Non-invasive Left Ventricular Pressure-strain Loop Research Articles

Association between epicardial adipose tissue and myocardial work by non-invasive left ventricular pressure-strain loop in people with suspected metabolic syndrome

Given the inconsistent results on the prognostic significance of epicardial adipose tissue (EAT), the purpose of the present study was to investigate the association of EAT thickness and myocardial work by non-invasive left ventricular pressure-strain loop in people with suspected metabolic syndrome (MS). A total of 194 participants imaged with echocardiography were evaluated. In accordance with the median EAT thickness, MS patients fell into thin EAT group and thick EAT group. Conventional echocardiographic parameters, global longitudinal strain (GLS) and the global myocardial work parameters obtained by pressure-strain loop analysis, comprising the global work index (GWI), global work efficiency (GWE), global constructive work (GCW) and global wasted work (GWW) were compared between the two groups. In comparison with the thin EAT group, thick EAT group achieved significantly higher values in interventricular septal thickness, end-diastolic left ventricular posterior wall thickness, left ventricular mass index and GWW (p < 0.05). while the absolute value of GLS, GWI, GCW, and GWE were notably lower in the thick EAT group (p < 0.001). EAT thickness showed a significant correlation with GWI and GCW (r = − 0.328, p = 0.001; r = − 0.253, p = 0.012), and also independently correlated with GWI and GCW in the multivariate regression analysis (β = − 0.310, p = 0.001; β = − 0.199, p = 0.049). EAT thickness is associated with left ventricular myocardial function in subjects with suspected metabolic syndrome, independently of other risk factors. Further studies are supposed to ensure the causal associations and related mechanisms.

Correlation analysis between myocardial work indices and liver function classification in patients with hepatitis B cirrhosis: A study with non-invasive left ventricular pressure-strain loop.

Liver cirrhosis is closely associated with cardiac dysfunction. The aims of this study were to evaluate left ventricular systolic function in patients with hepatitis B cirrhosis by non-invasive left ventricular pressure-strain loop (LVPSL) technique, and to explore the correlation between myocardial work indices and liver function classification. According to the Child-Pugh classification, 90 patients with hepatitis B cirrhosis were further divided into three groups: Child-Pugh A group (n = 32), Child-Pugh B group (n = 31), and Child-Pugh C group (n = 27). During the same period, 30 healthy volunteers were recruited as the control (CON) group. Myocardial work parameters, which included global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), were derived from the LVPSL and compared among the four groups. The correlation between myocardial work parameters and Child-Pugh liver function classification was evaluated, and the independent risk factors affecting left ventricular myocardial work in patients with cirrhosis were investigated by univariable and multivariable linear regression analysis. GWI, GCW and GWE of Child-Pugh B and C groups were lower than those of CON group, while GWW was higher than that of CON group, and the changes were more obvious in Child-Pugh C group (P < 0.05). Correlation analysis revealed that GWI, GCW, and GWE were negatively correlated with liver function classification to various degrees (r = -0.54, -0.57, and -0.83, respectively, all P < 0.001), while GWW was positively correlated with liver function classification (r = 0.76, P < 0.001). Multivariable linear regression analysis showed that GWE was positively correlated with ALB (β = 0.17, P < 0.001), and negatively correlated with GLS (β = -0.24, P < 0.001). The changes in the left ventricular systolic function in patients with hepatitis B cirrhosis were identified using non-invasive LVPSL technology, and myocardial work parameters are significantly correlated with liver function classification. This technique may provide a new method for the evaluation of cardiac function in patients with cirrhosis.

Global Left Ventricular Myocardial Work Efficiency in Patients With Severe Rheumatic Mitral Stenosis and Preserved Left Ventricular Ejection Fraction.

