Left Ventricular Untwist Rate Research Articles

Echocardiographic evidence of left ventricular untwisting-filling interplay

BackgroundLeft ventricular untwisting generates an early diastolic intraventricular pressure gradient (DIVPG) than can be quantified by echocardiography. We sought to confirm the quantitative relationship between peak untwisting rate and peak DIVPG in a large adult population.MethodsFrom our echocardiographic database, we retrieved all the echocardiograms with a normal left ventricular ejection fraction, for whom color Doppler M-Mode interrogation of mitral inflow was available, and left ventricular untwisting rate was measurable using speckle tracking. Standard indices of left ventricular early diastolic function were assessed by Doppler (peaks E, e’ and Vp) and speckle tracking (peak strain rate Esr). Load dependency of DIVPG and untwisting rate was evaluated using a passive leg raising maneuver.ResultsWe included 154 subjects, aged between 18 to 77 years old, 63% were male. Test-retest reliability for color Doppler-derived DIVPG measurements was good, the intraclass correlation coefficients were 0.97 [0.91–0.99] and 0.97 [0.67–0.99] for intra- and inter-observer reproducibility, respectively. Peak DIVPG was positively correlated with peak untwisting rate (r = 0.73, P < 0.001). On multivariate analysis, peak DIVPG was the only diastolic parameter that was independently associated with untwisting rate. Age and gender were the clinical predictive factors for peak untwisting rate, whereas only age was independently associated with peak DIVPG. Untwisting rate and DIVPG were both load-dependent, without affecting their relationship.ConclusionsColor Doppler-derived peak DIVPG was quantitatively and independently associated with peak untwisting rate. It thus provides a reliable flow-based index of early left ventricular diastolic function.

Reduced Exercise Capacity in Diabetes Mellitus Is Not Associated with Impaired Deformation or Twist

Exercise capacity is frequently reduced in people with diabetes mellitus (DM) and may be due to subclinical cardiac dysfunction. Speckle-tracking echocardiography is now widely available; however, the clinical utility and significance of left ventricular (LV) strain and twist parameters remain uncertain. We hypothesized that LV strain and twist would be reduced in DM subjects during exercise. Adults with type 1 or type 2 DM and age- and sex-matched controls performed cardiopulmonary exercise testing (VO2 peak) and supine bicycle exercise echocardiography. Detailed echocardiographic assessment of biventricular function was performed at baseline and repeated during incremental exercise to maximal intensity. Of the 60 participants completing the study protocol, 51 (34 DM, 17 controls; mean age, 42±13years; 69% male; DM duration, 16±10years) had sufficient image quality to assess LV deformation and twist mechanics at rest. Of these, 38 (25 DM, 13 controls) were able to be assessed immediately after exercise. Baseline LV systolic and diastolic function using standard echocardiography measurements were similar between groups. Resting LV global longitudinal strain, twist, twist rate and untwist rate, and the corresponding peak exercise and reserve measures did not differ significantly. As compared with the control subjects, exercise capacity was reduced in the DM cohort (VO2 peak 33±10 vs 41±12mL/minute/kg; P=.02); however, no correlation was observed between VO2 peak and LV twist reserve (R=0.28, P=.09), LV twist rate reserve (R=0.14, P=.39), or LV untwist rate reserve (R=0.24, P=.14). Despite reduced VO2 peak, LV twist mechanics at rest and after maximal intensity exercise did not differ significantly in a cohort of asymptomatic DM subjects with normal resting LV systolic and diastolic function compared with age- and sex-matched controls. This would suggest that exercise capacity can be reduced in the absence of subclinical cardiac dysfunction and that noncardiac factors should be considered as alternative explanations.

P3365Relationship between early diastolic intra-ventricular pressure gradient shortly after aortic valve closure estimated by vector flow mapping and left ventricular diastolic untwisting rate in humans

