Global myocardial work in coronary artery disease patients without regional wall motion abnormality: Correlation with Gensini-score.

BACKGROUND: Early detection of coronary atherosclerotic diseases (CAD) without regional wall motion abnormality (RWMA) is important for improving the outcome of cardiovascular events. Global myocardial work (GMW), including global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global myocardial work efficiency (GWE), offer comprehensive quantitative assessment of myocardial function in CAD. HYPOTHESIS: We hypothesized that GMW could provide incremental value in detecting CAD without RWMA. METHODS: One hundred and twenty-four patients referred for coronary angiography (CAG) without resting RWMA were enrolled in this study. Global longitudinal strain (GLS), GWI, GCW, GWW, GWE were quantified. The severity of coronary lesions was evaluated by Gensini score (GS) based on CAG. We further divided CAG-confirmed CAD patients into three subgroups according to the tertiles of GS: low 0 < GS ≤ 17, mid 17 < GS ≤ 38, and high GS > 38. RESULTS: Compared with control, CAD patients showed decreased GLS, GWE, GWI, GCW but an increased GWW. Compared to low-GS group, GWW was increased in the mid-GS group. GLS, GWE, GWI and GCW were decreased in the high-GS group while GWW was increased. Receiver operator characteristic curve analysis demonstrated that GWE was the most powerful predictor of high-GS and was superior to GLS. GWE under 92.0% had the optimal sensitivity and specificity for identifying high-GS. CONCLUSION: The proposed GWE, which outperformed the conventional GLS, could be considered as a potential predictive indicator to help to detect severe coronary disease in non-RWMA CAD patients.

Left Ventricular Pressure Strain Loops for Evaluation of Myocardial Work in Type 2 Diabetic Patients with Hypertension.

BACKGROUND: Type 2 diabetes mellitus (T2DM) and hypertension (HT) are the two most common underlying diseases worldwide, and they often coexist. The long-term existence of both may lead to left ventricular dysfunction. Therefore, evaluating the cardiac function of T2DM patients with HT is vital to guide treatment and improve prognosis. Left ventricular pressure strain loops (LVPSL) combine left ventricular strain and afterload, which can quantify left ventricular energy expenditure and detect left ventricular subclinical systolic dysfunction. Many studies have focused on myocardial work (MW) in uncomplicated T2DM patients or simple HT patients, but a few have focused on T2DM patients with HT. OBJECTIVE: The study aimed to evaluate the MW changes in T2DM patients with HT using LVPSL and to find independent related factors of MW parameters. METHODS: 40 T2DM patients, 35 HT patients, 40 T2DM patients with HT (T2DM+HT group), and 35 controls were enrolled. The differences between clinical data, conventional ultrasound parameters, and MW parameters were analyzed among the four groups. RESULTS: The global longitudinal strain (GLS) of the T2DM group, HT group, and T2DM+HT group was lower than the control group (P<0.05). The global work index (GWI) and global constructive work (GCW) in the T2DM group were lower than other groups (P<0.05). The GWI of the HT group was higher than other groups (P<0.05), while GCW was only higher than the T2DM group and T2DM+HT group (P<0.05). The GWI and GCW of the T2DM+HT group were higher than the T2DM group and were lower than the HT group(P<0.05), while there was no significant difference with the control group. HT group and T2DM+HT group had higher global work waste (GWW) (P<0.05). The global work efficiency (GWE) of the T2DM+HT group was lower than other groups (P<0.05). Systolic blood pressure (SBP) and glycosylated hemoglobin (HbA1c) were independent factors of each MW parameter. CONCLUSION: LVPSL can recognize left ventricular subclinical systolic dysfunction early in patients with T2DM and HT. Compared to simple T2DM or HT, the combination of T2DM and HT had greater damage to left ventricular systolic function. SBP and HbA1c are two factors that have a considerable impact on MW parameters. The impact of afterload on MW parameters should be paid more attention to.