Assessment of left ventricular (LV) function plays a pivotal role in the management of patients with valvular heart disease, including those caused by rheumatic heart disease. Noninvasive LV pressure-strain loop analysis is emerging as a new echocardiographic method to evaluate global LV systolic function, integrating longitudinal strain by speckle-tracking analysis and noninvasively measured blood pressure to estimate myocardial work. The aim of this study was to characterize global LV myocardial work efficiency in patients with severe rheumatic mitral stenosis (MS) with preserved ejection fraction (EF). We retrospectively included adult patients with severe rheumatic MS with preserved EF (> 50%) and sinus rhythm. Healthy individuals without structural heart disease were included as a control group. Global LV myocardial work efficiency was estimated with a proprietary algorithm from speckle-tracking strain analyses, as well as noninvasive blood pressure measurements. A total of 45 individuals with isolated severe rheumatic MS with sinus rhythm and 45 healthy individuals were included. In healthy individuals without structural heart disease, the mean global LV myocardial work efficiency was 96% (standard deviation [SD], 2), Compared with healthy individuals, median global LV myocardial work efficiency was significantly worse in MS patients (89%; SD, 4; p < 0.001) although the LVEF was similar. Individuals with isolated severe rheumatic MS and preserved EF, had global LV myocardial work efficiencies lower than normal controls.

783 RELATIONSHIP BETWEEN PULSE WAVE VELOCITY AND MYOCARDIAL WORK IN UNTREATED HYPERTENSIVE PATIENTS WITH PRESERVED LVEF

Abstract Introduction Hemodynamic interaction between left ventricular (LV) and arterial system is a key determinant of cardiovascular performance. The non-invasive carotid-femoral Pulse Wave Velocity (PWV), obtained with applanation tonometry, is considered the most precise way of estimating arterial stiffness. The LV myocardial work (MW), based on non-invasive LV pressure-strain loop (PSL), is a new promising tool to assess LV function. Aims The aim of the study was to evaluate the correlation between PWV and MW parameters in a population of non-hypertensive and newly diagnosed untreated hypertensive people. Materials and methods 80 people (M=48), divided in hypertensive (group 1 n=40, 45±10 years) and non-hypertensive (group 2 n=40, 40±12 years), were prospectively enrolled. All underwent conventional transthoracic echocardiogram and at the same day carotid femoral PWV was calculated with applanation tonometry (SphygmoCor® XCEL). MW parameters were obtained using 2D Speckle-tracking technique. Results Comparing the two groups, PWV and Global Work Wasted (GWW) were significantly higher in the hypertensives group (9,73±2,4 vs 7,79±1,1; p=0,001 and 146±50 vs 85±27, p=0,001), as shown in Figure 1, whereas Global Work Efficiency (GWE) and Global Work Constructive (GWC) were significantly lower (93,6±2,5 vs 95,6±1,2, p=0,001 and 2410±122 vs 2167±65, p=0,002). We found a linear and positive correlation of PWV with GWW (r=0,271, p=0,016), as seen in Figure 2, and a linear and negative correlation of PWV with GWE (r=-0,282, p=0,012). Conclusion This study highlights the role of PWV and MW evaluation in hypertensives. Higher PWV and GWW could be considered as red flags of myocardial damage suggesting the need of an early appropriate antihypertensive therapy.

Relationship between Pulse Wave Velocity and Myocardial Work in untreated hypertensive patients with preserved LVEF

Abstract Introduction Hemodynamic interaction between left ventricular (LV) and arterial system is a key determinant of cardiovascular performance. The non-invasive carotid-femoral Pulse Wave Velocity (PWV), obtained with applanation tonometry, is considered the most precise way of estimating arterial stiffness. The LV myocardial work (MW), based on non-invasive LV pressure-strain loop (PSL), is a new promising tool to assess LV function. Purpose The aim of the study was to evaluate the correlation between PWV and MW parameters in a population of non-hypertensive and newly diagnosed untreated hypertensive people. Material and methods 50 people (M=30), divided in hypertensive (group 1: n=25, 40±8 years) and non-hypertensive (group 2: n=25, 38±9 years), were prospectively enrolled. All underwent conventional transthoracic echocardiography and at the same day carotid femoral PWV was calculated with applanation tonometry (SphygmoCor® XCEL). MW parameters were obtained using 2D Speckle-tracking technique. Results Comparing the two groups, PWV and Global Work Wasted (GWW) were significantly higher in the hypertensives group (9.44±2.4 vs 7.56±1.1; p=0.001 and 130±2.5 vs 80.60±1.5, p=0.002), as shown in Figure 1, whereas Global Work Efficiency (GWE) and Global Work Constructive (GWC) were significantly lower (94±2.5 vs 95.8±1.2, p=0.003 and 2393±20 vs 2166±18, p=0.02). We found a linear and positive correlation of PWV with GWW (r=0.315, p=0.026), as seen in Figure 2, and a linear and negative correlation of PWV with GWE (r=−0.315, p=0.026). Conclusion This study highlights the role of PWV and MW evaluation in hypertensives. Higher PWV and GWW could be considered as red flags of myocardial damage suggesting the need of an early appropriate antihypertensive therapy. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): University Ospital G. Martino - Messina