Abstract Background Early diastolic suction is an important determinant of early diastolic function. Previous studies using color Doppler M-mode and speckle-tracking echocardiography have shown left ventricular (LV) early diastolic LV untwisting rate is directly related to LV intra-ventricular pressure gradient (IVPG) between LV base and apex during early diastole. Recent introduction of vector flow mapping (VFM) using combination of color Doppler and speckle-tracking echocardiography provides noninvasive and feasible assessment of early diastolic IVPG shortly after aortic valve closure including isovolmic relaxation period (ED-IVPG) in humans. However, relationship between VFM–derived ED-IVPG and early diastolic LV untwisting rate has not been well investigated. Purpose The purpose of this study was to examine relationship between ED-IVPG estimated by VFM and LV untwisting rate by speckle-tracking echocardiography. Methods The study population consists of 66 patients without segmental wall motion abnormality, significant valvular diseases, and atrial fibrillation who underwent echocardiography for evaluation of LV function (age: 60±15 years, LVEF: 49±16%). From the apical long-axis views by color Doppler echocardiography, we analyzed peak ED-IVPG between LV base and apex just after aortic valve closure (figure) using commercially available VFM analysis software (DAS-RS1, Hitachi). We assessed peak early diastolic LV untwisting rate and LV torsion from LV basal and apical short-axis view by speckle-tracking echocardiography. We evaluated correlation between ED-IVPG and LV untwisting rate. We also evaluated correlation between ED-IVPG and peak systolic LV torsion, LV end-diastolic (EDV) and end-systolic volumes (ESV), ejection fraction (EF), early diastolic velocity (E) of LV inflow, average early diastolic velocity (e') of mitral annulus, and average E/e'. Results In all the study patients, ED-IVPG was successfully and quickly evaluated. 1) ED-IVPG correlated well with peak LV untwisting rate (r=0.64, p&lt;0.0001). 2) ED-IVPG significantly correlated with LV torsion, LVEDV, LVESV, and LVEF (r=0.47, r=−0.48, r=−0.46, and r=0.48, respectively, p&lt;0.001). 3) There were no significant correlations between ED-IVPG and other indexes including E, average e', and average E/e'. According to receiver operating characteristic analysis, the best cut-off value of ED-IVPG for determining impaired LV untwisting rate (&lt;80 degrees/s) was found at 0.42 mmHg (sensitivity 81%, specificity 76%, and area under the curve 0.86) ED-IVPG measurement by VFM Conclusions The present results showed that noninvasive VFM-derived peak ED-IVPG shortly after aortic valve closure is related to early diastolic peak LV untwisting rate. ED-IVPG easily and quickly estimated by VFM may be used as an additional index for LV diastolic function.

Recovery of Left Ventricular Twist and Left Ventricular Untwist Rate in Patients with ST-segment Elevation Acute Myocardial Infarction

Background: Left ventricular (LV) functional recovery and morphological remodeling after acute myocardial infarction (AMI) followed by reperfusion remain incompletely understood. The aim of the study was to describe the recovery of LV twist (LVT) and LV untwist rate (LVUR) upon revascularization after AMI using two-dimensional (2D) speckle tracking. Methods: We evaluated 88 subjects: 22 normal volunteers (mean age 31 ± 5 years), and 66 patients with AMI (mean age 65 ± 12 years), of which 40 had an inferior AMI and 26 an anterior one. All AMI patients had ST-segment elevation. Echocardiography was performed in all subjects. Patients were scanned within 36 h (baseline) after revascularization (percutaneous coronary intervention) and after 4 months (4 mFU). Apical and basal short-axis images were acquired (frame rate 67 ± 5 frames/s) and analyzed offline to extract the rotation (rate) curves. From these, maximal systolic LVT and peak LVUR were derived. Finally, the infarct size (IS) was estimated based on magnetic resonance imaging delayed enhancement and expressed as a percentage of the total LV volume. Results: At 36 h, LVT and LVUR were significantly reduced in both AMI groups when compared to normals. At 4 mFU, both AMI groups showed recovery in ejection fraction (EF) and reduction in IS (7.24 ± 10.07 vs. 20.13 ± 13.9, P &lt; 0.0001 for inferior AMI and 13.13 ± 10.3 vs. 24.40 ± 15, P &lt; 0.0001 for anterior AMI). LVT and LVUR increased significantly but remained below normal levels. Correlation of LVT and LVUR with IS was significant, but weak (r = 0.34 and r = 0.34, respectively). In addition, a fair correlation of LVT with EF (r = 0.64) and a weak correlation of LVUR with end-diastolic volume (r = 0.43) were found. Conclusion: LVT and LVUR are reduced in AMI patients early after reperfusion and recover incompletely upon follow-up. Interestingly, recovery of LVT characteristics as measured with this 2D speckle tracking-based method showed to be independent of infarct location or extent. LVT and LVUR might be good parameters to monitor the recovery of global LV function after treatment.