State-of-the-Art: Noninvasive Assessment of Left Ventricular Function Through Myocardial Work.

The assessment of myocardial work (MW) using noninvasive pressure-strain loop analysis is a novel echocardiographic method that provides a more precise assessment of cardiac performance by considering the left ventricular loading condition. By integrating various MW components such as index, efficiency, and constructive and wasted work, an extensive analysis of left ventricular mechanics and energetics can be achieved. This approach offers a more comprehensive assessment of global cardiac function and performance, surpassing conventional surrogate indices. In this review, we aim to summarize the existing knowledge on MW and its distinctive characteristics in various cardiac pathologies.

Serial Non-Invasive Myocardial Work Measurements for Patient Risk Stratification and Early Detection of Cancer Therapeutics-Related Cardiac Dysfunction in Breast Cancer Patients: A Single-Centre Observational Study.

Serial transthoracic echocardiographic (TTE) assessment of LVEF and GLS are the gold standard in screening Cancer Therapeutics-Related Cardiac Dysfunction (CTRCD). Non-invasive left-ventricle (LV) pressure-strain loop (PSL) emerged as a novel method to quantify Myocardial Work (MW). This study aims to describe the temporal changes and longitudinal trajectories of MW indices during cardiotoxic treatment. We included 50 breast cancer patients with normal LV function referred for anthracycline therapy w/wo Trastuzumab. Medical therapy, clinical and echocardiographic data were recorded before and 3, 6, and 12 months after initiation of the chemotherapy. MW indices were calculated through PSL analysis. According to ESC guidelines, mild and moderated CTRCD was detected in 10 and 9 patients, respectively (20% CTRCDmild, 18% CTRCDmod), while 31 patients remained free of CTRCD (62% CTRCDneg). Prior to chemotherapy MWI, MWE and CW were significantly lower in CTRCDmod than in CTRCDneg and CTRCDmild. Overt cardiac dysfunction in CTRCDmod at 6 months was accompanied by significant worse values in MWI, MWE and WW compared to CTRCDneg and CTRCDmild. MW features such as low baseline CW, especially when associated with a rise in WW at follow-up, may identify patients at risk for CTRCD. Additional studies are needed to explore the role of MW in CRTCD.

Left bundle branch pacing on mechanical synchrony and myocardial work in bradycardia patients.

Left bundle branch pacing (LBBP) has emerged as a novel physiological pacing method to produce narrower QRS duration, but whether it could restore mechanical synchrony and improve myocardial work still lacks sufficient evidence. Therefore, the goal of this study was to evaluate mechanical synchrony and myocardial work in LBBP. We collected 20 patients with LBBP due to symptomatic bradycardia and another 29 age-matched patients with right ventricular pacing (RVP). For LBBP patients, cardiac electro-mechanical synchrony and myocardial work were measured at baseline and 7 days after implantation and compared with the RVP patients. In the LBBP group, paced QRS duration and mechanical synchrony were not significantly different from baseline(all P > 0.05), but significantly smaller than that in the RVP group (all P<0.05). Meanwhile, global longitudinal strain (GLS) in LBBP was greater than that in the RVP group (17.7 ± 3.5% vs. 14.8 ± 3.1%, P < 0.05). Global myocardial work index and global constructive work were also better than that in the RVP group(all P<0.05). Global work efficiency was 91.9 ± 3.1%, which was greater when compared with RVP (P < 0.05). LBBP provides better cardiac electro-mechanical synchrony and more effective myocardial work than that in RVP, thus improving global heart function.

Subclinical left ventricular myocardial dysfunction in patients with obstructive sleep apnea syndrome: insights from noninvasive left ventricular myocardial work analysis.