Assessment of Myocardial Work of the Left Ventricle before and after PCI in Patients with Non-ST-Segment Elevation Acute Coronary Syndrome by Pressure-Strain Loop Technology.

Objectives Noninvasive left ventricular pressure-strain loop (PSL) is a new method for quantitative evaluation of myocardial work, which is developed on the basis of speckle tracking echocardiography. It is necessary to fit the noninvasive left ventricular pressure and the strain by speckle tracking echocardiography to construct a pressure-strain loop. Compared with traditional left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS), it has potential application value and is a useful supplement for clinical evaluation of left ventricular systolic function. We perform this study to evaluate the changes of myocardial function in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) before and after percutaneous coronary intervention (PCI) with noninvasive left ventricular pressure-strain loop (PSL). Methods 33 NSTE-ACS patients admitted to the Department of Cardiovascular Medicine of the Affiliated Lianyungang Hospital of Xuzhou Medical University who successfully underwent early PCI were included as the PCI group. At the same time, 30 healthy patients matched in age and sex were selected as the control group. All patients received routine echocardiography. The parameters such as GWI, GCW, GWW, and GWE were obtained by EchoPAC 203 software. The differences in the general clinical data and echocardiographic parameters between the two groups, including controls and patients 1 day before surgery and 1 month after surgery, were compared. Results Compared with the control group, GWI, GCW, and GWI in the PCI group were decreased 1 day before surgery and 1 month after surgery, while GWW was increased, with statistical significance (P < 0.05). In the PCI group, compared with 1 day before surgery, GWI and GCW were all increased 1 month after surgery (P < 0.05), and GWW and GWE were not significantly different between the two groups (P > 0.05). Conclusion The noninvasive left ventricular PSL technology can early and accurately evaluate the myocardial function impairment in NSTE-ACS patients and the recovery of myocardial function after PCI, providing a new noninvasive method for clinical postoperative myocardial function evaluation.

Noninvasive Evaluation of Myocardial Work in Patients with Chronic Kidney Disease Using Left Ventricular Pressure-Strain Loop Analysis.

(1) Objective: To evaluate myocardial injury by observing the different parameters of global myocardial work (MW) by left ventricular pressure-strain loop (PSL) analysis in patients with chronic kidney disease (CKD). (2) Methods: According to the left ventricular mass index, the study patients with CKD were further divided into two groups: the left ventricular normal group (CKDN-LVH, 59) and left ventricular hypertrophy group (CKDLVH, 46). Thirty-three healthy controls (CON) matched in age and sex with the CKD group were recruited. The routine ultrasonic parameters were obtained by routine TTE, and the strain index and different parameters of the left ventricular MW were obtained by dynamic image offline analysis. (3) Results: This study found that (1) compared with the CON group, the CKDN-LVH group had a significantly increased global waste work (GWW) and significantly decreased global work efficiency (GWE), the GWW further increased, and GWE further decreased in the CKDLVH group. There was no significant change in the global work index (GWI) and global constructive work index (GCW) in the CKDN-LVH group, but the GWI and GCW in the CKDLVH group were significantly increased. (2) According to the grouping analysis of systolic blood pressure (SBP), we found that the GWW increased and GWE decreased in CKD patients with an elevated SBP. (3) Correlation analysis showed that the increase of the peak strain dispersion, SBP, and left ventricular mass index and the decrease of the estimated glomerular filtration rate were significantly correlated with the decrease of the GWE and the increase of the GWW. (4) Receiver operating characteristic curve analysis showed that the area under the curve (AUC) of myocardial damage induced by the GWE and GWW in the CKD group and CON group was higher than that of left ventricular global longitudinal strain (AUCs: 0.87 and 0.878 versus 0.72, respectively). (4) Conclusions: Noninvasive left ventricular PSL analysis can be used to evaluate the global MW in patients with CKD. The study justified the role of GWW in the noninvasive assessment of myocardial function in patients with CKD.