Comparison of the Diastolic Stress Test With a Combined Resting Echocardiography and Biomarker Approach to Patients With Exertional Dyspnea: Diagnostic and Prognostic Implications

ObjectivesThis study sought to establish the diagnostic and prognostic value of a strategy for prediction of abnormal diastolic response to exercise (AbnDR) using clinical, biochemical, and resting echocardiographic markers in dyspneic patients with mild diastolic dysfunction. BackgroundAn AbnDR (increase in left ventricular filling pressure) may indicate heart failure with preserved ejection fraction as the cause of symptoms in dyspneic patients, despite a nonelevated noncardiac at rest. However, exercise testing may be inconclusive in patients with noncardiac limitations to physical activity. MethodsIn 171 dyspneic patients (64 ± 8 years) with suspected heart failure with preserved ejection fraction but resting peak early diastolic mitral inflow velocity/peak early diastolic mitral annular velocity ratio (E/e′) <14, a complete echocardiogram (including assessment of myocardial deformation and rotational mechanics) and blood assays for biomarkers were performed. Echocardiography following maximal exercise was undertaken to assess AbnDR (exertional E/e′ >14). Patients were followed over 26.2 ± 4.6 months for endpoints of cardiovascular hospitalization and death. ResultsAbnDR was present in 103 subjects (60%). Independent correlates of AbnDR were resting E/e′ (odds ratio [OR]: 8.23; 95% confidence interval [CI]: 3.54 to 9.16; p < 0.001), left ventricular untwisting rate (OR: 0.60; 95% CI: 0.42 to 0.86; p = 0.006), and galectin-3—a marker of fibrosis (OR: 1.80; 95% CI: 1.21 to 2.67; p = 0.004). The use of resting E/e′ >11.3 and galectin-3 <1.17 ng/ml to select patients for further diagnostic processing would have allowed exercise testing to be avoided in 65% of subjects, at the cost of misclassification of 13%. The composite outcome of cardiovascular hospitalization or death occurred in 47 patients (27.5%). The predictive value of an AbnDR response and the combined strategy (resting echocardiography and galectin-3 or exercise testing in case of an inconclusive first step) showed similar event prediction (36 vs. 34; p = 0.95). ConclusionsThe implementation of a 2-step algorithm (echocardiographic evaluation of resting E/e′ followed by the assessment of galectin-3) may improve the diagnosis and prognostic assessment of individuals with suspected heart failure with preserved ejection fraction who are unable to perform a diagnostic exercise test.

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

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. 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 (4×4min at 90%-95% of maximal heart rate, three times a week, 120min/wk; n=24) or MIE (210min/wk; n=23) for 12weeks 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. In total, 37 subjects completed 12weeks 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. 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.

0157: Echo-based diastolic intraventricular pressure difference as a surrogate of left ventricular untwisting

Left ventricular (LV) early diastolic filling is related to an active process of LV relaxation, caused by its rapid untwisting. The untwisting rate (UR) has been reported to be a robust marker of diastolic function but is technically hard to assess in practice. The untwisting phenomenon generates a diastolic intraventricular pressure gradient (IVPGd), which can be assessed by colour Doppler M-Mode. Previous studies showed a close temporal relation between the UR and the IVPGd peaks, but the relation between their magnitudes as well as their load dependency remain unclear. We developed our own Matlab software for IVPGd assessment by colour Doppler M-Mode based on Bernoulli equation. From our research database, we retrieved all echocardiograms where ejection fraction was normal, the colour M-Mode tracing was available and UR was measurable using speckle tracking. Passive leg raising was used in 19 healthy volunteers to study the impact of preload on the IVPGd measurement. We included 104 echocardiograms (83% males, median age 23y [19-69]). The median peak IVPGd was 3.1mmHg [1.6-7.8] and correlated to the peak UR (r=0.57, P<0.0001, figure). There was also a significant correlation between the IVGPd peak and E’ (r=0.62, P<0.0001). For peak IVPGd, correlations between inter- and intra-observer measures were calculated on 10 randomly selected subjects and were 0.83 and 0.99 (P<0.05). Compared to UR and E’, IVPGd was also significantly increased with leg lifting (2.7±0.8mmHg vs 3.3±0.8mmHg, P<0.001). Peak IVPGd based on colour Doppler M mode echocardiography is positively correlated to the LV UR. Despite the observation that IVPGd is not less load-dependent than other parameters, it requires only an echo loop easily obtained during routine clinical studies and is highly reproducible using a semi-automatic software algorithm. This new tool could easily become a new practical echo index for diastolic function assessment. Abstract 0157 - Figure

The impact of an experimentally induced increase in arterial blood pressure on left ventricular twist mechanics.