BACKGROUND: Obstructive sleep apnea syndrome (OSAS) is associated with various cardiovascular diseases and has aroused public concern. Early detection for declining myocardial function is of great significance. This study was aimed at noninvasively evaluating the subclinical left ventricular (LV) myocardial dysfunction with LV pressure-strain loop (PSL) in patients with OSAS having normal LV ejection fraction. METHODS: We enrolled 200 patients with OSAS who visited the Beijing Chaoyang Hospital between February 2021 and December 2021. According to the apnea-hypopnea index (AHI), patients were divided into mild, moderate, and severe groups. The global longitudinal strain (GLS) of the left ventricle was analyzed by two-dimensional speckle tracking echocardiography. The LV PSL was used to assess global work index (GWI), global constructive work (GCW), global waste work (GWW), and global work efficiency (GWE), and comparisons were made among groups. RESULTS: GLS was significantly lower in the severe group than in mild and moderate group. GWI, GCW, and GWE were lower in the severe group than in mild and moderate groups. GWW was significantly higher in the severe group than in the mild group. GLS, GWI, and GWE were moderately correlated with AHI (Spearman's ρ = -0.468, -0.321, and -0.319, respectively; P < 0.001), whereas GCW and GWW showed a weak correlation with AHI (Spearman's ρ = -0.226 and 0.255 respectively; P < 0.001). Multiple regression analyses revealed AHI was independently associated with GWI after adjusting for SBP, GLS, e', etc. AHI was independently associated with GCW after adjusting for SBP, GLS, etc. CONCLUSIONS: The LV PSL is a new technique to noninvasively detect myocardial function deterioration in patients with OSAS and preserved LV ejection fraction. Increased severity of OSAS was independent associated with both decreased GWI and GCW.

Evaluation of myocardial work in patients with hypertrophic cardiomyopathy and hypertensive left ventricular hypertrophy based on non-invasive pressure-strain loops.

Background: The capacity to distinguish hypertrophic cardiomyopathy (HCM) from hypertensive left ventricular hypertrophy (H-LVH) based on morphological features obtained by conventional echocardiography is limited. We investigated the global myocardial work of the left ventricle in two types of hypertrophies using the non-invasive myocardial work index (NMWI). Methods: Conventional echocardiography was performed on 107 subjects with preserved left ventricular ejection fraction (LVEF ≥ 50%), who comprised patients with HCM (n = 40), H-LVH (n = 35), and healthy people with normal blood pressure and left ventricular structure (n = 32). Except for the conventional echocardiographic parameters, the left ventricular myocardial work parameters based on pressure-strain loops, including global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), were evaluated in three groups. Multivariate discriminant analysis and receiver operating characteristic (ROC) curve were used to evaluate the incremental value of NMWI for distinguishing HCM from H-LVH. Results: Compared to the control group, GWI and GCW were significantly lower in HCM patients (P < 0.05), whereas GWI was significantly higher in H-LVH patients. GWW was higher and GWE was significantly decreased in both HCM and H-LVH patients than in the control group (P < 0.05). Multivariate discriminant analysis and ROC curve revealed that the inter-ventricular septum thickness (IVST)/left ventricular posterior wall thickness (LVPWT) and GCW were each able to distinguish HCM from H-LVH. The combination of IVST/LVPWT and GCW discriminated HCM and H-LVH with a higher predictive accuracy of 94.7%. Conclusion: NMWI may provide additional information in evaluating the myocardial function in patients with HCM and H-LVH. Myocardial work combined with conventional echocardiography could improve the clinical diagnostic accuracy of distinguishing HCM and H-LVH.

Predictive value of the echocardiographic noninvasive myocardial work index for left ventricular reverse remodeling in patients with multivessel coronary artery disease after percutaneous coronary intervention.

