Peak Left Ventricular Twist Research Articles

Intra‐ and interscan reproducibility using Fourier Analysis of STimulated Echoes (FAST) for the rapid and robust quantification of left ventricular twist

To assess the intra- and interscan reproducibility of LV twist using FAST. Assessing the reproducibility of the measurement of new MRI biomarkers is an important part of validation. Fourier Analysis of STimulated Echoes (FAST) is a new MRI tissue tagging method that has recently been shown to compare favorably with conventional estimates of left ventricular (LV) twist from cardiac tagged images, but with significantly reduced user interaction time. Healthy volunteers (N = 10) were scanned twice using FAST over 1 week. On day 1, two measurements of LV twist were collected for intrascan comparisons. Measurements for LV twist were again collected on day 8 for interscan assessment. LV short-axis tagged images were acquired on a 3 Tesla (T) scanner to ensure detectability of tags during early and mid-diastole. Peak LV twist is reported as mean ± SD. Reproducibility was assessed using the concordance correlation coefficient (CCC) and the repeatability coefficient (RC) (95% confidence interval [CI] range). Mean peak twist measurements were 13.4 ± 4.3° (day 1, scan 1), 13.6 ± 3.7° (day 1, scan 2), and 13.0 ± 2.7° (day 8). Bland-Altman analysis resulted in intra- and interscan bias and 95% CI of -0.6° [-1.0°, 1.6°] and 1.4° (-1.0°, 3.0°), respectively. The Bland-Altman RC for peak LV twist was 2.6° and 4.0° for intra- and interscan, respectively. The CCC was 0.9 and 0.6 for peak LV twist for intra- and interscan, respectively. FAST is a semi-automated method that provides a quick and quantitative assessment of LV systolic and diastolic twist that demonstrates high intrascan and moderate interscan reproducibility in preliminary studies.

Feasibility and reproducibility of peak left ventricular twist in children with and without heart disease

Feasibility and reproducibility of peak left ventricular twist in children with and without heart disease

Left ventricular twist and shear-angle in patients with mitral regurgitation

Background Mitral regurgitation(MR) is a common valvular disorder that foments left ventricular(LV) dysfunction. The study of LV twist during the progression of MR is limited to studies performed with ultrasound/echo(1-3) in human subjects or animal studies(4), which suggest that LV twist decreases when MR is present. LV circumferential-longitudinal shear angle (CL-shear angle) has been proposed as a more reproducible measure of LV rotational mechanics, but has not been evaluated in patients with MR. We hypothesized that both LV twist and CL-shear angle would decrease with severity of MR. Methods Normal subjects(n=54), moderate MR patients(n=29), and severe MR patients(n=54) were studied after obtaining informed consent. MRI was performed on a 1.5T scanner (Signa, GE Healthcare, Milwaukee, WI) and grid tagged LV images were collect from the base to the apex(7). LV twist and CL-shear angle measurements were derived from Fourier Analysis of STimulated echoes(FAST)(8). LV twist is defined as the difference in rotation at the apex relative to the base of the heart. Shear-angle is defined as the difference in rotation at the apex times the radius of the apex relative to the base times the radius of the base, divided by the distance between the apex and base(5, 6). Peak LV twist and peak CL-shear angle from the three groups were compared using a one-way ANOVA and Tukey’s least significant difference(LSD) procedure for multiple comparisons. Results Mean peak LV twist for normal subjects, moderate MR patients, and severe MR patients were: 11.5±3.2, 9.0±3.0, 8.8±2.6, respectively. Mean peak CL-shear angle for normal subjects, moderate MR patients, and severe MR patients were: 5.0±1.4, 4.7±1.6, 5.0±1.3 respectively. The one-way ANOVA of peak twist between the groups, showed differences among the groups(p<0.0001). Further investigation with LSD, showed a significant difference between the normal subjects and the moderate MR patients and between the normal subject group and the severe MR patients. However, the one-way ANOVA of peak shear-angle did not reveal any differences between the three groups(p=0.4).