The effects of isometric hand-grip exercise (IHG) coupled with a period of postexercise circulatory occlusion (OCC; known to sustain exercise-induced increases in blood pressure while facilitating a decrease in heart rate) on left ventricular (LV) twist mechanics was examined. Two-dimensional speckle-tracking echocardiography was used to assess LV apical and basal rotation and LV twist in 19 healthy participants (23 ± 2 years old) at rest, during 3 min of IHG (performed at 40% maximal voluntary contraction) and 3 min of OCC immediately following IHG. The IHG elicited significant (P < 0.001) increases in mean arterial pressure (rest, 91 ± 1 mmHg; IHG, 122 ± 2 mmHg) and heart rate (rest, 65 ± 2 beats min(-1); IHG, 91 ± 4 beats min(-1)). Mean arterial pressure remained elevated during OCC (116 ± 2 mmHg; P < 0.001 versus rest), whereas heart rate returned to resting levels (68 ± 3 beats min(-1); P = 0.159 versus rest). Apical rotation decreased significantly (P < 0.01) by 10 ± 5% during IHG and 21 ± 4% during OCC, whereas basal rotation remained unchanged from rest. Left ventricular twist decreased from rest to IHG (12 ± 5%; P = 0.015) and OCC (21 ± 4%; P = 0.001), whereas a decrease in LV untwist rate was observed only during OCC. An increase in blood pressure generated by IHG, and maintained by a period of OCC, impairs aspects of LV twist mechanics. Postexercise circulatory occlusion isolated the effect of the arterial blood pressure rise (from heart rate), magnifying the impairment of LV twist mechanics when compared with IHG, whilst also negatively impacting LV relaxation. We propose that a protocol using isometric exercise followed by circulatory occlusion provides a method for studying the effects of blood pressure changes on LV twist mechanics.

Left Ventricular Rotational Mechanics in Preterm Infants Less Than 29 Weeks’ Gestation over the First Week after Birth

There is a paucity of data on left ventricular (LV) rotational physiology, twist, and torsional mechanics in preterm infants. The principal aims of the present study were to assess the feasibility and reproducibility of measuring LV rotation, twist, and torsion in preterm infants (<29 weeks' gestation) using two-dimensional speckle-tracking echocardiography and to examine the changes in those parameters over the first week after birth. This was a prospective observational study involving preterm infants <29 weeks' gestation. Echocardiographic evaluations were performed on days 1, 2, and 5 to 7 after delivery. LV basal and apical rotation, LV twist, LV twist rate (LVTR), and LV untwist rate (LVUTR) were measured from the basal and apical short-axis parasternal views and calculated using two-dimensional speckle-tracking echocardiography. Torsion was also calculated by normalizing LV twist to LV end-diastolic length. One-way repeated-measures analysis of variance was used to compare values across the three time points. Intra- and interobserver reproducibility were assessed using Bland-Altman analysis and the intraclass correlation coefficient. Fifty-one infants with a mean ± SD gestational age of 26.8 ± 1.5 weeks and a mean birth weight of 945 ± 233 g were included. There was high intra- and interobserver reproducibility for basal and apical rotation, LV twist, and LV torsion, with intraclass correlation coefficients ranging from 0.78 to 0.96 (P < .001 for all). Intra- and interobserver intraclass correlation coefficients for LVTR and LVUTR ranged from 0.70 to 0.88 (P < .001 for all). Apical rotation remained constant over the first week of age in a positive counterclockwise fashion (11.8 ± 5.0° vs 12.1 ± 6.1° vs 11.7 ± 8.3°, P = .92). Basal rotation changed from counterclockwise on day 1 to clockwise on day 7 (median, 5.5° [interquartile range, -0.3° to 8.3°] vs 4.0 [interquartile range, -4.7° to 7.2°] vs -4.5° [interquartile range, -5.8° to -2.3°], P < .001), with resultant net increases in twist and torsion (P < .05). There was no change in LVTR (P = .60), but LVUTR increased across the same time period (P = .01). Assessment of twist, LVTR, and LVUTR is feasible in preterm infants, with acceptable reproducibility. There are increases in LV twist and torsion in addition to LVUTR, suggesting changes in LV mechanics during the first week of age.