Background: Coronary artery disease (CAD) can lead to left ventricular (LV) remodeling, which, in adverse cases, has been associated with heart failure and increased mortality. Here, we aimed to evaluate the predictive value of the noninvasive myocardial work index (NIMWI) for LV reverse remodeling in patients with multivessel CAD after percutaneous coronary intervention (PCI). Methods: A total of 88 consecutive patients with multivessel CAD treated with PCI were identified and categorized according to the presence of LV reverse remodeling 3 months after PCI [≥15% decrease in the LV end diastolic volume (LVEDV)]. With the LV pressure-strain loop (PSL) technique, NIMWIs, including the global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), were statistically compared between the reverse LV remodeling group and nonreverse LV remodeling group 1 week before PCI. Results: Significantly lower GWI, GCW, and GWE, and significantly higher GWW were observed in the reverse LV remodeling group compared with the nonreverse LV remodeling group (P<0.05). Left ventricular mass index (LVMI), GCW, and GWE were independently associated with early LV reverse remodeling. Receiver operating characteristic (ROC) curve analysis demonstrated that GCW was the most powerful predictor of early LV reverse remodeling in patients with CAD [area under the curve (AUC) =0.867]. The optimal cutoff GCW value predictive of early LV reverse remodeling was 1,438.5 mmHg% (sensitivity, 85%; specificity, 70%). Conclusions: GCW, among the NIMWIs, may be the major predictor of LV reverse remodeling in patients with multivessel CAD after PCI. NIMWI could potentially provide a new reference index for the quantitative evaluation of LV myocardial work.

Pressure-Strain Loops, a Novel Non-invasive Approach for Assessment of Children with Cardiomyopathy.

Non-invasive myocardial work (MW) by left ventricular (LV) pressure-strain loops (PSL) is a novel method for assessing myocardial function while adjusting for afterload, yet pediatric data remain lacking. The aims of this study were to investigate the different patterns of LV PSL and non-invasive MW in pediatric patients with hypertrophic (HCM) and dilated cardiomyopathy (DCM) and their association with exercise tolerance. We included 110 pediatric subjects (mean age, 13 ± 4 years, 35 DCM, 40 HCM, and 35 healthy controls). Standard and speckle-tracking echocardiography were performed. LV PSLs were generated, and global work index (GWI), MW efficiency (GWE), constructive work (GCW), and wasted work (GWW) were compared between groups. Regression analysis was used to assess the influence of ventricular function, dimensions, wall thickness, and wall stress on MW and to predict the association between MW and VO2 max as a surrogate of exercise capacity. Patients with DCM had significantly lower GWI compared to controls (GWI 479.6 ± 263.0 vs 1610.1 ± 211.0, P < 0.005). GWE was significantly reduced in DCM (79.3 ± 7.9 vs 95.2 ± 1.3, P < 0.005) due to significantly reduced GCW and increased GWW. HCM patients had significant reduction in GWI and GWE from normal (1237.7 ± 449.1 vs 1610.1 ± 211.0, P = 0.001 and 89.6 ± 4.9 vs 95.2 ± 1.3, P < 0.005, respectively), although less severe than with DCM. In a multivariate regression analysis, GWE had the highest association with VO2 max in both cohorts (DCM: ß = 0.68, P = 0.001, HCM: ß = 0.71, P = 0.007). Non-invasively assessed myocardial work and LV PSLs provide novel insights into the mechanisms of dysfunction in pediatric patients with cardiomyopathy with good prediction of clinical status and thus hold promise to further explore myocardial mechanistic with clinical relevance in different disease entities.

Left ventricular systolic function in children with repaired tetralogy of Fallot by pressure-strain loops / 中华超声影像学杂志

