Radial Left Ventricular Research Articles

Impaired Myocardial Radial Function in Asymptomatic Patients with Type 2 Diabetes Mellitus: A Speckle-Tracking Imaging Study

Diabetic cardiomyopathy has been characterized by an early impairment of left ventricular (LV) longitudinal function as opposed to preserved LV radial function. Conventional echocardiography and longitudinal (ε(L)) and radial (ε(R)) systolic strain assessed by speckle-tracking imaging were obtained in 114 type 2 diabetic patients and 88 age-matched controls. LV ejection fraction was similar in diabetic patients and controls. The presence of subclinical LV systolic dysfunction in diabetic patients was demonstrated by lower values of midwall fractional shortening (18% ± 3% vs 20% ± 3%, P = .006), ε(L) (-19% ± 3% vs -22% ± 2%, P < .001), and ε(R) (50% ± 16% vs 56% ± 12%, P = .003) compared with controls. On multivariate analysis, factors predicting strain values were diabetes (P = .001) and gender (P = .001) for ε(L) and diabetes (P = .003) for ε(R). Diabetic patients without overt heart disease display subclinical alteration of both radial and longitudinal LV systolic function even after adjustment for blood pressure, age, and body mass index.

Role of haemodialytic therapy on left ventricular mechanical dyssynchrony in patients with end-stage renal disease quantified by speckle-tracking strain imaging

Abnormal myocardial loading can contribute to left ventricular (LV) mechanical dyssynchrony in patients with end-stage renal disease (ESRD). The aims of this study were to characterize and quantify LV function and mechanical dyssynchrony in patients with ESRD, and to elucidate the impact of haemodialytic (HD) therapy on these parameters by speckle-tracking strain imaging. Twenty-three patients with ESRD (63 ± 11 years) before (pre-dialysis group) and after HD therapy (post-dialysis group) and 28 normal subjects (control group; 60 ± 10 years) were examined by echocardiography. Global and segmental LV peak systolic strain (PSS) were analysed, and LV mechanical dyssynchrony was assessed by calculating the standard deviation of the segmental time-to-PSS over longitudinal, circumferential or radial regions, respectively. Global PSS and LV ejection fraction in the pre-dialysis group were similar to those in the control group, and were not altered by HD therapy. LV mechanical dyssynchronies in the longitudinal and radial directions, but not in the circumferential direction, were significantly greater in the pre-dialysis group than those in the control group [longitudinal direction: 63 ± 15 (P < 0.05 vs. the control group) vs. 49 ± 15 ms, circumferential direction: 44 ± 24 vs. 41 ± 23 ms, and radial direction: 47 ± 29 (P < 0.05 vs. the control group) vs. 16 ± 18 ms]. HD therapy dramatically improved only the radial LV dyssynchrony in the post-dialysis group (23 ± 24 ms, P < 0.05 vs. the pre-dialysis group). The presence of ESRD was associated with longitudinal and radial LV dyssynchronies. In addition, HD therapy dramatically improved radial LV dyssynchrony, which strongly indicates that only radial LV dyssynchrony is preload dependent among the three LV systolic directions.

Evaluation of contractile function and inotropic reserve with tissue velocity, strain and strain rate imaging in streptozotocin-induced diabetes