Echocardiographic evaluation of left ventricular diastolic function: an update.

Echocardiographic evaluation of diastolic properties and assessment of hemodynamic status of the right and the left ventricle have been traditionally applied for many years in clinical practice. Establishment of diagnosis of diastolic dysfunction, grading, and estimation of filling pressures noninvasively adds prognostic information to the clinician, which may affect treatment management. Novel methods, including left atrium strain, left ventricular diastolic strain rate, and left ventricular untwisting rate, have been imported in clinical practice attempting to provide a more comprehensive and more accurate understanding of the mechanisms and diagnosis of diastolic dysfunction.

Left Ventricular Rotational Mechanics before and after Exercise in Children

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. 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. 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. 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.

Does the metabolic syndrome impact left-ventricular mechanics? A two-dimensional speckle tracking study.

To evaluate left-ventricular mechanics estimated by two-dimensional echocardiography (2DE) speckle tracking analyses in patients with the metabolic syndrome. This cross-sectional study included 95 untreated patients with metabolic syndrome and 65 controls similar by sex and age. Metabolic syndrome was defined by the presence of at least three ATP-AHA-NHLB criteria. All the patients underwent adequate laboratory analyses and complete 2DE examination. 2DE global longitudinal and circumferential strain was significantly decreased in the metabolic syndrome group, whereas 2DE global radial strain was similar between the observed groups. The left-ventricular torsion was similar between the metabolic syndrome participants and the controls; whereas the left-ventricular untwisting rate was significantly increased in the metabolic syndrome group. The increasing number of the metabolic syndrome criteria induces progressive reduction of the left-ventricular longitudinal strain from the individuals with no metabolic syndrome risk factors to the individuals with five metabolic syndrome criteria. The same pattern was not noticed for left-ventricular circumferential and radial strain. The combination of increased blood pressure, abdominal obesity and increased fasting glucose level was associated with the higher level of left-ventricular mechanical impairment comparing with other clusters of the metabolic syndrome components. The multivariate analysis of the metabolic syndrome criteria showed that 24-h mean blood pressure, waist circumference and fasting glucose level were independently associated with 2DE global longitudinal and circumferential myocardial strain, and left-ventricular untwisting rate. The interaction between sex and metabolic syndrome significantly impacts the left-ventricular longitudinal strain and untwisting rate. Left-ventricular mechanics assessed by 2DE strain is significantly impaired in the metabolic syndrome patients. Among all metabolic syndrome components, blood pressure, waist circumference and fasting glucose level are the most responsible for damage of left-ventricular deformation.

Assessment of left ventricular twist mechanics in Tako-tsubo cardiomyopathy by two-dimensional speckle-tracking echocardiography

To assess left ventricular (LV) twist mechanics in patients with Tako-tsubo cardiomyopathy (TTC). Two-dimensional strain and LV twist by speckle-tracking echocardiography was performed in 17 consecutive patients with typical TTC according to the Mayo clinic criteria [78 ± 8 years, 88% women, and mean left ventricular ejection fraction (LVEF) 45 ± 10%], at the acute phase (within 24 h after admission) and after recovery (1 month later). Seventeen control (C) patients matched for age and sex (mean LVEF 70 ± 7%), and 17 patients with acute anterior myocardial infarction (MI) treated by successful primary angioplasty 24 h before, matched for LVEF, age, and sex, were compared with TTC patients. LV twist was assessed using the parasternal basal and apical short-axis planes, and defined as the net difference in degrees of apical (Ar) and basal rotation (Br). Peak systolic and early diastolic, apical (As and Ad) and basal (Bs and Bd) rotation rate, and LV twisting rate (TR) and untwisting rate (UR) (in °/s) were derived from rotational and twist curves. The time sequences were normalized to the percentage of systolic duration. At the acute phase, Ar, As, Ad, Bs, LV twist (10 ± 9° vs. 23 ± 6°), LV TR, and LV UR were significantly impaired in patients with TTC when compared with controls (all, P < 0.05). Patients with MI displayed intermediate values (P = NS vs. TTC, and P < 0.05 vs. C). However, in the subgroup of patients with electrocardiogram ST-segment elevation at presentation (n = 12 TTC and 17 MI), several LV twist mechanics parameters were significantly reduced in TTC patients when compared with MI patients, LV twist, and LV TR being the most significant factors (all, P≤ 0.01). Abnormal reversed Ar (clockwise when seen from the apex) was seen in three patients (18%) with TTC vs. none in the other groups. A significant correlation between LV twist and LVEF, LV volumes, wall motion score index, and plasma NT-pro BNP was observed in the TTC group (all, P < 0.05). At follow-up, LV twist mechanics improved significantly in TTC patients (all, P < 0.05 vs. acute phase), who had final values similar to C (all, P = NS), whereas the magnitude of improvement was lower in MI patients (P ≤ 0.05 vs. TTC). LV twist mechanics is significantly impaired in patients with TTC mainly due to a severe reduction in apical function and is entirely reversible. Furthermore, in the subgroup of patients with ST-segment elevation, the early post-admission evaluation of LV twist mechanics is more severely impaired in TTC when compared with MI.