Objective:To quantify the left ventricular myocardial work in patients with repaired tetralogy of Fallot (TOF), and to evaluate the changes in left ventricular systolic function after TOF repair by pressure-strain loops (PSL).Methods:Seventy-six cases of children after TOF complete surgery in Shenzhen Children′s Hospital from September 2015 to September 2021 were analyzed retrospectively. There were 41 cases in the ≤4-year group and 35 cases in the >4-year group. Seventy-six healthy children with matched body surface area in the same period were selected as the control group. All subjects underwent complete echocardiography and quantitative analysis of left ventricular myocardial work, including global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE). Compared with the normal control group, the changes of left ventricular myocardial work after TOF repair were analyzed. For patients with complete echocardiographic data before and after surgery, the correlation between postoperative left ventricular myocardial work and preoperative degree of right ventricular outflow tract (RVOT) obstruction was analyzed.Results:①In the ≤4-year group, compared with control subjects, GLS, GWI, GCW, GWE decreased, and GWW increased in patients with repaired TOF. All the differences were statistically significant [(-20.00±1.52)% vs (-21.59±1.73)%, (1 349.37±133.63)mmHg% vs (1 553.51±246.09)mmHg%, (1 589.39±167.85)mmHg% vs (1 749.12±249.45)mmHg%, 94.0%(94.0%, 95.0%) vs 96.0%(95.0%, 97.0%), (78.80±20.53)mmHg% vs (62.27±21.44)mmHg%; all P<0.05]. ②In >4-year group, compared with the control group, GLS, GWI, GWE decreased, and GWW increased in patients with repaired TOF. All the differences were statistically significant [(-19.89±1.66)% vs (-21.31±1.60)%, (1 486.09±172.42)mmHg% vs (1 713.14±227.05)mmHg%, 96.0%(94.0%, 96.0%) vs 97.0%(96.0%, 97.0%), 75.00(65.00, 95.00)mmHg% vs 55.00(42.00, 71.00)mmHg%; all P<0.05]. ③GWW was negatively correlated with preoperative RVOT diameter and RVOT-Z score( r=-0.422, -0.433; both P<0.05). GWE was positively associated with preoperative RVOT diameter and RVOT-Z score( r=0.441, 0.540; both P<0.05). ④GLS, GWI, GCW, GWW, GWE had good repeatability within and between observers.All the differences were not statistically significant (all P>0.05). Conclusions:Left ventricular systolic function in patients with repaired TOF is lower than that in healthy children of the same age by echocardiography PSL, although traditional indicators are still within the normal range. Patients with more severe RVOT obstruction before surgery have worse left ventricular systolic function after operation. Quantification of left ventricular myocardial work by echocardiography PSL is helpful for long-term follow-up of children after TOF repair.

Pressure-strain loops technique detects the effects of different pacing modes of left bundle branch on left ventricular myocardial work / 中华超声影像学杂志

Objective:To evaluate the effects of different pacing modes (unipolar/bipolar) under left bundle branch pacing(LBBP) on ventricular mechanical synchrony and myocardial work using the pressure-strain loop technique.Methods:Twenty-nine patients with LBBP due to symptomatic bradycardia were collected as LBBP group in Sun Yat-sen Memorial Hospital of Sun Yat-sen University from December 2018 to July 2020. Another 29 matched patients with right ventricular pacing (RVP) during the same period were also included as a RVP group. Each LBBP patient was programmed to different pacing modes (uni-/bio-polar) within 1 week after the operation.Under each pacing mode, the inter- and intra-ventricular mechanical synchronization were evaluated. Meanwhile, the global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) were obtained by the left ventricular pressure-strain loops technique.Results:Compared with the RVP group, the mechanical synchrony in the LBBP group was significantly improved (all P<0.05). GWI, GCW, and GWE increased, while GWW decreased, and the differences were statistically significant (all P<0.05), there were no significant differences in ventricular mechanical synchronization, GWI, GCW, GWE, and GWW between unipolar and bipolar pacing in the LBBP group (all P>0.05), there were no significant differences in these parameters when increasing output voltage (all P>0.05). Conclusions:LBBP induces better mechanical synchronization and higher myocardial work efficiency than RVP. Different LBBP pacing modes do not affect ventricular mechanical synchronization and myocardial work efficiency.