The aim of the present study was to evaluate left ventricular (LV) function and contractile reserve (CR) with Doppler myocardial imaging (DMI) in a small animal model for type 1 diabetes. Cardiac function was assessed in anaesthetized Wistar rats 6 and 8 weeks after injection of 60 mg/kg of streptozotocin. At 6 weeks of diabetes, colour DMI echocardiography was performed at rest and during incremental dosages of dobutamine (5, 10, 20 microg/kg/min). Left ventricular fractional shortening was decreased after 8 weeks of follow-up [36 +/- 5 (D) vs. 41 +/- 4% (C); P = 0.049]. After 6 weeks of diabetes, DMI measurements were reduced in the diabetic rats in the inferolateral wall at rest [systolic velocity: 2.5 +/- 0.4 (D) vs. 4.4 +/- 0.3 (C) cm/s; P < 0.001; systolic strain rate: 12.2 +/- 3.4 (D) vs. 17.4 +/- 3.2 (C) 1/s; P = 0.012] and during inotropic stimulation [delta velocity (cm/s): 0.2 +/- 0.1 (D) vs. 0.5 +/- 0.3 (C)/5 microg dobutamine; P = 0.002; delta strain rate (1/s): 1.4 +/- 0.9 (D) vs. 3.3 +/- 2.2 (C)/5 microg dobutamine; P = 0.049]. Furthermore, the intraventricular delay in time-to-peak systolic strain was larger in diabetes [20 +/- 18 (D) vs. 10 +/- 7 (C) ms; P= 0.01]. Systolic mitral annular velocity was also lower in the diabetic rats at rest [2.7 +/- 0.4 (D) vs. 3.5 +/- 0.4 (C) cm/s; P < 0.001] and in response to dobutamine [delta velocity (cm/s): 0.1 +/- 0.1 (D) vs. 0.3 +/- 0.2 (C)/5 microg dobutamine; P = 0.013]. In experimental diabetes, a reduction in radial and longitudinal LV function and CR can be detected with DMI before the onset of a reduced global LV function.

Left ventricular twist mechanics in patients with apical hypertrophic cardiomyopathy: assessment with 2D speckle tracking echocardiography

Objective:Left ventricular (LV) apical rotation significantly contributes to LV twist, which has been reported to have a vital role in maintaining LV systolic and diastolic function. Apical hypertrophic cardiomyopathy (ApHCM)...

Impact of Right Ventricular Dilation on Left Ventricular Myocardial Deformation in Patients After Surgical Repair of Tetralogy of Fallot

Left ventricular (LV) dysfunction is 1 of the major determinants of late adverse clinical outcomes in patients after surgical repair of tetralogy of Fallot (TOF). The aim of this study was to test the hypothesis that LV myocardial deformation is impaired in patients after TOF repair and related to right ventricular (RV) dilation and exercise capacity. Longitudinal, radial, and circumferential LV myocardial deformation was determined using speckle-tracking echocardiography in 23 postoperative patients with TOF and compared to that of 23 age-matched controls. Relations between LV strain and strain rate (SR) and RV volumes and exercise parameters were determined in patients. Compared to controls, patients had reduced global LV longitudinal, radial, and circumferential strain (all p values <0.05). Patients with significantly increased RV end-systolic volume (>2 SDs higher than normal; n = 17) had reduced global LV circumferential strain (p = 0.048) and SR (p = 0.038), but similar longitudinal and radial speckle-tracking echocardiographic parameters, compared to those without (n = 6). RV end-systolic volume was correlated inversely with global LV circumferential strain and SR (r = -0.58, p = 0.004, and r = -0.58, p = 0.005, respectively), while RV end-diastolic volume was correlated only with global LV circumferential strain (r = -0.43, p = 0.047). In patients, the LV ejection fraction was correlated with global LV circumferential strain (r = 0.54, p = 0.01) and SR (r = 0.66, p = 0.001) but not with longitudinal or radial speckle-tracking echocardiographic parameters. Using multivariate analysis, global LV circumferential SR (beta = 0.66, p = 0.001) and male gender (beta = 0.46, p = 0.012) were identified as independent predictors of peak oxygen consumption. In conclusion, the negative impact of RV dilation on LV function relates to its influence on LV circumferential strain and SR in patients after TOF repair.

