Prognostic implications of left ventricular dyssynchrony early after non-ST elevation myocardial infarction without congestive heart failure.

AIMS: To determine independent predictors of left ventricular (LV) dyssynchrony after non-ST elevation myocardial infarction (NSTEMI) and prognostic value of combining dyssynchrony parameters for long-term LV dysfunction. METHODS AND RESULTS: Left ventricular dyssynchrony assessments were performed in 100 NSTEMI patients followed-up for 1 year using a composite dyssynchrony score. Early LV dyssynchrony was independently predicted by the presence of significant proximal left circumflex artery (LCx) stenosis and global systolic dysfunction. Left ventricular end-diastolic volume index decreased with time and was independently determined by a lower number of diseased vessels and the absence of early dyssynchrony. Left ventricular end-systolic volume index decreased with time and was independently determined by the absence of early dyssynchrony, lower number of diseased vessels, and revascularization. Left ventricular ejection fraction increased with time and was independently determined by the absence of early dyssynchrony, lower number of diseased vessels, and revascularization. The composite dyssynchrony score was an independent determinant of a persistently dilated LV and low LVEF at follow-up. CONCLUSION: After NSTEMI, proximal LCx stenosis and impaired LV function independently predicted LV dyssynchrony. The composite dyssynchrony score had prognostic value and identified patients with persistently dilated and impaired LV on follow-up.

Incremental value of 2-dimensional speckle tracking strain imaging to wall motion analysis for detection of coronary artery disease in patients undergoing dobutamine stress echocardiography.

BACKGROUND: Interpretation of dobutamine stress echocardiogram (DSE) is often subjective and requires expert training. The purposes of this study was to determine optimal cutoff values for longitudinal, circumferential, and radial strains at peak DSE for detection of significant stenoses on coronary angiography and to investigate incremental value of combining strain measurements to wall motion analysis. METHODS: In this multicenter study, 102 patients underwent concomitant DSE and coronary angiography. Optimal cutoff values for mean global longitudinal (-20%), global circumferential (-26%), and mean radial (50%) strains at peak stress for detection of significant stenoses on coronary angiography were determined in a derivation group (n = 62) and tested in a prospectively recruited validation group (n = 40). RESULTS: Respective sensitivities for longitudinal, circumferential, radial strains, and expert wall motion score index (WMSI) were 84.2%, 73.9%, 78.3%, and 76%; respective specificities were 87.5%, 78.6%, 57.1%, and 92.9%; and respective accuracies were 85.2%, 75.7%, 70.3%, and 82.1%. Longitudinal strain analysis had comparable accuracy to WMSI (P = .70). However, combination longitudinal strain and WMSI had the highest sensitivity, specificity, and accuracy (100%, 87.5%, and 96.3% respectively), and its diagnostic accuracy was incremental to either longitudinal strain (P = .034) or WMSI alone (P = .008). CONCLUSION: Longitudinal strain analysis had higher diagnostic accuracy than circumferential and radial strains and was comparable to WMSI for detection of significant coronary artery disease. However, combination longitudinal strain and WMSI resulted in significant incremental increase in diagnostic accuracy.

Comparison of myocardial tissue velocities measured by two-dimensional speckle tracking and tissue Doppler imaging.

Myocardial velocities have prognostic implications, and transmitral E wave to mitral annular early diastolic tissue velocity ratio (E/Em) is utilized to estimate left ventricular (LV) end-diastolic pressure (EDP). There are no reference values for 2-dimensional (2D) speckle tracking myocardial velocities (S2D, E2D, A2D), and it is unknown if they are comparable with color tissue Doppler imaging (TDI). Predictors of E/E2D ratios are unknown and E/E2D has not been validated with LVEDP. The myocardial velocities of 142 subjects were measured by TDI and 2D speckle tracking. Mean E/Em and E/E2D were calculated as transmitral E wave to mean 6 basal early diastolic myocardial velocities using TDI and 2D speckle tracking respectively, and compared with LVEDP during catheterizations (n = 20). Mean E2D was lower but mean S2D and A2D were higher than TDI (all p <0.001). When TDI sample volume was tracked throughout the cardiac cycle, this directional difference was no longer apparent with S2D, E2D, and A2D higher than TDI (all p <0.05). Age, systolic blood pressure, LV ejection fraction, and mean S2D were independent correlates of E/E2D. Receiver-operator characteristic analysis showed E/E2D (p = 0.03), not E/Em, identified elevated LVEDP (> or =12 mm Hg). E/E2D of 11.6 had 83% sensitivity and 70% specificity to predict elevated LVEDP. In conclusion, TDI and 2D speckle tracking myocardial velocities are not comparable due to angle independency and ability for tissue tracking with the latter. LV systolic function, age, and afterload are independent correlates of E/E2D. Only E/E2D identifies elevated LVEDP, and an E/E2D of 11.6 has the optimal sensitivity and specificity.