Evaluation of Left Ventricular Twist in Acute Myocardial Infarction Patients Using Speckle Tracking Imaging

The aim of this study is to evaluate the differences of left ventricular (LV) twist and untwisting rate in patients with acute myocardial infarction (AMI) as compared with healthy subjects by means of Speckle Tracking Imaging (STI). 45 AMI patients (AMI group) and 48 healthy subjects (NOR group) were studied. Two-dimensional STI was performed in all patients. Peak apical rotation, peak basal rotation, peak LV twist, peak basal untwisting rate, peak apical untwisting rate, peak LV untwisting rate, time to peak LV twist, and untwisting rate were measured. In comparison with the NOR group, peak LV rotational parameters were found to be decreased in the AMI group (P < 0.01). A strong correlation was found between the peak LV twist and LV ejection fraction in the overall study population (P < 0.001). The LV twist is strongly related to LV systolic function, and the impairment of LV function observed in patients with AMI is associated with a decrease of LV twist and untwist rate. The STI appears to accurately evaluate LV function.

The Left Ventricle Responds to Acute Graded Elevation of Right Ventricular Afterload by Augmentation of Twist Magnitude and Untwist Rate

The right and left ventricles share the interventricular septum, which mechanically transmits pressure gradients. The aim of this study was to investigate how acute mild or moderate right ventricular (RV) afterload affects left ventricular (LV) function. In 14 open-chest pigs (mean weight, 43 ± 4 kg) with preserved pericardium, acute mild (>35 and ≤50 mm Hg) and moderate (>50 and ≤60 mm Hg) RV pressure loading conditions were induced by constriction of the pulmonary artery. Hemodynamic parameters and LV twist and untwist were evaluated under each condition. From baseline to mild and moderate RV afterload, the mean RV systolic pressure increased from 31.0 ± 4.3 to 41.1 ± 2.7 and 52.7 ± 3.4 mm Hg (P < .001), while LV twist magnitudes increased from 15.4 ± 5.1° to 18.5 ± 3.1° and 19.8 ± 5.0° (P= .004), respectively. Absolute values of LV untwist rate increased from -116.9 ± 64.9°/sec to -160.0 ± 53.3°/sec and -169.1 ± 47.0°/sec, respectively (P= .001). After adjusting for all variables, only the ratio of the early and atrial components of mitral inflow and RV outflow tract acceleration time was significantly associated with the LV twist magnitude and LV untwist rate. In an acute setting, the left ventricle responds to suddenly elevated RV afterload and decreased RV stroke volume by promptly increasing its twist magnitude and untwist rate.

Characteristics of left ventricular rotational mechanics in patients with systemic amyloidosis, systemic hypertension and normal left ventricular mass