Strain analysis in patients with severe aortic stenosis and preserved left ventricular ejection fraction undergoing surgical valve replacement

To evaluate myocardial multidirectional strain and strain rate (S-and-SR) in severe aortic stenosis (AS) patients with preserved left ventricular (LV) ejection fraction (EF), using two-dimensional speckle-tracking strain imaging (2D-STI). The long-term effect of aortic valve replacement (AVR) on S-and-SR was also evaluated. Changes in LV radial, circumferential, and longitudinal S-and-SR were evaluated in 73 severe AS patients (65 +/- 13 years; aortic valve area 0.8 +/- 0.2 cm2) with preserved LVEF (61 +/- 11%), before and 17 months after AVR. Strain and strain rate data were compared with data from 40 controls (20 healthy individuals and 20 patients with LV hypertrophy) matched by age, gender, body surface area, and LVEF. Compared with controls, severe AS patients had significantly decreased values of LV S-and-SR in the radial (33.1 +/- 14.8%, P = 0.2; 1.7 +/- 0.5 s(-1), P = 0.003), circumferential (-15.2 +/- 5.0%, P = 0.001; -0.9 +/- 0.3 s(-1), P < 0.0001), and longitudinal (-14.6 +/- 4.1%, P < 0.0001; -0.8 +/- 0.2 s(-1), P < 0.0001) directions. At 17 months after AVR, LV S-and-SR significantly improved in all the three directions, whereas LVEF remained unchanged (60 +/- 12%, P = 0.7). In severe AS patients, impaired LV S-and-SR existed although LVEF was preserved. After AVR, a significant S-and-SR improvement in all the three directions was observed. These subtle changes in LV contractility can be detected by 2D-STI.

Left Ventricular Radial and Circumferential Wall Motion Analysis in Horses Using Strain, Strain Rate, and Displacement by 2D Speckle Tracking

Noninvasive assessment of left-ventricular (LV) function is clinically relevant, but is incompletely studied in horses. To document the feasibility, describe the techniques, and determine the reliability of 2D speckle tracking (2DST) for characterization of LV radial and circumferential wall motion in horses. Three Standardbreds, 3 Thoroughbreds; age 8-14 years; body weight 517-606 kg. Observational study. Repeated 2-dimensional echocardiographic examinations were performed in unsedated horses by 2 observers and subsequently analyzed by 2DST. Test reliability was determined for segmental and for averaged 2DST indices (including strain, strain rate, displacement, and rotation) by estimating measurement variability, within-day interobserver variability, between-day interobserver variability, and between-day intraobserver variability. Variability was expressed as coefficient of variation (percent) and the absolute value below which the difference between 2 measurements will lie with 95% probability. 2DST analyses were feasible in 16 of 18 echocardiographic studies. The automated tracking was accurate during systole but inaccurate during diastole. Reliability was higher for radial compared to circumferential measurements. For radial strain, radial systolic strain rate, and radial systolic displacement, the test-retest variabilities ranged between 2.4 and 33.1% for segmental and between 4.1 and 16.1% for averaged measurements. Systolic radial motion of the LV at the chordal level could be reliably characterized in horses by 2DST. Circumferential measurements were less reliable. Diastolic measurements were invalid because of inaccurate tracking. The clinical value of LV wall motion analysis by 2DST in horses requires further investigation.

Alteration in Left Ventricular Strains and Torsional Mechanics After Ultralong Duration Exercise in Athletes

Numerous studies have reported evidence of cardiac injury associated with transient left ventricular (LV) systolic and diastolic dysfunction after prolonged and strenuous exercise. We used 2D ultrasound speckle tracking imaging to evaluate the effect of an ultralong-duration exercise on LV regional strains and torsion. We speculated that systolic dysfunction after exercise is associated with depressed LV strains and torsion, and diastolic dysfunction results from decreased and delayed untwisting, a key factor of LV suction and early filling. Twenty-three triathletes underwent conventional and speckle tracking imaging echocardiography at rest before and immediately after an ultralong distance triathlon. Measurements included LV longitudinal, circumferential and radial strains, LV rotations, and LV torsion. After the race, LV systolic dysfunction was characterized by a decrease in LV longitudinal, radial, and circumferential strains, especially for apical radial strains (44.6+/-15.1% versus 31.1+/-13.8%, P<0.001). Peak torsion was slightly decreased (8.3+/-5.1 degrees versus 6.4+/-3.9 degrees , respectively, P=0.09) and significantly delayed (91+/-18% versus 128+/-31% of systolic duration, P<0.001) beside end-ejection. Peak untwisting was also depressed and delayed beside isovolumic relaxation. This study documented major alterations in cardiac strains and torsion after an ultralong distance triathlon. LV systolic strains were depressed but not delayed, whereas twisting was decreased and delayed. This altered pattern hampered the rapid untwisting during isovolumic relaxation phase, reducing LV diastolic suction and early filling.

