). Fluid challenge increased left ventricular stroke volume in septic shock patients (P = 0.003).

CONCLUSIONS

Compared with healthy volunteers, left ventricular torsion is impaired in septic shock patients. Fluid loading attenuates torsion abnormalities in parallel with increasing stroke volume. Reduced torsional motion might constitute a relevant component of septic cardiomyopathy, a notion that merits further testing in larger populations.

Left ventricular adaptation to acute hypoxia: a speckle-tracking echocardiography study

BACKGROUND

Hypoxia depresses myocardial contractility in vitro but does not affect or may even improve indices of myocardial performance in vivo, possibly through associated changes in autonomic nervous system tone. The aim of this study was to explore the effects of hypoxic breathing on speckle-tracking echocardiographic indices of left ventricular function, with and without β1-adrenergic inhibition.

METHODS

Speckle-tracking echocardiography was performed in 21 healthy volunteers in normoxia and after 30 min of hypoxic breathing (fraction of inspired oxygen, 0.12). Measurements were also obtained after the administration of atropine in normoxia (n = 21) and after bisoprolol intake in normoxia (n = 6) and in hypoxia (n = 10).

RESULTS

Hypoxia increased heart rate (from 68 ± 11 to 74 ± 9 beats/min, P = .001), without changing mean blood pressure (P = NS), and decreased total peripheral resistance (P = .003). Myocardial deformation magnitude increased (circumferential strain, -19.6 ± 1.9% vs -21.2 ± 2.5%; radial strain, 19.2 ± 3.7% vs 22.6 ± 4.1%, P < .05; longitudinal and circumferential strain rate, -0.88 ± 0.11 vs -0.99 ± 0.15 sec(-1) and -1.03 ± 0.16 vs -1.18 ± 0.18 sec(-1), respectively, P < .05 for both; peak twist, 8.98 ± 3.2° vs 11.1 ± 2.9°, P < .05). Except for peak twist, these deformation parameters were correlated with total peripheral resistance (P < .05). Atropine increased only longitudinal strain rate magnitude (-0.88 ± 0.11 vs -0.97 ± 0.14 sec(-1), P < .05). The increased magnitude of myocardial deformation persisted in hypoxia under bisoprolol (P < .05). In normoxia, bisoprolol decreased heart rate (73 ± 10 vs 54 ± 7 beats/min, P = .0005), mean blood pressure (88 ± 7 vs 81 ± 4 mm Hg, P = .0027), without altering deformation.

CONCLUSIONS

Hypoxic breathing increases left ventricular deformation magnitude in normal subjects, and this effect may not be attributed to hypoxia-induced tachycardia or β1-adrenergic pathway changes but to hypoxia-induced systemic vasodilation.

Left ventricular myocardial performance in patients with dengue hemorrhagic fever and thrombocytopenia as assessed by two-dimensional speckle tracking echocardiography

OBJECTIVES

We obtained longitudinal, radial and circumferential strains in patients with dengue hemorrhagic fever (DhF) and thrombocytopenia using two-dimensional (2D) speckle tracking echocardiography to analyze left ventricular (LV) myocardial performance.

METHODS

In this prospective study, 2D echocardiographic images of the left ventricle in the four-, three- and two-chamber views and parasternal short-axis views at the basal, mid and apical levels were obtained in 40 subjects: 20 patients (23 ± 8 years, 12 male) with DhF and thrombocytopenia and 20 healthy controls (23 ± 5 years, 11 male). Of the 20 patients, imaging was performed again in 19 at discharge after a hospital stay of 8 ± 1 days. Longitudinal, circumferential and radial strains were quantified and compared in an 18-segment model using a novel speckle tracking system.

RESULTS

Left ventricular global ejection fraction was reduced in patients with DhF at presentation as compared with controls (51.25 ± 0.96% vs. 59.32 ± 1.26%; p = 0.032). Peak longitudinal strain in patients with DhF was significantly attenuated in the subendocardial region compared with normal controls (p < 0.001). A significant increase in circumferential strain for patients with DhF was evident only in the subepicardial region (p = 0.009). Patients with DhF showed significantly higher radial strain than controls (p < 0.001). On multivariate analysis, subendocardial longitudinal strain independently predicted the duration of hospital stay in patients with DhF.

CONCLUSION

Assessment of speckle tracking echocardiography-derived LV mechanics helps in understanding myocardial mechanics in patients with DhF and thrombocytopenia. Identification of reduced LV longitudinal strain helps in understanding the mechanism of reduced LV myocardial performance seen in patients with DhF.