Left Ventricular Rotational Dynamics in Beta Thalassemia Major: A Speckle-Tracking Echocardiographic Study

Iron-mediated cardiomyopathy is the leading cause of death in patients with thalassemia major (TM). The identification of subclinical cardiac involvement in the early phases of the disease is important to optimize therapeutic strategies. The aim of this study was to identify early markers of cardiac dysfunction through new parameters of cardiac rotational dynamics and to look for a relationship with parameters of iron overload. Twenty-seven asymptomatic patients with TM and 27 healthy control subjects were prospectively enrolled. All subjects underwent standard echocardiography and subsequent offline analysis to assess left ventricular (LV) rotation and longitudinal mechanics using speckle-tracking echocardiography. In all patients with TM, ferritin levels were measured, and a subgroup underwent cardiac magnetic resonance imaging. All subjects had normal parameters of cardiac function, although patients with TM showed significantly lower S' values (P= .030) and E' values (P= .025), with increased E/E' ratio (P= .003) and indexed left atrial volumes (P= .022). Compared with controls, patients with TM had significantly reduced systolic apical rotation (P= .006), LV twist (P= .002), and LV torsion (P= .001). Systolic and diastolic rotational peak velocities at the apical level were also significantly decreased in the TM group (P= .003 and P= .011, respectively) with reductions of twisting and untwisting rates (P= .003 and P= .001, respectively). Patients with TM also showed a significant reduction of longitudinal displacement from the two-chamber apical view (P= .042) but preserved longitudinal strain and strain rate. Patients with T2* values > 20 msec had preserved rotational function, while those with T2* values < 20 msec showed significantly lower mean values of LV peak basal systolic rotation (-3.1 ± 1.4° vs -6.2 ± 2.6°, P= .016), LV peak apical systolic rotation (3.4 ± 1.3° vs 6.4 ± 3.1°, P= .045), LV twist (4.8 ± 2.5° vs 10.9 ± 4.9°, P= .012), and LV torsion (0.6 ± 0.2°/cm vs 1.4 ± 1.6°/cm, P= .010). LV torsion was negatively related to ferritin levels (r= -0.47, P= .013) and directly to T2* values (r= 0.64, P= .007). LV rotational dynamics in asymptomatic patients with TM are negatively related to iron overload. Rotational function of the left ventricle is preserved in patients with normal T2* values. These new parameters are useful for an early diagnosis of cardiac involvement.

Normal left ventricular ejection fraction and mass but subclinical myocardial dysfunction in patients with Friedreich's ataxia

Myocardial involvement in Friedreich's ataxia (FRDA) is characterized by iron deposits, diffuse fibrosis, and focal necrosis. We hypothesized that subclinical left ventricular (LV) dysfunction may occur in 'FRDA patients who have normal LV ejection fraction (LVEF) and mass. Twenty patients homozygous for the GAA expansion in the frataxin gene (mean age: 35 ± 16 years) and twenty age- and sex-matched controls (mean age: 34 ± 15 years) were studied using conventional echocardiography and speckle-tracking imaging. The two groups did not differ in terms of the LVEF (68 ± 6 vs. 67 ± 6%, in patients and controls, respectively) or LV mass (91 ± 20 vs. 82 ± 17 g/m(2)). Global systolic longitudinal (-15.3 ± 2.1 vs. -17.5 ± 1.6%, P = 0.001) and circumferential (-19.5 ± 2.9 vs. -21.4 ± 2.6%, P = 0.034) strain, and peak LV twist (9.2 ± 3.3 vs. 11.7 ± 2.3°, P = 0.008) were significantly reduced in patients compared with controls. Indexed stroke volume was also significantly lower in patients (36 ± 5 vs. 43 ± 8 mL/m(2), P = 0.0012) and this decreased LV pump performance was associated with a concentric remodelling pattern (relative wall thickness: 0.47 ± 0.08 vs. 0.35 ± 0.05, P < 0.001). There is evidence of morphological and functional abnormalities in FRDA patients with normal LVEF and mass.

Left Ventricular Twist Mechanics in Hypertrophic Cardiomyopathy Assessed by Three-Dimensional Speckle Tracking Echocardiography