Methods and Reliability of Tissue Doppler Imaging for Assessment of Left Ventricular Radial Wall Motion in Horses

Noninvasive assessment of left ventricular (LV) function is incompletely studied in horses. The goals of this study were to investigate the feasibility, techniques, and reliability of tissue Doppler imaging (TDI) for characterization of LV radial wall motion in healthy horses. Three Standardbreds, 3 Thoroughbreds; age 8-14 years; body weight 517-606 kg. Repeated echocardiographic examinations were performed by 2 observers in unsedated horses using TDI. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day interobserver and intraobserver variability of all echocardiographic variables. Variability was expressed as coefficient of variation (CV) and the absolute value below which the difference between 2 measurements will lie with 95% probability. Assessment of LV radial wall motion by TDI was feasible in all horses. Measurement variabilities were very low (CV < 5%) to low (CV 5-15%) for most variables. Within-day interobserver variability as well as between-day interobserver and intraobserver variabilities were low to moderate (CV 16-25%) for most variables. All pulsed-wave TDI variables of systolic LV function showed very low to low variability, whereas some of the variables of LV diastolic and LA function showed moderate to high (CV > 25%) variability. Pulsed-wave TDI variables appeared more reliable than color TDI variables. Measurement of TDI indices of LV function is feasible and reliable in adult Standardbred and Thoroughbred horses. The clinical relevance of LV function assessment by TDI remains to be determined.

Three-Dimensional-Wall Motion Tracking: A New and Faster Tool for Myocardial Strain Assessment: Comparison With Two-Dimensional-Wall Motion Tracking

Two-dimensional (2D) wall motion-tracking echocardiography (WMT) is a useful method to measure myocardial strain, but it is very limited because acquisition and analysis are time consuming. Three-dimensional (3D) WMT is a new method that might improve diagnostic usefulness and reduce study times. The aims of this study were to compare results on 2D and 3D WMT and to compare the times for the acquisition and analysis of regional myocardial strain between the two methods. Measurements of the radial and longitudinal strain of every left ventricular (LV) segment and the time for acquisition and analysis were obtained using 3D and 2D WMT. Thirty patients were enrolled (mean age, 57.2 +/- 19.6 years; 60% men). Three-dimensional WMT provided complete radial and longitudinal LV strain information, similar to 2D WMT (P = NS), but it was less time consuming: the times for acquisition and analysis were 14.0 +/- 1.9 minutes with 2D WMT and 5.1 +/- 1.1 minutes with 3D WMT (P < .001). Furthermore, in the same analysis, a greater number of segments could be analyzed using 3D WMT (72.4%) compared with 2D WMT (52.0%). Three-dimensional WMT provides a faster, more complete, and similar analysis to assess LV longitudinal and radial strain compared with 2D WMT. Thus, 3D WMT is a potential clinical bedside tool for quantifying myocardial strain.