Recently, two-dimensional (2D) speckle-tracking echocardiography has enabled assessment of a particular behaviour of left ventricular (LV) motion defined as twisting/untwisting. The aim of our study is to evaluate whether in early stage of hypertension and systemic amyloidosis, subclinical alteration of LV twist and untwist is already present even if no LV hypertrophy is evidenced. Forty-seven patients with light chain immunoglobulin amyloidosis (AL) entered the study and were classified having cardiac amyloidosis (CA) or not (NCA) if the mean value of LV wall thickness was ≥12 mm or not. Twenty-two consecutive patients with history of arterial essential hypertension (Hyp Group) and no sign of LV hypertrophy were enrolled. A total of 26 asymptomatic healthy subjects, age-matched, were analysed as control group. All three groups of patients and healthy subjects underwent traditional and 2D speckle-tracking echocardiography evaluation. LV diameters, volumes, wall thickness, mass, ejection fraction, E/A and E/E' ratio were evaluated. Twisting and untwisting rates were significantly increased in NCA and Hyp group when compared with CA and control group. Moreover, despite similar LV mass and diastolic dysfunction degree, untwisting rate peak was significantly delayed in NCA when compared with Hyp group. In patients with CA, untwisting rate delay was similar to patients with NCA. Our results show that amyloidosis and systemic hypertension produce both LV twist and untwist rate enhancement before LV hypertrophy is developed. In patients with amyloidosis irrespectively of LV infiltration degree, a significant LV untwisting rate peak delay occurs suggesting that different aetiology of cardiac involvement could differently affect LV untwisting rate.

Role of pericardium in the maintenance of left ventricular twist

BackgroundThe role of pericardium in left ventricular (LV) twist has not been directly investigated. We sought to determine the role of pericardium in maintenance of LV twist function in an...

Echocardiography and a quest of the promised land of the accurate assessment of cardiac mechanics

This editorial refers to ‘Feasibility and reproducibility of left ventricular rotation parameters measured by speckle tracking echocardiography’ by Bas M. van Dalen et al ., pp. 669–76, ‘Interpretation of two-dimensional and tissue Doppler-derived strain (1) and strain rate data: is there a need to normalize for individual variability in left ventricular morphology?’ by David Oxborough et al ., pp. 677–82, and ‘Echocardiographic assessment of left ventricular untwist rate: comparison of tissue Doppler and speckle tracking methodologies’ by V. Ferferieva et al ., pp. 683–90, in this issue. Echocardiography is in the midst of revolution. Its cause is the emergence of the new techniques to quantify segmental systolic and diastolic function. However, as in all revolutions, ‘old’ ways may be held in low esteem, whereas ‘new’ ways are held in awe, although frequently with insufficient information to support these views. Early in this last decade, we witnessed the emergence of segmental strain measurements based on tissue Doppler imaging (TDI). While initial studies showed good correlation with magnetic resonance imaging, later studies demonstrated that, compared with assessment of velocities, variability in the measurement of strain was much higher. Additionally, this new method required defining normal ranges of segmental strain as functions of age, gender, and wall location within the heart, work that has not yet been fully completed.1 Fast on the heels of TDI-based strain, speckle tracking echocardiography (STE) has been introduced, …

Echocardiographic assessment of left ventricular untwist rate: comparison of tissue Doppler and speckle tracking methodologies

The study was designed to test the influence of the temporal resolution, at which tissue Doppler imaging (TDI) and speckle tracking imaging (STI) operate, on the accurate assessment of left ventricular (LV) untwist rate (UR). Echo imaging and invasive LV pressure measurements were performed during right atrial (RA) pacing and dobutamine challenge in eight pigs. LV torsion and torsional rate profiles were analysed from grey scale and tissue Doppler data (apical and basal short axis) at frame rates of 82 +/- 17 and 183 +/- 14 Hz, respectively. Temporal subsampling of TDI data sets was performed at 82 +/- 6 Hz in order to mimic the mean temporal resolution of STI and the LV torsional curves were again extracted. At rest, LV UR values were comparable for both imaging techniques. However, during dobutamine stimulation, TDI estimated peak UR was predominantly higher than UR measured by STI (-112.1 +/- 64.5 degrees /s vs. -75.5 +/- 31.4 degrees /s, P < 0.05). The similarity of LV UR measurements with respect to the STI/TDI data was examined by a Bland-Altman analysis. Although both methods regarding LV UR correlated well, these methods cannot be interchanged. STI showed a bias to underestimate UR at high values.

Letter by Dwivedi et al Regarding Article, “Left Ventricular Untwisting Rate by Speckle Tracking Echocardiography”

To the Editor: We read with interest the article by Wang et al1 that compared left ventricular (LV) twist, twisting rate, and untwisting rate (UR) in subjects with LV systolic dysfunction and depressed ejection fraction (EF), subjects with diastolic dysfunction and normal EF, and 20 healthy subjects by speckle tracking echocardiography. This study highlights major issues in LV diastolic function. However, we believe that it contains some limitations that could modify interpretation of the conclusions. The main result of the clinical study is that LV twist, twisting rate, and UR are …