Early impairment of left ventricular function in patients with systemic hypertension: new insights with 2-dimensional speckle tracking echocardiography

BACKGROUND

Two-dimensional strain imaging allows rapid and accurate analysis of regional left ventricular (LV) principal strains in the longitudinal, radial, and circumferential directions. The aim of this study was to assess the ability of subtle differences in LV principal strains to characterize features of subclinical LV dysfunction in patients with systemic hypertension and apparently preserved LV systolic function.

METHODS

2-dimensional echocardiographic (2DE) images of the LV were acquired in apical 4-chamber and parasternal short-axis at the basal, mid, and apical levels in 59 subjects, including 25 healthy controls (33 ± 4 yrs, 14 male) and 34 patients with systemic hypertension (36 ± 3 yrs, 24 male). Longitudinal (LS), circumferential (CS) and radial strains (RS) were quantified in an 18-segment model using a novel speckle tracking system (2D Cardiac Performance Analysis, TomTec Imaging System, Munich, Germany).

RESULTS

In comparison with normal controls, peak LS was markedly attenuated in the subendocardial and subepicardial regions in patients with systemic hypertension. However, circumferential strain was reduced only in subepicardial region; radial strain was not significantly different in the two groups. The subendocardial-to-subepicardial gradient of circumferential deformation correlated with the radial strains in both controls and hypertensive patients (R = 0.87, p < 0.001).

CONCLUSIONS

Despite reduced longitudinal shortening, LV wall thickening in patients with systemic hypertension remains unaltered due to relatively preserved circumferential shortening. Characterizing the disparities in LV principal strains reveals the presence of subclinical LV dysfunction and provides unique insights into functional adaptations that maintain global LV ejection fraction in patients with systemic hypertension.

Left ventricular twisting mechanics and exercise in healthy individuals: a systematic review

The aim of this study was to review systematically the effects of exercise on left ventricular (LV) twisting mechanics in healthy individuals. Literature searches were conducted in electronic databases for articles reporting measures of LV twisting mechanics in healthy individuals before and during/after exercise. Upon review, 18 articles were analyzed. Studies were separated by exercise type into the following four categories to allow for detailed comparisons: submaximal, prolonged endurance, maximal, and chronic endurance. Despite an overall methodological quality of low to moderate and within-group variations in exercise intensity, duration, and subject characteristics, important trends in the literature emerged. Most important, the coupling of LV systolic twisting and diastolic untwisting was present in all exercise types, as both were either improved or impaired concomitantly, highlighting the linkage between systole and diastole provided through LV twist. In addition, trends regarding the effects of age, training status, and cardiac loading also became apparent within different exercise types. Furthermore, a potential dose-response relationship between exercise duration and the degree of impairment to LV twisting mechanics was found. Although some disagreement existed in results, the observed trends provide important directions for future research. Future investigations should be of higher methodological quality and should include consistent exercise protocols and subject populations in order to minimize the variability between investigations.

Left ventricular myocardial performance assessed by 2-dimensional speckle tracking echocardiography in patients with sickle cell crisis

BACKGROUND

The status of left ventricle in sickle cell anemia presenting in sickle crisis and follow up has been minimally studied in past. To determine the left ventricular (LV) myocardial performance in these patients, we performed the study to assess two dimensional strains imaging which allowed a rapid and an accurate analysis of global and regional LV myocardial performance in longitudinal, radial, and circumferential directions.

METHODS

In this prospective study, 2-dimensional echocardiography (2DE) images of the LV were obtained in 52 subjects which included 32 patients (23 ± 8yrs, 16 male) with homozygous sickle cell anemia (SCA) in sickle cell crisis and 20 healthy controls (23 ± 5 yrs, 11 male) using apical 4-chamber and parasternal short-axis at the basal, mid, and apical levels. Of these 32 patients, 2DE was performed again in 18 patients in follow up (8 months ± 5 days). Longitudinal, circumferential and radial strains (LS, CS and RS respectively) were quantified and compared in an 18-segment model using a novel speckle tracking system (2D Cardiac Performance Analysis, TomTec Imaging System, Munich, Germany).

RESULTS

There was no significant difference in LV ejection fraction between both the groups (59.32 ± 12.6 vs. 52.3 ± 7.9; p-value > 0.05). In comparison with normal controls and follow up of sickle cell patients, peak LS was significantly attenuated in the subendocardial and subepicardial regions during sickle cell crisis (p < 0.05). However, a significant reduction in circumferential strain was evident only in subepicardial region (p < 0.001). Also patients in sickle cell crisis showed significantly higher radial strain parameters than controls (p < 0.001).