Assessment of myocardial injury in neonates born to pregnant women with pregnancy complicated by severe preeclampsia by myocardial work indices: a prospective study.

To evaluate myocardial injury in neonates born to pregnant women with pregnancy complicated by severe preeclampsia by myocardial work indices. A prospective cohort study was performed on 25 preterm infants born to the pregnant women with severe preeclampsia from June 2020 to April 2021 (severe preeclampsia group), and 25 preterm infants born to the pregnant women without severe complications in pregnancy were enrolled as the control group. Echocardiography was performed within 24 hours and at 48-72 hours and 14-28 days after birth to measure conventional parameters. Two-dimensional speckle-tracking echocardiography was performed to construct a noninvasive left ventricular pressure-strain loop based on two-dimensional myocardial strain and left ventricular systolic pressure noninvasively measured, so as to calculate myocardial work indices. Compared with the control group, the severe preeclampsia group had significant reductions in left ventricular global work index and global constructive work within 24 hours after birth (P<0.05), a significant reduction in left ventricular global work efficiency and a significant increase in global waste work at 48-72 hours after birth (P<0.05), and a significant reduction in left ventricular global work efficiency at 14-28 days after birth (P<0.05). Subclinical myocardial injury persists in the neonatal period in preterm infants born to pregnant women with severe preeclampsia.

Myocardial work and left ventricular mechanical adaptations following isometric exercise training in hypertensive patients.

Hypertension is a major risk factor for cardiovascular disease. Isometric exercise training (IET) reduces resting and ambulatory blood pressure; however, few studies have investigated the myocardial adaptations following IET. We randomly assigned 24 unmedicated hypertensive patients in a cross-over study design to 4-weeks of IET and control period, separated by a 3-week washout period. Speckle tracking echocardiography was used to measure left ventricular (LV) mechanics, and global myocardial work indices were derived from non-invasive LV pressure-strain loops constructed from global longitudinal strain (GLS) indexed to brachial systolic blood pressure. IET significantly improved GLS (- 2.3 ± 2%, p < 0.001) and global work efficiency (2.8 ± 2%, p < 0.001), and significantly reduced global wasted work (- 42.5 ± 30mmHg%, p < 0.001) with no significant change during the control period. This is the first evidence to demonstrate that IET significantly improved cardiac health in a relevant patient population. Our findings have important clinical implications for patients with high blood pressure and support the role of IET as a safe and viable therapeutic and preventative intervention in the treatment of hypertension.

Quantitative Analysis of Myocardial Work by Non-invasive Left Ventricular Pressure-Strain Loop in Patients With Type 2 Diabetes Mellitus.

Background: Type 2 diabetes mellitus (T2DM) is a common risk factor for cardiovascular diseases. The aims of this study were to evaluate the changes in the left ventricular myocardial work in T2DM patients using the left ventricular pressure-strain loop (PSL) technique, and to explore the risk factors for the left ventricular myocardial work impairment.Methods: Fifty patients with T2DM and 50 normal controls (NCs) were included in the study. In addition to conventional echocardiography and two-dimensional speckle tracking echocardiography, the left ventricular myocardial work parameters were measured using PSL technology.Results: The absolute value for global longitudinal strain (GLS), global work index (GWI) and, global constructive work (GCW) were significantly decreased in the T2DM group (P < 0.05), while the left ventricular ejection fraction (LVEF) was not significantly different between the T2DM and NC groups. Multivariable linear regression analysis showed that hemoglobin A1c (HbA1c) was independently related to GWI (β = −0.452, P < 0.05), while HbA1c and the diabetes duration were independently related to GCW (β = −0.393, P < 0.05 and β = −0.298, P < 0.05, respectively).Conclusions: Changes in the left ventricular myocardial systolic function in T2DM patients were identified using PSL technology. HbA1c was shown to be an independent risk factor affecting GWI, while HbA1c and diabetes duration were demonstrated to be independent risk factors affecting GCW.