Pulmonary Hypertension Affects Left Ventricular Basal Twist: A Novel Use for Speckle‐Tracking Imaging

Chronic pulmonary hypertension (PH) results in right ventricular (RV) mechanical dyssynchrony. However, its effects on left ventricular (LV) mechanics have not been examined. Since speckle-tracking echocardiography (STE) is a novel approach to quantify LV dyssynchrony; we decided to use STE to assess the effect of PH on LV mechanics. Our echocardiography database was queried for patients with PH who had undergone STE analysis and compared to similarly collected data from a group of healthy volunteers. Group I (15 patients, age of 53 +/- 17 years, pulmonary artery pressure of 62 +/- 20 mmHg, eccentricity index of 0.78 +/- 0.06, and LV ejection fraction of 64 +/- 11%) and Group II (8 healthy volunteers, age 41 +/- 9 years, pulmonary artery pressure 14.6 +/- 4.2 mmHg, eccentricity index of 1.02 +/- 0.05, and LV ejection fraction of 66 +/- 6 mmHg). There was no difference in QRS duration between the two groups. Although PH significantly altered basal LV twist (Group I: M =-5.76 degrees versus Group II: M =-1.82 degrees , P < 0.05), it had no effect on LV apical twist (5.29 degrees versus 4.50 degrees ; P = NS, respectively). More notably, significant LV radial basal LV dyssynchrony, measured as the time to peak LV basal twist, was seen as a result of PH. STE identifies the presence of LV dyssynchrony in PH despite normal LV ejection fraction and no difference in QRS duration. Additional studies are now required to further characterize these results and determine their prognostic significance.

Regional diastolic function by tissue Doppler echocardiography in systemic sclerosis: correlation with clinical variables

The incidence of left ventricular (LV) diastolic dysfunction is increased in systemic sclerosis (SSc), while systolic dysfunction is present in a small percentage of patients. The aim of this study was to asses the LV "regional" diastolic abnormalities in SSc patients by the mean of Doppler tissue imaging (DTI). Echocardiographic echo-Doppler (DE) and DTI parameters were analyzed for 67 SSc patients: abnormal E/A ratio at DE was detected in 24, while abnormal e/a at DTI was observed in 41. A significant prevalence of DTI diastolic abnormalities in the segments reflecting longitudinal versus those reflecting radial LV motion was found. The segments of the basal regions of LV myocardium were significantly more involved than those of the middle portion. Linear correlation was observed between the extent of the diastolic abnormalities and the duration of disease. Longitudinal myocardial systolic velocities were significantly reduced in patients with abnormal e/a DTI.

Progression of Left Ventricular Functional Abnormalities in Hypertensive Patients with Heart Failure: An Ultrasonic Two-Dimensional Speckle Tracking Study

Two-dimensional (2-D) strain imaging is a novel echocardiographic technique for myocardial function evaluation. We sought to investigate left ventricular (LV) systolic function in patients with heart failure caused by hypertension using a 2-D strain approach and to validate this method against Doppler strain measurements. The study population comprised 81 patients (66.4 +/- 7.4 years) with hypertension in New York Heart Association (NYHA) class I to IV and 20 healthy controls. Decreased longitudinal strain was demonstrated in the basal septal segment in NYHA I, in the basal and mid septal and basal lateral segments in NYHA II, and in all segments in NYHA III and IV. Radial and circumferential strain were reduced in patients with NYHA III and IV. Independent predictors of strain were duration of HT, LV mass index, LV end-diastolic volume index, and systolic blood pressure. The agreement between 2-D and Doppler strain remained within acceptable ranges (mean difference +/- 1 standard deviation: 0.61%-1.92% +/- 2.38%-2.92% for longitudinal strain in particular segments and 4.98% +/- 5.26% for radial strain). In hypertensive patients, (1) LV longitudinal systolic function progressively deteriorates from NYHA I to IV and abnormalities commence in the basal septum, (2) LV radial and circumferential systolic impairment appears in NYHA III and IV, and (3) 2-D strain measurement provides a feasible tool for the quantitation of LV systolic performance.

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.