Left ventricular (LV) twist represents a phenomenon that links systolic contraction with diastolic relaxation and plays a major role in cardiac physiology; thus, the study of twist mechanics is of particular interest in hypertrophic cardiomyopathy (HC). Three-dimensional speckle tracking echocardiography (3D-STE) has the potential to overcome the limitations of 2-dimensional imaging and provide a greater understanding of LV twist in HC. We aimed to examine LV twist mechanics in HC using 3D-STE. Echocardiograms from subjects with a diagnosis of HC were examined for 3D-STE analysis. Age- and gender-matched healthy subjects were tested as a control group. Forty patients with HC (age 37 ± 16 years; 42.5% women) and 40 control subjects (age 35 ± 10 years; 42.5% women) were examined. Compared with the controls, the patients with HC showed increased peak LV twist (16.5 ± 4.7° vs 12.0 ± 3.9°, p <0.001) mainly because of increased apical rotation of those with LV outflow tract obstruction (obstruction, 12.7 ± 4.4° vs nonobstruction, 9.7 ± 2.8°, p = 0.02). In addition, the patients with HC displayed onset of torsion recoil occurring closer to the aortic valve closure (94 ± 6% vs 85 ± 6%, p <0.001; time normalized by the length of systole), limited completion of untwist during early diastole (31 ± 12% vs 62 ± 15%, p <0.001), and delayed peak untwist velocity (22 ± 7% vs 13 ± 9%, p <0.001; time normalized by the length of diastole). In conclusion, the evaluation of twist mechanics using 3D-STE provides novel insight regarding alterations in LV mechanics in patients with HC. Elucidating the characteristics of the wringing motion of the heart might help to broaden the understanding of the hyperdynamic contraction and impaired relaxation observed in these patients.

Left Ventricular Torsional Mechanics in Uncomplicated Pregnancy

Alterations in left ventricular (LV) twist (torsion) and untwist have been described for a variety of physiologic and pathologic conditions. Little information is available regarding changes in these parameters during normal pregnancy. Pregnancy is associated with significant changes in LV torsional mechanics. Left ventricular twist and untwist was measured in 32 pregnant females (mean gestation 199 ± 48 d) and 23 nonpregnant controls using speckle-tracking echocardiography. Left ventricular ejection fraction (68 ± 5% vs 66 ± 5%) was similar between the groups (P not significant). There was a significant increase in peak LV twist from nonpregnant controls (9.4 ± 3.7 degrees) to second-trimester (12.0 ± 4.2 degrees) and third-trimester subjects (12.6 ± 5.9 degrees, all P<0.05). Peak LV twist velocity was also increased in second- and third-trimester groups compared with controls (94 ± 24 degrees/sec and 93 ± 30 vs 64 ± 21 degrees/sec, respectively, both P<0.05). Both peak untwist velocity and time to peak untwist velocity were not significantly different between groups (P not significant). Multiple regression analysis indicate that only systolic blood pressure (r = 0.394, P = 0.005) was an independent predictor for increased LV torsion. There are significant changes in LV torsional indices during the course of pregnancy, whereas untwist parameters remain unchanged. Blood pressure is independently associated with increased torsion during pregnancy.

Prolonged left ventricular twist in cardiomyopathies: a potential link between systolic and diastolic dysfunction

Left ventricular (LV) twist and untwist play a major role in LV mechanics. We sought to acquire new pathophysiological insights in cardiomyopathies (CM) studying LV twist dynamics by speckle tracking imaging (STI). Standard echo-Doppler and STI study were performed in 67 CM patients divided in four age- and sex-matched subgroups: 18 with apical hypertrophic cardiomyopathy (Group A); 20 with asymmetrical hypertrophic cardiomyopathy (Group B); 15 with dilated cardiomyopathy (Group C); 14 with LV non-compaction (Group D). As controls, 34 age- and sex-matched normal subjects were studied. Compared with control group, all CM Groups showed significantly lower longitudinal, circumferential, and radial myocardial deformations (P < 0.05). LV twist was correlated with ejection fraction (EF; r = 0.62; P < 0.0001). Furthermore, all CM patients had a significantly lower twist rate (P < 0.05) and delayed onset of untwist (P < 0.01). Of interest a significant correlation was found between isovolumic relaxation time and untwist onset (r= 0.485, P < 0.0001). In addition, a significant correlation was found between longitudinal deformations and the onset of untwist (strain: r = 0.46, P = 0.0001; strain rate: r = 0.33, P = 0.0056) and between longitudinal strain rate and twisting rate (r= -0.38; P = 0.0015). (i) All CM patients show an impairment of longitudinal, circumferential, and radial myocardial deformations; (ii) LV peak twist is impaired only in CM with reduced EF but preserved in those with normal or increased EF; (iii) LV twist is prolonged and untwisting onset is delayed in all CM, suggesting that a mechanical adaptation to subclinical systolic abnormalities might induce, by a prolonged LV twist, the early onset of diastolic dysfunction.