Non-invasive Global and Regional Myocardial Work Predicts High-Risk Stable Coronary Artery Disease Patients With Normal Segmental Wall Motion and Left Ventricular Function.

Background: Previous studies suggested that myocardial work (MW) may identify abnormalities in the left ventricular (LV) function and establish a more sensitive index for LV dysfunction at the early stage. This study aimed to explore the value of global and regional MW parameters in predicting high-risk stable coronary artery disease (SCAD) patients with normal wall motion and preserved LV function.Patients and Methods: A total of 131 patients, who were clinically diagnosed as SCAD with normal wall motion and LV function, were finally included in this study. Global MW parameters, including global work index (GWI), global constructive work (GCW), global waste work (GWW), and global work efficiency (GWE) were measured with non-invasive LV pressure-strain loops constructed from speckle-tracking echocardiography. Regional myocardial work index (RWI) and work efficiency (RWE) were also calculated according to the perfusion territory of each major coronary artery. All patients underwent coronary angiography and were divided into the high-risk SCAD group, the non-high-risk SCAD group, and the No SCAD group according to the range and degrees of coronary arteries stenosis.Results: The global longitudinal strain (GLS), GWI and GCW were statistically different (P < 0.001) among the three groups. In the high-risk SCAD group, GLS, GWI, and GCW were significantly lower than the other two groups (P < 0.05). Receiver operating characteristic analysis demonstrated GWI and GCW could predict high-risk SCAD at a cutoff value of 1,808 mm Hg% (sensitivity, 52.6%; specificity, 87.8%; predictive positive value, 76.3%; predictive negative value, 69.9%) and 2,308 mm Hg% (sensitivity, 80.7%; specificity, 64.9%; predictive positive value, 63.3%; predictive negative value, 80.0%), respectively. Multivariate analyses showed that carotid plaque, decreased GWI, and GCW was independently related to high-risk SCAD. The cutoff values of RWILAD, RWILCX, and RWIRCA were 2,156, 1,929, and 1,983 mm Hg% in predicting high-risk SCAD, respectively (P < 0.001). When we combined RWI in two or three perfusion regions, the diagnostic performance of SCAD was improved (P < 0.001).Conclusions: Both global and regional MW parameters have great potential in non-invasively predicting high-risk SCAD patients with normal wall motion and preserved LV function, contributing to the early identification of high-risk patients who may benefit from revascularization therapy.

A non-invasive left ventricular pressure-strain loop study on myocardial work in primary aldosteronism

We investigated the myocardial work derived from left ventricular pressure-strain loop in patients with primary aldosteronism or primary hypertension. We enrolled 50 patients with primary aldosteronism, 50 age- and sex-matched patients with primary hypertension, and 25 normotensive control subjects. We performed transthoracic echocardiography and speckle-tracking echocardiography-based left ventricular pressure-strain loop analysis to evaluate cardiac structure and function. Patients with primary aldosteronism and those with primary hypertension had similar clinic and ambulatory blood pressures, except that the former had a significantly (P = 0.03) higher nighttime systolic blood pressure. All subjects had normal left ventricular ejection fraction (66.4 ± 4.7%). Patients with primary aldosteronism had a greater left ventricular mass index than those with primary hypertension and the normal controls (111.0 ± 21.6 g/m2 versus 95.7 ± 17.7 and 77.9 ± 13.5 g/m2, respectively, P < 0.001). The global myocardial work index (GWI, 2336 ± 333, 2366 ± 288, and 2292 ± 249 mmHg%, respectively), and global constructive work (GCW, 2494 ± 325, 2524 ± 301, and 2391 ± 193 mmHg%, respectively), were comparable in the three groups (P ≥ 0.18). However, the global work efficiency (GWE) differed significantly (P < 0.001), being lowest in primary aldosteronism (91.1 ± 2.7%), intermediate in primary hypertension (93.5 ± 2.5%) and highest in controls (95.3 ± 1.5%). The opposite was true for the global wasted work (GWW) (205.6 ± 74.6, 142.0 ± 56.4 and 99.4 ± 33.7 mmHg%, respectively, P < 0.001). GWE was significantly correlated with the logarithmically transformed plasma concentration and the urinary excretion of aldosterone in patients with primary aldosteronism or primary hypertension (r = -0.43 for both, P < 0.001). The associations remained statistically significant (P ≤ 0.04) after further adjustment for several factors, including left ventricular mass index and clinic or nighttime blood pressure. In conclusion, GWE decreased and GWW increased in primary hypertension and further in primary aldosteronism, probably because of the adrenal aldosterone hypersecretion and the left ventricular mass index increase, while GWI and GCW were similar, indicating that similar and normalized total myocardial work might be a compensation in hypertension at the expense of work efficiency.