Measures of Left Ventricular Dyssynchrony and the Correlation to Clinical and Echocardiographic Response After Cardiac Resynchronization Therapy

There is still no standardized measure of left ventricular (LV) dyssynchrony or definition of response in candidates of cardiac resynchronization therapy (CRT). Recipients of CRT underwent echocardiographic assessment of LV dyssynchrony before and immediately after implantation of a CRT device. Patients were followed for 6 months postimplantation. A total of 44 patients (64 +/- 12 years, 30 men, and 26 with ischemic cardiomyopathy) were included in this analysis. There was a significant decrease in both radial (304 +/- 137 vs 121 +/- 85 ms, p <0.001) and longitudinal (143 +/- 104 vs 95 +/- 43 ms, p = 0.02) measures of LV dyssynchrony immediately after CRT. The immediate post-CRT change in radial (r = -0.43, p = 0.015) but not longitudinal (r = -0.09, p = 0.61) LV dyssynchrony correlated with a significant improvement in the physical component of the quality-of-life score 6 months after CRT. Although a higher baseline longitudinal (p = 0.05) or radial (p = 0.025) LV dyssynchrony predicted a >or=1 improvement in New York Heart Association classification of heart failure 6 months after CRT, acute changes in neither radial (p = 0.71) nor longitudinal (p = 0.89) LV dyssynchrony were predictive of any improved echocardiographic outcomes in follow-up. Concordance between clinical and echocardiographic response to CRT was documented in 72% of patients. In conclusion, both longitudinal and radial measures of LV dyssynchrony improve after CRT. The change in longitudinal but not radial measures of LV dyssynchrony correlates with improved physical quality-of-life score in intermediate term follow-up.

Asynchronous normal regional left ventricular function assessed by speckle tracking echocardiography: Appearances can be deceptive

Background Speckle tracking echocardiography (STE) is an angle independent method with high temporal resolution, which offers quantification of regional left ventricular (LV) wall motion. We studied radial and longitudinal LV wall motion by STE in healthy subjects with normal wall motion analysis (WMA) by eye-balling. Materials and methods Eighteen healthy subjects were studied. We acquired parasternal short and apical long axis projections to determine the basal, mid and apical radial and longitudinal functions. At each level we measured; (I) radial and longitudinal peak displacement and displacement at aortic valve closure (AVC) and (II) the time interval from the Q-wave to the AVC and peak displacement. Results WMA indicated normal wall motion in all subjects. The mean peak radial displacement varied in different segments (range 3.9–9.8 mm) with highest values in the mid-level (6.9 ± 1.5 mm), compared to basal level (5.9 ± 1.0 mm, p < 0.01) and apical level (5.4 ± 1.0 mm, p < 0.001). The time from Q-wave to AVC was 393 ms and in 89% of the analysed segments peak radial displacement occurred after AVC, thus mean peak radial displacement occurred 60 ms after AVC. The peak longitudinal amplitude was more synchronous with respect to AVC and with the highest amplitudes found in the two basal segments. Conclusions In normal LV function, significant differences in peak displacement exist between segments at various LV levels using STE. In addition, in early diastole, significant discrepancy occurs between radial and longitudinal time of peak displacement, suggesting a shape change. Finally, while radial displacement was highest at mid-cavity level longitudinal displacement was highest at basal level.

Noninvasive Assessment of Systolic Left Ventricular Torsion by 2‐Dimensional Speckle Tracking Imaging in the Awake Dog: Repeatability, Reproducibility, and Comparison with Tissue Doppler Imaging Variables