Quantitative study of left ventricular pressure strain loop in evaluating myocardial work in patients with different degrees of coronary artery stenosis / 中国医师杂志

Objective:To evaluate the myocardial work of patients with different degrees of coronary artery stenosis with normal left ventricular ejection fraction and no segmental ventricular wall motion abnormality by left ventricular pressure-strain ring (PSL), and to explore the clinical value of myocardial work parameters in predicting severe coronary artery stenosis.Methods:The data of 238 patients undergoing coronary angiography (CAG) in the Affiliated Hospital of Jining Medical University from December 2020 to August 2021 was prospectively collected. According to the results of CAG, the patients were divided into control group, moderate stenosis group, severe stenosis (1-2 branches) group, severe stenosis (complex multiple branches) group. Global longitudinal strain (GLS), global work index (GWI), global constructive work (GCW), global work waste (GWW) and global work efficiency (GWE) were measured by PSL. Univariate and multivariate logistics regression were used to analyze the influencing factors of severe coronary artery stenosis. The receiver operating characteristic (ROC) curve was constructed to analyze the predictive value of GLS, GWI, GCW, GWW and GWE for severe coronary artery stenosis.Results:The GLS, GWI, GCW and GWE in severe stenosis group were lower than those in control group and moderate stenosis group (all P<0.05), while GWW was higher than those in control group and moderate stenosis group (all P<0.05); the GWI, GCW and GWE in severe stenosis (complex multiple branches) group were lower than those in severe stenosis (1-2 branches) group (all P<0.05), while GWW was higher than those in severe stenosis (1-2 branches) group (all P<0.05). Multivariate logistic regression analysis showed that GWE was an independent influencing factor for severe coronary stenosis ( OR=0.266, P<0.05). Compared with GLS, GWI, GCW and GWW, GWE had the largest area under the curve (0.920) to predict severe coronary stenosis, with sensitivity of 92.24% and specificity of 73.77%. The intra observer and inter observer correlation coefficients of GWI, GCW, GWW and GWE analyzed by two ultrasound physicians were 0.916 and 0.907, 0.989 and 0.981, 0.932 and 0.955, 0.931 and 0.937, respectively, which showed good repeatability. Conclusions:PSL provides a new method for quantitative evaluation of left ventricular systolic function in patients with coronary artery stenosis. GWE can be used as a sensitive indicator to predict patients with severe coronary artery stenosis, and is worth to be popularized and applied in the clinical.

Myocardial Work by Echocardiography: Principles and Applications in Clinical Practice.

Left ventricular (LV) global longitudinal strain (GLS) has established itself in the last decade as a reliable, more objective method for the evaluation of LV systolic function, able to detect subtle abnormalities in LV contraction even in the presence of preserved ejection fraction (EF). However, recent studies have demonstrated that GLS, similar to LV EF, has important load dependency. Non-invasive myocardial work (MW) quantification has emerged in the last years as an alternative tool for myocardial function assessment. This new method, incorporating measurement of strain and LV pressure, has shown to overcome GLS and LV EF limitations and provide a loading-independent evaluation of myocardial performance. The presence of a commercially available echocardiographic software for the non-invasive MW calculation has allowed the application of this new method in different settings. This review sought to provide an overview on the current knowledge of non-invasive MW estimation, showing its potential applications and possible added value in clinical practice.

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.

Assessment of Left Ventricular Global Myocardial Work in Patients With Different Degrees of Coronary Artery Stenosis by Pressure-Strain Loops Analysis.

Global myocardial work (MW) analysis by pressure-strain loops (PSL) allows the non-invasive assessment of left ventricular (LV) function. We aimed to investigate the relationship between LV global MW and the degree of coronary artery stenosis in suspected coronary artery disease (CAD) patients with normal LV ejection fraction and regional wall motion. A total of 164 suspected CAD patients were divided into four groups according to coronary artery angiography. The results showed that global work efficiency (GWE) as the most significant predictor in all MW parameters had the optimal cut-off value of 94.5% for detecting moderate stenosis, and the sensitivity and specificity was 89.7% and 85.8%, respectively. A cut-off value of 94.0% for GWE was the most significant predictor of severe stenosis, and the sensitivity and specificity was 81.4% and 76.1%, respectively. In conclusion, LV global MW is a sensitive tool in detecting the degree of coronary artery stenosis and a potential valuable method to provide early diagnosis for CAD patients.