Resting global myocardial work can improve interpretation of exercise stress echocardiography

Sensitivity and specificity of ESE to determine hemodynamically significant coronary artery disease (CAD) is limited by subjective qualitative interpretation resulting in false-positive results. The objective of this study was to determine whether resting myocardial work estimated from non-invasive left ventricular pressure-strain loops can help improve the interpretation of exercise stress echocardiography (ESE). Resting global myocardial work was performed on 288 patients referred for clinically indicated ESE with no resting regional wall motion abnormalities and normal ejection fraction (≥ 55%). Coronary angiography was used to validate the presence of significant CAD in those with a positive ESE. Resting global myocardial work index (GWI) was significantly reduced (p < 0.001) in patients with true-positive (1544 ± 354mmHg%) compared to negative (1819 ± 317mmHg%) and false-positive (1857 ± 344mmHg%) ESE. A GWI of ≤ 1391mmHg (AUC 0.73; sensitivity 94%; specificity 73%) predicted true-positive ESE. Predictors of a true-positive ESE were (1) lower myocardial work efficiency (odds ratio 0.731, 95% CI 0.58-0.92, p = 0.007), (2) lower GWI (odds ratio 0.997, 95% CI 0.996-0.999, p = 0.006) (3) male gender (odds ratio 5.47, 95% CI 1.84-16.31, p = 0.002) and (4) E/e' ratio (odds ratio 1.15, CI 1.01-1.31, p = 0.032). Myocardial work is a potentially valuable quantitative parameter that provides incremental value over qualitative ESE interpretation and improves appropriate patient selection for coronary angiography.

Value of territorial work efficiency estimation in non-ST-segment-elevation acute coronary syndrome: a study with non-invasive left ventricular pressure-strain loops.

Non-ST-segment-elevation acute coronary syndrome (NSTE-ACS) patients with normal left ventricular (LV) ejection fraction (LVEF) and wall motion require a non-invasive tool to detect LV risk areas. This study utilized non-invasive LV pressure-strain loops to evaluate territorial myocardial work efficiency (WE) for identifying obstructive coronary artery stenosis, in patients with non-obstructive or obstructive coronary artery stenosis NSTE-ACS, the latter with or without occlusion. Global and territorial longitudinal strain (LS) analyses were performed via speckle-tracking imaging before coronary angiography. LV pressure-strain loops estimated global and territorial myocardial work index (MWI), constructive work (CW), wasted work (WW), and WE. Receiver operating characteristic curve analysis was used to determine the optimal cutoff value of independent parameters to detect obstructive coronary artery stenosis. Compared with non-obstructive, obstructive coronary artery stenosis showed significantly lower global and territorial LS, MWI, CW, and WE, and higher WW. Territorial LS, MWI, CW, and WE were significantly worse in territories of coronary occlusion. Territorial WE was the best parameter for predicting obstructive coronary artery stenosis (AUC 0.80, cutoff < 96%, sensitivity 73%, specificity 70%, P < 0.001). In patients with NSTE-ACS with normal wall motion and LVEF, territorial WE is more accurate than territorial LS or MWI to identify LV risk areas.