CONCLUSION

Patients with SCA presenting in sickle cell crisis have reduced longitudinal shortening. LV myocardial performance remains unaltered due to relatively preserved circumferential shortening and increased radial thickening.

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 (PtwN), 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.

Evaluation of left ventricular rotation by two-dimensional speckle tracking method and real-time three-dimensional echocardiography: comparison with MRI tagging method

BACKGROUND

Recently, it has become possible to evaluate left ventricular (LV) torsion by two-dimensional (2D) speckle tracking images. However, LV torsion is a three-dimensional (3D) performance, which per se cannot be assessed by the 2D speckle tracking method. The present study investigated the accuracy of the 2D speckle tracking method and real-time 3D echocardiography in measuring LV rotation, comparing with the MRI tagging method.

METHODS

We assessed LV apical rotation using the 2D speckle tracking method, real-time 3D echocardiography, and MRI tagging method in 26 normal subjects, and compared the results of these three methods. LV apical rotation was measured just before the level in which the posterior papillary muscle was absorbed into the free wall.

RESULTS

The degree of LV apical rotation evaluated by the 2D speckle tracking method (Δθ 2D) was significantly smaller than that evaluated by 3D echocardiography (Δθ 3D) and the MRI tagging method (Δθ MRI) (Δθ 2D 7.3 ± 2.8°; Δθ 3D 8.8 ± 3.4°; Δθ MRI 9.0 ± 3.4°; Δθ 2D vs. Δθ 3D, p = 0.0001; Δθ 2D vs. Δθ MRI, p < 0.0001). There were good correlations among Δθ 2D, Δθ 3D, and Δθ MRI, but agreement between Δθ 3D and Δθ MRI (mean difference 0.14 ± 1.43°) was better than that between Δθ 2D and Δθ MRI (mean difference 1.68 ± 1.89°).

CONCLUSION

The degree of LV apical rotation was underestimated with the 2D speckle tracking method compared with the MRI tagging method, whereas it could be precisely measured by 3D echocardiography.

Left ventricular torsion parameters are affected by acute changes in load

BACKGROUND

Quantification of left ventricular torsion may provide new indices of systolic and diastolic function. We sought to characterize the effect of acute manipulation of load on cardiac torsion, plecotropy in human subjects.

METHODS

Simultaneous Millar LV pressure, micromanometry, and echocardiograms were performed on 18 patients (10 male, mean age 66 years) with normal systolic function. Loading was altered sequentially by the administration of glyceryl trinitrate (GTN) and saline fluid loading. Echocardiographic speckle tracking imaging was used to quantify LV torsion and event timing was recorded relative to mitral valve opening (MVO).

RESULTS

GTN administration decreased preload (LV end diastolic pressure: 15.7 vs 8.4 mmHg, P < 0.001), and afterload (wall stress: 140 vs 84 x10(3)dyn/cm(2), P < 0.02). Administration of fluid increased preload (LVEDP 11.3 vs 18.1 mmHg, P < 0.001) and increased wall stress, but to a lesser extent (102 vs 117 x10(3)dyn/cm(2), P < 0.003). GTN administration augmented peak torsion (8.4 vs 11.0 deg, P < 0.05), increased systolic torsion velocity (46.6 vs 65.3deg/sec, P < 0.01) and resulted in earlier onset of untwisting (-105 vs -127ms, P < 0.05). Fluid loading decreased the proportion of untwisting prior to MVO (39.0 vs 31.0%, P < 0.05), untwisting acceleration (-750 vs -592deg/sec/sec, P < 0.05) and delayed the timing of peak untwisting (-37.0 vs 9.1ms, P < 0.01), but did not affect systolic torsion parameters.

CONCLUSIONS

Left ventricular torsion parameters are sensitive to acute changes in load and therefore need to be interpreted in the context of current loading conditions.