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.

105 Left ventricular twist in patients with Friedreich Ataxia and normal left ventricular ejection fraction and mass

Iron deposits, diffuse fibrosis and focal necrosis are found in Friedreich's cardiomyopathy. We hypothesized that subclinical left ventricular (LV) dysfunction might occur in patients with Friedreich ataxia (FA) who present with normal LV ejection fraction (LVEF) and mass. Twelve patients with FA (mean age: 36 ± 18 years) and twelve age-matched healthy controls (mean age: 36 ± 17 years) were submitted to standard echocardiography. Short axis basal and apical views were analyzed using speckle tracking software. LV twist was defined as the net difference between the apical and basal rotation. The two groups did not differ in terms of LVEF (65 ± 4% and 65 ± 6% in patients and in controls, respectively) and in systolic mitral annular velocities (7.6 ± 1.3 cm/s in patients and 8.3 ± 1.2 cm/s in controls). A slightly higher LV mass index (M-mode, American Society of Echocardiography convention) was observed in the patient group (93 ± 23 g/m_ versus 86 ± 18 g/m_, p = NS). The LV filling parameters did not differ between the 2 groups. However, early diastolic mitral annular velocity (Ea) was lower and the ratio of early transmitral flow velocity to Ea was higher in Friedreich ataxia patients (table). Peak LV twist was significantly reduced in patients as compared to controls, unlike early diastolic LV untwisting (at 5%, 10% and 15% of diastole) which was not significantly different. In patients with FA and normal LVEF and mass, the detection of a reduction in LV twist and an alteration in mitral annular diastolic velocities suggests the presence of subtle myocardial dysfunction. Evaluation of these parameters may prove useful as outcome measures for the assessment and follow-up of new therapies in the early stages of the disease.Empty CellFriedreich patientsControlsP valueE wave velocity (cm/s)73 ± 1073 ± 10NSE/A1.7 ± 0.71.95 ± 0.7NSEa (cm/s)9.3 ± 1.912.1 ± 3.40.02E/Ea8.6 ± 2.16.6 ± 1.90.03Peak LV twist (°)9.2 ± 3.412.1 ± 2.40.02

331 Effect of acute hypoxia on left ventricular twist assessed by speckle tracking imaging

The impact of hypoxia on left ventricular (LV) myocardial contractility remains debated. Objectives: We hypothesized that acute hypoxia in healthy people increases LV twist as a consequence of the cardiovascular adaptation to stress (increased sympathetic nerve activity). Because hypoxia increases heart rate, we aimed to control for this change by studying the same subjects under atropine during normoxia. We studied 21 subjects (mean age: 27 ± 7 years) without medical history. Echocardiography was performed in normoxia and after 30 minutes of hypoxia (12% FiO 2 ). Short axis basal and apical views were analyzed using speckle tracking software. LV twist was defined as the net difference between the apical and basal rotation. The effect of atropine on LV twist was tested in the same subjects under normoxia. As expected, hypoxic breathing decreased arterial saturation in oxygen below 80% (table). Peak LV twist increased, as did heart rate, LV ejection fraction (LVEF) and systolic mitral annular velocity. Despite a decrease in mitral E/A ratio, early diastolic LV untwisting (at 5%, 10% and 15% of diastole) was not significantly modified under hypoxia. Atropine did not alter peak systolic twist (8.9 ± 3.1° versus 10.1 ± 2.6°, p = 0.09, without and with atropine, respectively), despite an increase in heart rate (from 64 ± 11 to 77 ± 11 beats/min, p = 0.0001). Acute hypoxia increases LV twist as well as other parameters of LV contractility. This change in LV twist does not result from the chronotropic effect of hypoxia. Values are means (SD) Normoxia Hypoxia p value SaO 2 (%) 97 (1.3) 76 (7.8) 0.0001 Heart rate (beats/min) 64 (11) 70 (9) 0.008 LVEF (%) 65 (5) 68 (7) 0.011 Systolic mitral annular velocity (cm/s) 8.0 (1.1) 8.7 (1.4) 0.03 E/A 2.1 (0.6) 1.8 (0.4) 0.015 Peak LV twist ( ° ) 8.9 (3.1) 11.1(2.8) 0.003

Differences in Left Ventricular Twist Related to Age: Speckle Tracking Echocardiographic Data for Healthy Volunteers from Neonate to Age 70 Years

To determine normal left ventricular (LV) twist characteristics in different age groups and assess changes between neonates and the elderly. 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. 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. 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.