Non-invasive assessment of left ventricular myocardial work in healthy subjects with echocardiography

Purpose: to evaluate the left ventricular (LV) echocardiographic indices of myocardial work using the LV pressure-strain loops method in healthy individuals.Material and methods. The study included 50 healthy subjects (28 men, mean age: 44 ± 14 years). The inclusion criteria were the absence of any cardiovascular diseases and diabetes mellitus. After calculating global longitudinal strain (GLS) from speckle-tracking Echo and inserting values of brachial artery cuff blood pressure (BP), the vendor-specific module constructed non-invasive LV pressure-strain loops. The following parameters were calculated: global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE).Results. The lowest values of GWI in men and women were 1382 mmHg% and 1821 mmHg%, the highest values were 2875 mmHg% and 2589 mmHg%, mean values were 2056 ± 326 mmHg% and 2109 ± 200 mmHg%, respectively. Mean values of GCW were 2292 ± 329 mmHg% in men and 2304 ± 211 mmHg% in women. The median and the highest value of GWW were 66 mmHg% and 313 mmHg% in men and 79,5 mmHg% and 172 mmHg% in women, respectively. The lowest value of GWE were 89% in men and 91% in women. GWI was significantly and naturally correlated only with systolic BP (r = 0,30, р = 0,03) and GLS (r = -0,72, р &lt; 0,001). GCW was significantly correlated with systolic BP (r = 0,36, р = 0,01) and GLS (r = -0,72, р &lt; 0,001) too, however, the negative relationship with the age of the patients was found (r = -0,27, р = 0,04). LV myocardial work indices did not significantly differ between men and women. Coefficients of variation for GWI, GCW and GWE did not exceed 10%, which is typical for good reproducible indices.Conclusion. The study presents values of the echocardiographic LV myocardial work indices, obtained with help of the LV pressure-strain loops method in healthy individuals. The natural correlation of LV myocardial work indices with strain and blood pressure was demonstrated, as well as a dependence on the age of the subjects and good reproducibility.

P1510 Assessment of left ventricular relaxation time constant by noninvasive left ventricular pressure-strain loop: invasive validation

Abstract Introduction Left ventricular (LV) relaxation time constant, Tau (τ), is one of the best indexes to evaluate left ventricular diastolic function and is usually assessed invasively. Tau is the time constant of the exponential regression Pt =(P0-P∞)e-t/τ+P∞ that expresses left ventricular isovolumic pressure decay, where Pt is LV pressure (LVP) at time t, P0 is LVP at dP/dtmin and P∞ is the asymptotic pressure, to which relaxation would lead if completed without LV filling. Several noninvasive methods were developed to calculate Tau, however, they are time-consuming and complicated. Recently, a simple method regional left ventricular pressure–strain loops and myocardial work was introduced and validated. We hypothesize that left ventricular relaxation time constant can be derived and calculated from the LV pressure–strain loops. Objective To calculate noninvasively Tau using LV pressure–strain loops and compare it to invasive Tau assessment. Methods The study includes patients with preserved LV systolic function without significant valvular disease that were scheduled to elective coronary catheterization. During catheterization, a fluid-filled catheter was placed in the LV to measure pressure. Echocardiography was performed simultaneously with LV pressure recording. Three standard apical views were acquired and subsequently 2D strain analysis was performed using commercially available GE software and LV pressure–strain loops were calculated. Doppler signal was used for timing of valvular events. Tau was calculated by the equation τ =P/(-dP/dt) that is a derivative of the ventricular pressure decline P = P0e-t/τ+PB with respect to time. The pressure between peak negative dP/dt and the lowest LV pressure shortly after mitral valve opening was used for this calculation. The study was approved by the institutional ethics committee. Results Forty patients, (mean age 65.1 ± 10.9 years, 27 male, BSA1.93 ± 0.18 m2) were included in the study. Heart rate and the mean blood pressure at the time of catheterization were 69.9 ± 11.8 min-1 and 85.2 ± 18.8 mmHg, respectively. The mean LV end diastolic diameter was 44 ± 4 mm, the LV mass was 86.7 ± 25.2 g/m2, LVEF 58.4 ± 6.6% and GLS 21.0 ± 3.2%. Tau, calculated noninvasively using derivative method was significantly lower than invasively derived measurement (40.1 ± 13.4 vs 49.8 ± 7.7 msec, p = 0.002). However, a significant positive correlation was observed between the two methods (r =0.67, p &amp;lt;0.001, Figure). Conclusions This preliminary study demonstrates that Tau estimated by a noninvasive method using LV pressure–strain loops has a good correlation with Tau measured invasively. Therefore, Tau can be estimated noninvasively using novel left ventricular pressure–strain loop method. Abstract P1510 Figure.