Influence of cardiac shape on left ventricular twist

The dynamic interaction between subendocardial and subepicardial fibre helices in the left ventricle (LV) leads to a twisting deformation, which has an important role in LV function. This study sought to assess the influence of cardiac shape on LV twist in the normal and dilated human heart. The study comprised 45 dilated cardiomyopathy (DCM) patients and 60 for age- and gender-matched healthy volunteers. Speckle tracking echocardiography was used to determine basal and apical LV peak systolic rotation (Rotmax) and instantaneous LV peak systolic twist (Twistmax). LV sphericity index was calculated by dividing the LV maximal long-axis internal dimension by the maximal short-axis internal dimension at end-diastole. A parabolic relation between the sphericity index and apical Rotmaxor Twistmaxwas identified in the total study population ( R2= 0.56 and R2= 0.54, respectively; both P < 0.001) and healthy volunteers ( R2= 0.39 and R2= 0.25, respectively; both P < 0.001), whereas these relations were linear in DCM patients ( R2= 0.40 and R2= 0.43, respectively; both P < 0.001). In a multivariate analysis, LV sphericity index was the strongest independent predictor of apical Rotmaxand Twistmax. In conclusion, LV apical rotation and twist are significantly influenced by LV configuration. Taking the important function of LV twist into account, this finding highlights the vital influence of cardiac shape on LV systolic function.

Alterations in left ventricular untwisting with ageing

BACKGROUND

In order to gain further insight into age-associated changes of left ventricular (LV) diastolic function, the purpose of the current study was to investigate alterations in LV untwisting with ageing.

METHODS AND RESULTS

The study comprised 75 healthy volunteers, classified into 3 groups: age 16-35 (n=25), 36-55 (n=25) and 56-75 (n=25) years. LV untwisting (as a percentage of peak systolic twist) at 5%, 10%, 15% and 50% of diastole, peak diastolic untwisting velocity, time-to-peak diastolic untwisting velocity and untwisting rate (mean untwisting velocity during the time interval from peak systolic twist to mitral valve opening) were assessed using speckle-tracking echocardiography. Untwisting at 5%, 10%, 15% and 50% of diastole decreased with ageing. Although the peak diastolic untwisting velocity and untwisting rate were not significantly different between the age groups, when normalized for LV peak systolic twist, these parameters decreased with advancing age (both P<0.01). Time-to-peak diastolic untwisting velocity increased with ageing (P<0.01).

CONCLUSIONS

Impairment of the relative peak diastolic untwisting velocity and untwisting rate, resulting in delayed LV untwisting, may help to explain diastolic dysfunction in the elderly. (Circ J 2010; 74: 101 - 108).

The pathophysiology of heart failure with normal ejection fraction: exercise echocardiography reveals complex abnormalities of both systolic and diastolic ventricular function involving torsion, untwist, and longitudinal motion

OBJECTIVES

The purpose of this study was to test the hypothesis that in heart failure with normal ejection fraction (HFNEF) exercise limitation is due to combined systolic and diastolic abnormalities, particularly involving ventricular twist and deformation (strain) leading to reduced ventricular suction, delayed untwisting, and impaired early diastolic filling.

BACKGROUND

A substantial proportion of patients with heart failure have a normal left ventricular ejection fraction. Currently the pathophysiology is considered to be due to abnormal myocardial stiffness and relaxation.

METHODS

Patients with a diagnosis of HFNEF and proven cardiac limitation by cardiopulmonary exercise testing were studied by standard, tissue Doppler, and speckle tracking echocardiography at rest and on submaximal exercise.

RESULTS

Fifty-six patients (39 women; mean age 72 +/- 7 years) with a clinical diagnosis of HFNEF and 27 age-matched healthy control subjects (19 women; mean age 70 +/- 7 years) had rest and exercise images of sufficient quality for analysis. At rest, systolic longitudinal and radial strain, systolic mitral annular velocities, and apical rotation were lower in patients, and all failed to rise normally on exercise. Systolic longitudinal functional reserve was also significantly lower in patients (p < 0.001). In diastole, patients had reduced and delayed untwisting, reduced left ventricular suction at rest and on exercise, and higher end-diastolic pressures. Mitral annular systolic and diastolic velocities, systolic left ventricular rotation, and early diastolic untwist on exercise correlated with peak VO(2)max.

CONCLUSIONS

In HFNEF there are widespread abnormalities of both systolic and diastolic function that become more apparent on exercise. HFNEF is not an isolated disorder of diastole.

Feasibility and reproducibility of left ventricular rotation parameters measured by speckle tracking echocardiography

AIMS

This study sought to find the most robust method for left ventricular (LV) rotation measurement by speckle tracking echocardiography (STE) with the new QLAB Advanced Quantification Software (version 6.0, Philips, Best, The Netherlands).