Left ventricular twist: comparison between two- and three-dimensional speckle-tracking echocardiography in healthy volunteers

left ventricular (LV) twist is the result of clockwise rotation of the base and counterclockwise rotation of the apex. The aims of this study were to investigate the feasibility of the three-dimensional speckle-tracking echocardiography (3DSTE) to assess LV twist values and compare the data measured by two-dimensional speckle-tracking echocardiography (2DSTE) in a group of healthy volunteers. fifty individuals were enrolled in the protocol. LV twist was defined as net difference between averaged 2DSTE apical (4 segments) and basal (6 segments) rotations. 3DSTE twist was obtained from the LV volumetric image and shown as the averaged global value of 16 segments. Time-to-peak by both techniques was also measured and compared. Significant differences between the two techniques were calculated using the paired Student t-test. P-values of <0.05 were considered significant. Reliable LV twist measurement was possible in 39 of 50 individuals (78%). 2DSTE twist mean peak value was 13.8 + 7.9° with a mean time-to-peak of 388.3 ± 152.3 ms and global 3DSTE twist mean peak value was 10.2 + 7.6° with a mean time-to-peak of 371.8 ± 127.5 ms. Peak LV twist values by 3DSTE was significantly smaller than by 2DSTE (P < 0.01) whereas time-to-peak results showed no significant difference. 3DSTE is feasible to assess LV twist deformation. Whereas further investigations using 3DSTE are needed to validate this promising technology, comparing 2DSTE and 3DSTE should be done with caution, as values for peak LV twist differ.

Aerobic fitness does not influence the biventricular response to whole body passive heat stress

We examined biventricular function during passive heat stress in endurance trained (ET) and untrained (UT) men to evaluate whether aerobic fitness alters the volumetric response. Body temperature was elevated ~0.8°C above baseline in 20 healthy men (10 ET, 64.4 ± 3.0 ml·kg(-1)·min(-1); and 10 UT, 46.3 ± 6.2 ml·kg(-1)·min(-1)) by circulating warm water (50°C) throughout a tube-lined suit. Cardiac magnetic resonance imaging was used to measure biventricular volumes, function, filling velocities, volumetric flow rates, and left ventricular (LV) twist and circumferential strain at baseline (BL) and after 45 min of heat stress. In both groups, passive heat stress reduced biventricular end-diastolic (ET, -19.5 ± 24.0 ml; UT, -25.1 ± 23.8 ml) and end-systolic (ET, -15.9 ± 8.8 ml; UT, -17.6 ± 7.9 ml) volumes and left atrial volume (ET, -19.2 ± 11.6 ml; UT, -15.0 ± 12.7 ml) and significantly increased heart rate (ET, 29.3 ± 9.0 beats/min; UT, 31.7 ± 10.4 beats/min) and cardiac output (ET, 3.8 ± 2.2 l/min; UT, 3.2 ± 1.4 l/min) similarly, while biventricular stroke volume was unchanged. There were no between-group differences in any parameter. Heat stress increased (P < 0.05), as a percentage of baseline values, biventricular ejection fraction (ET, 3.4 ± 5.3%; UT, 4.4 ± 3.7%), annular systolic tissue velocities (ET, 32.5 ± 34.9%; UT, 44.0 ± 38.1%), and peak LV twist (ET, 51.6 ± 59.7%; UT, 59.7 ± 54.2%) and untwisting rates (ET, 45.5 ± 42.3%; UT, 51.8 ± 55.0%) similarly in both groups. Early LV diastolic tissue and blood velocities, volumetric flow rates, and strain rates (diastole) were unchanged with heat stress in both groups. The present findings indicate that aerobic fitness does not influence the biventricular response to passive heat stress.