Global Myocardial Work Is Superior to Global Longitudinal Strain to Predict Significant Coronary Artery Disease in Patients With Normal Left Ventricular Function and Wall Motion

Noninvasive detection of functionally significant coronary artery disease (CAD) by echocardiography remains challenging, with the need to perform stress imaging to detect ischemia. The aim of this study was to determine whether global myocardial work (MW), derived from noninvasive left ventricular (LV) pressure-strain loops at rest, can predict significant CAD in patients without regional wall motion abnormalities and preserved LV ejection fraction (EF). One hundred and fifteen patients referred for coronary angiography who had EF≥55%, no resting regional wall motion abnormalities, and no chest pain were assessed using echocardiography. Global MW was derived from noninvasive LV pressure-strain loops constructed from speckle-tracking echocardiography indexed to brachial systolic blood pressure. Global constructive work represented the sum of positive work due to myocardial shortening during systole and negative work due to lengthening during isovolumic relaxation. Global wasted work represented energy loss by myocardial lengthening in systole and shortening in isovolumic relaxation. Global MW efficiency was derived from the percentage ratio of constructive work to the sum of constructive work and wasted work. Patients with significant CAD demonstrated a significantly reduced global MW (P<.001) compared with those without CAD. Global longitudinal strain was significantly reduced (P<.001) in patients with multivessel CAD but not those with single-vessel CAD (P=.47). Receiver operating characteristic curve analysis demonstrated that global MW was the most powerful predictor of significant CAD (area under the curve=0.786) and was superior to global longitudinal strain (area under the curve=0.693). The optimal cutoff global MW value to predict significant CAD was 1,810mm Hg% (sensitivity, 92%; specificity, 51%). Noninvasive global MW derived using LV pressure-strain loops at rest is a more sensitive index than global longitudinal strain to detect significant CAD in patients with no regional wall motion abnormalities and normal EF. This is a potential valuable clinical tool to assist in the early diagnosis of CAD.

4922Novel non-invasive left ventricular pressure-strain loop imaging demonstrates reduced myocardial work in cardiomyopathy with significant regional variation in non-ischemic cases

Background: Non-invasive left ventricular (LV) pressure-strain loop imaging is a novel method of calculating myocardial work (MW). The total area within the pressure-strain loop represents global MW (Figure1A). Myocardial shortening during systole and lengthening during isovolumic relaxation is classified as constructive work (CW) while myocardial lengthening during systole and shortening during isovolumic relaxation is classified as wasted work (WW). Purpose: Non-ischemic (CMPN-ISC) and ischemic cardiomyopathy (CMPISC) heart disease etiology influences management, prognosis as well as electromechanical correlates in heart failure. Differences in global MW and regional MW in patients with CMPN-ISC and CMPISC were assessed. Methods: Strain analysis was performed in 34 patients divided into: 1) Controls (n=10); 2) CMPN-ISC (n=10) (EF<40%; no evidence of significant coronary artery disease); 3) CMPISC (n=14) (EF<40%; coronary artery stenosis) immediately prior to coronary angiography. Dedicated MW software normalized standard LV pressure curves to brachial systolic cuff pressure and isovolumic and ejection duration. MW efficiency (GWE) was derived from the percentage ratio of: CW/(CW+WW). Segmental wasted work between septal and lateral segments were compared between CMPN-ISC and CMPISC. Results: Significantly higher global MW and GWE (p<0.05) was observed in controls. CMPISC demonstrated the lowest global MW (780mmHg%) but was not significantly different to CMPN-ISC (1054mmHg%). CMPN-ISC WW was significantly higher (p<0.05) compared to CMPISC (259 vs 185 mmHg%). Regional septal WW was significantly higher (p<0.05) in CMPN-ISC (459mmHg%) vs lateral WW (174mmHg%) (Figure1C). There was no significant difference between septal (198mmHg%) and lateral (161mmHg%) WW in CMPISC.