Left ventricular (LV) torsional deformation plays an important role in myocardial function. However, it has never been assessed in the awake dog, because magnetic resonance imaging and sonomicrometry have been the only methods available so far. Two dimensional speckle tracking echocardiography (STE), a new ultrasound imaging technique, provides a repeatable and reproducible noninvasive assessment of systolic LV wringing motion in the awake dog. Six healthy dogs were used to determine the repeatability and reproducibility of STE variables (study 1). These variables also were prospectively assessed in a population of 35 healthy dogs (study 2). Peak LV basal and apical systolic rotations were measured by STE from right parasternal short-axis views using automatic frame-to-frame tracking of gray-scale speckle patterns. Systolic LV torsion (LVtor, degrees ) was defined as apical rotation relative to the base. All within-day and between-day coefficients of variation were <20% (6.8-18.0%). Amplitude of apical systolic rotation was significantly higher (P < .001) than the basal value (5.4 +/- 3.2 degrees and -3.1 +/- 1.3 degrees , respectively). Global LVtor was significantly correlated with systolic longitudinal LV myocardial velocity gradient assessed by tissue Doppler (P < .05), but not with either systolic radial LV myocardial velocity gradient or the ratio of early mitral inflow velocity to early mitral annular velocity (Em/Ea). Speckle tracking echocardiography is a repeatable and reproducible method for assessing systolic LV torsional deformation. The combination of these new STE indices with tissue Doppler variables could provide a new approach for quantifying canine LV systolic function.

Stiffness- and relaxation-based quantitation of radial left ventricular oscillations: elucidation of regional diastolic function mechanisms

Traditionally, global and longitudinal (i.e., regional) left ventricular (LV) diastolic function (DF) assessment has utilized features of transmitral Doppler E and A waves or Doppler tissue imaging (DTI)-derived mitral annular E' and A' waves, respectively. Quantitation of regional DF has included M-mode echocardiography-based approaches and strain and strain rate imaging (in selected imaging planes), while analysis of mitral annular "oscillations" has recently provided a new window into longitudinal (long-axis) function. The remaining major spatial degree of kinematic freedom during diastole, radial (short-axis) motion, has not been fully characterized, nor has it been exploited for its potential to provide radial LV stiffness (k'(rad)) and relaxation/damping (c'(rad)) indexes. Prior characterization of regional (longitudinal) DF used only annular E'- and A'-wave peak velocities or, alternatively, myocardial strain and strain rate. By kinematically modeling short-axis tissue motion as damped radial oscillation, we present a novel method of estimating k'(rad) and c'(rad) during early filling. As required by the (near) constant-volume property of the heart and tissue/blood incompressibility, in subjects (n = 10) with normal DF, we show that oscillation duration-determined longitudinal (k'(long) and c'(long)) and radial (k'(long) and c'(rad)) parameters are highly correlated (R = 0.69 and 0.92, respectively). Selected examples of diabetic and LV hypertrophic subjects yield radial (k'(long) and c'(rad)) parameters that differ substantially from controls. Results underscore the utility of the incompressibility-based causal relation between DTI-determined mitral annular long-axis (longitudinal mode) and short-axis (radial mode) oscillations in healthy subjects. Selected pathological examples provide mechanistic insight and illustrate the value and potential role of regional (longitudinal and radial) DF indexes in fully characterizing normal vs. impaired DF states.

Early myocardial abnormalities in asymptomatic patients with severe isolated congenital aortic regurgitation: An ultrasound tissue characterization and strain rate study

Aortic valve regurgitation (AR) in the pediatric population has increased in recent years because of the expanded use of new surgical and hemodynamic procedures. Unlike adult patients, few predictors for the need of operation have been proposed in young asymptomatic or mildly symptomatic patients with AR. To unmask early abnormalities of left ventricular (LV) function, 59 participants were enrolled: 14 asymptomatic patients (mean age 18 years) with congenital isolated severe AR and normal LV function (LV ejection fraction > 50%); and 45 healthy control subjects with comparable age and body surface area. All the studied population underwent standard echocardiographic examination, integrated backscatter, and strain rate imaging study. Conventional echocardiographic indices of global LV systolic performance for patients with AR were similar to that of control subjects. Compared with control subjects, integrated backscatter analysis demonstrated a significant reduction in cyclic variation in both septal and posterior walls ( P < .05). LV radial and longitudinal deformation properties for patients with AR were significantly reduced ( P < .05) as assessed by peak systolic strain rate. Our results demonstrated the ability of integrated backscatter and strain rate imaging to detect early subclinical abnormalities in young patients with severe congenital AR despite the presence of a normal ejection fraction.