METHODS AND RESULTS

The study population consisted of 40 non-selected patients (mean age 48 +/- 18 year, 20 men) and 50 non-selected healthy volunteers (mean age 34 +/- 12 year, 21 men). Feasibility and intra-observer reproducibility of the measurement of LV rotation parameters by STE were assessed for two different methods (Method A: six tracking points placed mid-myocardial and Method B: six tracking points placed endocardial and epicardial forming six myocardial segments). Subsequently, inter-observer and temporal reproducibility of the most robust method were assessed. Complete LV rotation assessment was more feasible with Method A (60 out of 90 subjects, 67% vs. 50 out of 90 subjects, 56%). In the 49 subjects in whom both Methods A and B were feasible, intra-observer reproducibility of LV rotation parameters was better with Method A (variabilities 2 +/- 3 to 10 +/- 9% vs. 2 +/- 4 to 21 +/- 18%). With this method, inter-observer variability varied from 4 +/- 4 to 13 +/- 9% and temporal variability from 4 +/- 6 to 19 +/- 15%.

CONCLUSION

The most robust method to assess LV rotation with QLAB software is from the mid-myocardium. This method is feasible in approximately two-thirds of subjects and has good intra-observer, inter-observer, and temporal reproducibility, allowing to study changes over time in LV rotation in an individual patient.

Age-related changes in the biomechanics of left ventricular twist measured by speckle tracking echocardiography

The increasing number and proportion of aged individuals in the population warrants knowledge of normal physiological changes of left ventricular (LV) biomechanics with advancing age. LV twist describes the instantaneous circumferential motion of the apex with respect to the base of the heart and has an important role in LV ejection and filling. This study sought to investigate the biomechanics behind age-related changes in LV twist by determining a broad spectrum of LV rotation parameters in different age groups, using speckle tracking echocardiography (STE). The final study population consisted of 61 healthy volunteers (16–35 yr, n = 25; 36–55 yr, n = 23; 56–75 yr, n = 13; 31 men). LV peak systolic rotation during the isovolumic contraction phase (Rotearly), LV peak systolic rotation during ejection (Rotmax), instantaneous LV peak systolic twist (Twistmax), the time to Rotearly, Rotmax, and Twistmax, and rotational deformation delay (defined as the difference of time to basal Rotmax and apical Rotmax) were determined by STE using QLAB Advanced Quantification Software (version 6.0; Philips, Best, The Netherlands). With increasing age, apical Rotmax ( P < 0.05), time to apical Rotmax ( P < 0.01), and Twistmax ( P < 0.01) increased, whereas basal Rotearly ( P < 0.001), time to basal Rotearly ( P < 0.01), and rotational deformation delay ( P < 0.05) decreased. Rotational deformation delay was significantly correlated to Twistmax ( R2 = 0.20, P < 0.05). In conclusion, Twistmax increased with aging, resulting from both increased apical Rotmax and decreased rotational deformation delay between the apex and the base of the LV. This may explain the preservation of LV ejection fraction in the elderly.

Alteration in left ventricular normal and shear strains evaluated by 2D-strain echocardiography in the athlete's heart

The contraction of cardiomyocytes induces a systolic increase in left ventricular (LV) normal (radial, circumferential and longitudinal) and shear strains, whose functional consequences have not been evaluated, so far, in athletes. We used 2D ultrasound speckle tracking imaging (STI) to evaluate LV regional strain in high-level cyclists compared to sedentary controls. Sixteen male elite cyclists and 23 sedentary controls underwent conventional, tissue Doppler, and STI echocardiography at rest. We assessed LV long and short axis normal strains and shear strains. We evaluated circumferential-longitudinal shear strain from LV torsion, and circumferential-radial shear strain from the difference between subendocardial and subepicardial torsion. Apical radial strain (42.7 +/- 10.5% versus 52.2 +/- 14.3%, P < 0.05) and LV torsion (6.0 +/- 1.8 deg versus 9.2 +/- 3.2 deg, P < 0.01) were lower in cyclists than in controls, respectively. Rotations and torsion were higher in the subendocardial than in the subepicardial region in sedentary controls, but not in cyclists. Haemodynamic and tissue Doppler based indexes of global LV diastolic and systolic functions were not different between cyclists and controls. Athlete's heart is associated with specific LV adaptation including lower apical strain and lower myocardial shear strains, with no change in global LV diastolic and systolic function. These mechanical alterations could improve the cardiovascular adjustments to exercise by increasing the radial strain and torsional (and thus untwisting) response to exercise, a key element of diastolic filling and thus of cardiac performance in athletes.