Increased left ventricular twist, untwisting rates, and suction maintain global diastolic function during passive heat stress in humans

Left ventricular (LV) systolic function increases with passive heat stress (HS); however, less is known about diastolic function. Eight healthy subjects (24.0 +/- 2.0 yr of age) underwent whole body passive heating approximately 1 degrees C above baseline (BL). Cardiac magnetic resonance imaging was used to measure biventricular volumes, function, filling velocities, volumetric flow rates, and LV twist and strain at BL and after 45 min of HS. Passive heating reduced left atrial volume (-17.6 +/- 11.7 ml, P < 0.05), right and LV end-diastolic volumes (-22.7 +/- 11.0 and -25.7 +/- 24.9 ml, respectively; P < 0.05), and LV stroke volume (-6.7 +/- 6.8 ml, P < 0.05) from BL. LV ejection fraction (EF), end-systolic elastance, septal and lateral mitral annular systolic velocities, circumferential strain, and peak LV twist increased with HS (P < 0.05). Right ventricular stroke volume, EF, and systolic tissue velocities were unchanged with HS (P > 0.05). Early LV diastolic tissue and blood velocities and strain rates were maintained with HS, whereas untwisting rate increased significantly from 166.4 +/- 46.9 to 268.7 +/- 76.8 degrees /s (P < 0.05). The major novel finding of this study was that, secondary to an increase in peak LV twist and untwisting rate, early diastolic blood and tissue velocities and strain rates are maintained despite a reduction in filling pressure.

Effects of Cardiac Resynchronization Therapy on Left Ventricular Twist

This study explored the effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) twist, particularly in relation to LV lead position. LV twist is emerging as a comprehensive index of LV function. Eighty heart failure patients were included. Two-dimensional echocardiography was performed at baseline, immediately after CRT, and at 6-month follow-up. Speckle-tracking analysis was applied to assess LV twist. The LV lead was placed preferably in a (postero)lateral vein, and at fluoroscopy, the position was classified as basal, midventricular, or apical. Response to CRT was defined as reduction of LV end-systolic volume>or=15% at 6-month follow-up. A control group comprised 30 normal subjects. Peak LV twist in heart failure patients was 4.8+/-2.6 degrees compared with 15.0+/-3.6 degrees in the control subjects (p<0.001). At 6-month follow-up, peak LV twist significantly improved only in responders (56%), from 4.3+/-2.4 degrees to 8.5+/-3.2 degrees (p<0.001). The strongest predictor of response to CRT was the improvement of peak LV twist immediately after CRT (odds ratio: 1.899, 95% confidence interval: 1.334 to 2.703, p<0.001). Furthermore, LV twist significantly improved in patients with an apical (from 4.3+/-3.1 degrees to 8.6+/-3.0 degrees, p=0.001) and midventricular (from 4.8+/-2.2 degrees to 6.4+/-3.9 degrees, p=0.038) but not with a basal (5.0+/-3.3 degrees vs. 4.1+/-3.2 degrees, p=0.28) LV lead position. Similarly, LV ejection fraction significantly increased in patients with an apical (from 26+/-7% to 37+/-7%, p<0.001) and midventricular (from 26+/-6% to 33+/-8%, p<0.001) but not with a basal (26+/-5% vs. 28+/-8%, p=0.30) LV lead position. An immediate improvement of LV twist after CRT predicts LV reverse remodeling at 6-month follow-up.

Left Ventricular Rotational Mechanics in Acute Myocardial Infarction and in Chronic (Ischemic and Nonischemic) Heart Failure Patients

Left ventricular (LV) twist and untwisting rate are emerging as global and thorough parameters for assessment of LV function. This study explored differences of LV twist and untwisting rate in patients with acute myocardial infarction (AMI) and patients with ischemic and nonischemic chronic heart failure (HF). Fifty patients with AMI, 49 with ischemic HF, and 38 with nonischemic HF were studied. As a control group, 28 subjects without evidence of structural heart disease were included. Speckle-tracking analysis was applied to LV short-axis images at basal and apical levels. LV twist was defined as the net difference of apical and basal rotations at isochronal time points. The first time derivative of LV untwist was defined as the LV untwisting rate. Compared with control subjects, peak LV twist was decreased in patients with AMI and extremely decreased in those with HF (p <0.001, analysis of variance). A strong correlation (r = 0.87, p <0.001) was found between peak LV twist and LV ejection fraction in the overall study population. LV untwisting rate was progressively decreased in patients with AMI and HF compared with control subjects (p <0.001, analysis of variance). A moderate correlation (r = 0.56, p <0.001) was noted between peak LV untwisting rate and grade of diastolic dysfunction in the overall study population. In conclusion, LV twist and untwisting rate are strongly related to LV systolic and diastolic functions, respectively. Impairment of LV function observed in patients with AMI and HF is associated with a decrease of LV twist and untwisting rate.