Changes in Right Ventricular Function with Exercise in Healthy Subjects: Optimal Parameters and Effects of Gender and Age.

BACKGROUND: Right ventricular (RV) function augments with exercise, and loss of this adaptive ability often determines symptoms. Reports on exercise-related changes in RV function in healthy subjects are sparse. In this study, healthy volunteers were prospectively recruited, and changes in RV function with exercise were examined, optimal parameters determined, and the effects of gender and age examined. METHODS: Treadmill exercise stress echocardiography with concurrent expired gas analysis was performed in 121 healthy volunteers. Parameters of RV systolic function (RV fractional area change, Doppler tissue s' velocity, and systolic strain and strain rate) and diastolic function (peak E and A velocity, Doppler tissue e', a' and early and late diastolic strain rate) were evaluated at baseline and after exercise, with the difference (Δ) being systolic and diastolic reserve. Changes in pulmonary arterial pressure (PAP) was measured when accurate estimation was possible. RESULTS: Most systolic functional parameters were augmented with exercise. However, systolic augmentation decreased with age (Δs': r = -0.31, P < .01; Δ strain: r = -0.28, P = .008; Δ systolic strain rate: r = -0.31, P < .01). Similar changes were observed with diastolic function (Δe': r = -0.33, P < .01; Δ early diastolic strain rate r = -0.20, P = .04). In the subgroup with PAP measurements, ΔPAP (r = 0.32, P < .01) increased with age. Men had greater augmentation of systolic reserve, but differences were negated when corrected for workload. S' velocity was the most robust measure of RV systolic function. CONCLUSIONS: There is a modest yet significant reduction in RV systolic and diastolic reserve with age, with an increase in PAP. S' velocity is a robust and feasible measure that should be considered given the increasing use of stress testing to evaluate RV function.

Effects of age and gender on right ventricular systolic and diastolic function using two-dimensional speckle-tracking strain.

BACKGROUND: Accurate assessment of the right ventricle is increasingly important. Measures of right ventricular (RV) systolic function, including fractional area change, tissue Doppler (s' velocity), and tricuspid annular plane systolic excursion, show significant variation, and the impacts of age and gender are unclear. The aim of this study was to determine the effects of gender and age on global and segmental RV systolic and diastolic function using both traditional echocardiographic and two-dimensional strain parameters. METHODS: Detailed transthoracic echocardiographic studies were performed on 142 healthy adult volunteers, with particular emphasis on the right ventricle to determine RV dimensions and function, including fractional area change, tricuspid annular plane systolic excursion, s' velocity, global and segmental systolic strain, and systolic, early diastolic, and late diastolic strain rates. RESULTS: Tricuspid annular plane systolic excursion (r = -0.4, P < .001) and RV s' velocity (r = -0.5, P < .001) as well as diastolic functional parameters, including transtricuspid peak E velocity and RV free wall e' velocity (r = -0.4, P < .001), decreased with age. Global systolic strain was also reduced, with differential reductions in basal and mid segmental strain with age. Early diastolic strain rate decreased, with a corresponding increase in late diastolic strain rate. RV function parameters, including fractional area change, e' velocity, strain, and strain rate, were significantly lower in men. CONCLUSIONS: RV functional analysis by two-dimensional strain demonstrates a small yet significant change in global and segmental RV function with age and gender, and therefore adjustment for these measures is required in the evaluation of RV function.

Long-term impact of right ventricular septal versus apical pacing on left ventricular synchrony and function in patients with second- or third-degree heart block.

Right ventricular (RV) septal pacing has been advocated as an alternative to apical pacing to avoid long-term detrimental effects. There is conflicting evidence on the benefits of RV septal pacing. Fifty-five subjects (22 normal healthy controls, 17 with RV septal pacing, and 17 with apical pacing) were recruited. Midventricular short-axis left ventricular (LV) circumferential and radial strains were determined. Circumferential and radial strain dyssynchrony and longitudinal systolic dyssynchrony were determined. Echocardiographic determination of pacing sites were compared with electrocardiogram and chest x-ray. Septal pacing is a heterogenous group of different pacing sites, and there was only modest agreement among echocardiogram, electrocardiogram, and chest x-ray. Median pacing durations were 436 days for septal pacing and 2,398 days for apical pacing. Mean QRS duration for apical pacing was longest, followed by septal pacing and control (p <0.001). LV mass index, end-systolic volume index, and ejection fraction were more impaired in septal than in apical pacing (all p values <0.05). Septal pacing was associated with more impaired circumferential strain (p <0.001) and worse LV dyssynchrony than apical pacing and control. In conclusion, standard fluoroscopic and electrocardiographic implantation techniques for RV septal pacing resulted in a heterogenous group of different pacing sites. This heterogenous RV septal pacing group was associated with poorer long-term LV function and greater dyssynchrony than RV apical pacing and control.

Comparison of left ventricular dyssynchrony by two-dimensional speckle tracking versus tissue Doppler imaging in patients with non-ST-elevation myocardial infarction and preserved left ventricular systolic function.

Assessment of left ventricular (LV) dyssynchrony after myocardial infarction has prognostic value. There were no reference ranges for 2-dimensional (2D) speckle tracking synchrony, and it was unclear whether color tissue Doppler imaging and 2D speckle tracking synchrony indexes were comparable. One hundred twenty-two healthy volunteers and 40 patients with non-ST-elevation myocardial infarction (NSTEMI) had LV systolic and diastolic synchrony, defined as the SD of time to peak systolic (2D-SDTs) and early diastolic (2D-SDTe) velocities in the 12 basal and mid segments using 2D speckle tracking, respectively. Mean 2D-SDTs and 2D-SDTe were 29.4 +/- 16.1 and 14.2 +/- 6.1 ms in healthy subjects, respectively. Gender and mean 2D systolic velocity independently predicted 2D-SDTs, and mean 2D early diastolic velocity independently predicted 2D-SDTe. Bland-Altman analysis showed suboptimal agreement between 2D speckle tracking and tissue Doppler imaging dyssynchrony indexes. 2D speckle tracking showed lower coefficients of variation for time to peak systolic and early diastolic velocities than tissue Doppler imaging. There were no significant differences in coefficients of variation for 2D speckle tracking systolic and diastolic synchrony for high versus low frame rates. Patients with NSTEMI had significantly lower ejection fraction, but higher LV mass and wall stress than healthy subjects. Only 2D-SDTs was significantly higher in patients with NSTEMI compared with healthy subjects (37.1 +/- 22.5 vs 29.4 +/- 16.1 ms; p = 0.02). In conclusion, 2D-SDTs was gender specific and influenced by global systolic function, and 2D-SDTe was influenced by global diastolic function. 2D speckle tracking and tissue Doppler imaging dyssynchrony indexes were not comparable. 2D speckle tracking may be a more sensitive discriminator of LV systolic dyssynchrony than tissue Doppler imaging.

Left ventricular longitudinal and radial synchrony and their determinants in healthy subjects.

OBJECTIVE: The reference values and impact of physiologic variables on echocardiographic quantification of left ventricular (LV) synchrony in a large series of healthy persons are unknown. This study prospectively investigated the impact of age, gender, and other physiologic parameters on LV longitudinal and radial synchrony. METHODS: LV longitudinal systolic and diastolic synchrony using tissue Doppler imaging were measured as the standard deviation of times to 12 regional peak myocardial systolic Sm (SDTs) and early diastolic Em (SDTe) velocities in 122 healthy volunteers (age 19-68 years, 64 men). By using 2-dimensional speckle tracking, radial synchrony was measured as the standard deviation of times to 6 regional peak strain (SDTrepsilon) in the short-axis papillary muscle level. Longitudinal systolic synchrony was also measured as the standard deviation of times to 12 regional peak strain (SDTlepsilon). RESULTS: The mean QRS duration and LV ejection fraction were 87 +/- 12 msec and 61% +/- 5.5%, respectively. The mean SDTs and SDTe were 37.1 +/- 17.4 msec and 17.3 +/- 6.7 msec, respectively. Gender and the mean Sm velocity from the 6 basal LV segments were independent predictors of SDTs, whereas the isovolumic relaxation time and mean Em velocity independently predicted SDTe. The mean SDTrepsilon was 19.2 +/- 14.6 msec. SDTrepsilon did not correlate with any clinical or echocardiographic parameters. The mean SDTlepsilon was 40.4 +/- 11.8 msec. Isovolumic relaxation time, pulmonary S/D ratio, and mean Sm independently predicted SDTlepsilon. There was no correlation between LV longitudinal and radial synchrony. Intraobserver and interobserver variability analyses showed the highest correlation for SDTs compared with SDTrepsilon and SDTlepsilon. CONCLUSION: This study establishes normal reference ranges for LV systolic and diastolic synchrony measured with tissue Doppler velocity-based and 2-dimensional speckle tracking-based methods in a large group of healthy subjects of both genders across a wide age group. SDTs is gender specific and dependent on global LV systolic function, whereas SDTe is dependent on global LV diastolic function. Two-dimensional speckle-derived radial synchrony is independent of any clinical and echocardiographic variables but has higher intraobserver and interobserver variability compared with SDTs. LV longitudinal synchrony does not correlate with radial synchrony.