Left Ventricular Torsion in Patients With Secundum Atrial Septal Defect

Recently, assessment of left ventricular (LV) torsional deformation has become an important approach for quantifying LV function. This study sought to evaluate LV torsion using speckle tracking imaging in patients with atrial septal defect (ASD). Basal and apical LV short-axis images were analyzed in 45 asymptomatic adults with isolated secundum ASD and 45 matched normal subjects. The apical rotation parameters were similar between 2 groups; however, the peak basal clockwise rotation was significantly depressed (-5.4 +/-2.8 degrees vs -6.9 +/-2.6 degrees , P<0.001) and time to the peak was significantly delayed (118.3 +/-18.8% vs 96.1 +/-12.6% of systolic period, P<0.001) in patients with ASD. The peak basal initial counterclockwise rotation in the ASD group was significantly higher (5.1 +/-3.3 degrees vs 1.8 +/-1.4 degrees , P<0.001) and longer (75.4 +/-26.7% vs 42.5 +/-24.4% of systolic period, P<0.001) than that in the control group. LV peak twist was also reduced significantly in patients with ASD (11.9 +/-5.9 degrees vs 14.6 +/-3.5 degrees , P<0.05) in comparison with the controls. LV systolic twist was significantly reduced in patients with ASD mainly because of the heterogeneous basal rotation.

Evaluation of left ventricular rotation and twist using speckle tracking imaging in patients with atrial septal defect

Speckle tracking imaging (STI) was employed to investigate the effect of right ventricular (RV) volume and pressure overload on left ventricular (LV) rotation and twist in 35 patients with atrial septal defect (ASD), 18 of which with pulmonary hypertension, and 21 healthy subjects serving as controls. The peak rotations of 6 segments at the basal and apical short-axises and the average peak rotation and interval time of the 6 segments in the opposite direction during early systolic phase were measured respectively. LV twist versus time profile was drawn and the peak twist and time to peak twist were calculated. LV ejection fraction (EF) was measured by Biplane Simpson. Compared to ASD patients without pulmonary hypertension and healthy subjects, the peak rotations of posterior, inferior and postsept walls at the basal level were lower (P<0.05), and the average counterclockwise peak rotation of 6 segments at the basal level during early systolic phase was higher (P<0.05), and the average interval time was delayed (P<0.05). LV peak twist was also lower (P<0.05), and had a significant negative correlation with pulmonary arterial systolic pressure (r=-0.57, P=0.001). No significant differences were found in LVEF among the three groups. It was suggested that although RV volume overload due to ASD has no significant effects on LV rotation and twist, LV peak twist is lower in ASD patients with pulmonary hypertension. Thus LV twist may serve as a new indicator of the presence of pulmonary hypertension in ASD patients.

Effect of Mechanical Dyssynchrony and Cardiac Resynchronization Therapy on Left Ventricular Rotational Mechanics

Alterations in rotational mechanics can bring new aspects to the understanding of left ventricular (LV) dyssynchrony. The aims of this study were to investigate LV rotational mechanics in candidates for cardiac resynchronization therapy (CRT) and to assess the effect of CRT by speckle-tracking echocardiography. Fifty-four patients with heart failure and 33 healthy controls were studied. Thirty-three underwent CRT. Speckle tracking was applied to short- and long-axis views. Radial and longitudinal dyssynchrony were assessed as previously defined. Apical and basal rotations were measured as the average angular displacement about the LV central axis. LV twist and torsion were then calculated. Peak apical and basal rotation, peak LV twist and torsion, apical and basal rotation at aortic valve closure (AVC), and LV twist and torsion at AVC were significantly lower in patients than controls. Apical-basal rotation delay and AVC-to-peak LV twist interval were longer in patients and associated with decreased peak LV twist and LV twist at AVC, respectively. In patients, rotational indexes, particularly LV twist and torsion, were correlated strongly with radial dyssynchrony. LV torsion (cutoff 0.1 degrees /cm) and twist (cutoff 1 degrees ) at AVC had the highest sensitivity (90%) and specificity (77%) to predict CRT responders among all other parameters, including radial and longitudinal dyssynchrony. In conclusion, LV dyssynchrony is associated with discoordinate rotation of the apical and basal regions, which in turn significantly decreases peak LV twist and torsion and LV twist and torsion at AVC. CRT significantly restored the altered rotational mechanics in responders. These parameters have potential for predicting responders to CRT.