Ultrasound-based estimation of remaining cardiac function in LVAD-supported ex vivo hearts.

Left ventricular assist devices (LVAD) provide cardiac support to patients with advanced heart failure. Methods that can directly measure remaining LV function following device implantation do not currently exist. Previous studies have shown that a combination of loading (LV pressure) and deformation (strain) measurements enables quantitation of myocardial work. We investigated the use of ultrasound (US) strain imaging and pressure-strain loop analysis in LVAD-supported hearts under different hemodynamic and pump unloading conditions, with the aim of determining LV function with and without LVAD support. Ex vivo porcine hearts (n = 4) were implanted with LVADs and attached to a mock circulatory loop. Measurements were performed at hemodynamically defined "heart conditions" as the hearts deteriorated from baseline. Hemodynamic (including LV pressure) and radio-frequency US data were acquired during a pump-ramp protocol at speeds from 0 (with no pump outflow) to 10 000 revolutions per minute (rpm). Regional circumferential (εcirc ) and radial (εrad ) strains were estimated over each heart cycle. Regional ventricular dyssynchrony was quantitated through time-to-peak strain. Mean change in LV pulse pressure and εcirc between 0 and 10 krpm were -21.8 mm Hg and -7.24% in the first condition; in the final condition -46.8 mm Hg and -19.2%, respectively. εrad was not indicative of changes in pump speed or heart condition. Pressure-strain loops showed a degradation in the LV function and an increased influence of LV unloading: loop area reduced by 90% between 0 krpm in the first heart condition and 10 krpm in the last condition. High pump speeds and degraded condition led to increased dyssynchrony between the septal and lateral LV walls. Functional measurement of the LV while undergoing LVAD support is possible by using US strain imaging and pressure-strain loops. This can provide important information about remaining pump function. Use of novel LV pressure estimation or measurement techniques would be required for any future use in LVAD patients.

Global work index correlates with established prognostic parameters of heart failure.

AIM: Identification of patients with heart failure and a poor prognosis is paramount to ensure timely and adequate treatment. We investigated the relationship between the new measures of noninvasive pressure-strain analysis, such as the global work index (GWI), and established prognostic parameters of echocardiography, cardiopulmonary exercise test (CPX), and N-terminal pro-B-type natriuretic peptide (NT-pro-BNP). METHODS AND RESULTS: We retrospectively analyzed data of 51 patients with heart failure. Echocardiography and CPX were performed, and NT-pro-BNP was determined. Patients with a GWI < 500 mm Hg% had a mean LVEDV of 286.1 ± 100.8 mL, an LVEF of 21.3 ± 5.7%, and a stroke volume (SV) of 45.9 ± 11.6 mL, and patients with a GWI > 1000 mm Hg% had an LVEDV of 147.9 ± 39.6 mL, an LVEF of 42.6 ± 4.8%, and a SV of 70.9 ± 14.3 mL. The GWI also showed a significant correlation with peak oxygen consumption (peak VO2 ) (r = .521; P < .001) and with NT-pro-BNP (r = .635; P < .001). Patients with a GWI of <500 mm Hg% had a significantly higher NT-pro-BNP (median 2415 pg/mL [IQR 1071, 5933]) and a lower peak VO2 (9.5 mL/min/kg ± 2.6) compared to patients with a GWI of >1000 mm Hg% (NT-pro-BNP median 253 pg/mL [IQR 150, 549]; peak VO2 15.6 ± 4.2 mL/min/kg). CONCLUSION: GWI correlates with known prognostic markers of heart failure. A GWI of <500 mm Hg% was a predictor of severely impaired ejection fraction, very low exercise capacity, and strongly elevated NT-pro-BNP, indicating a poor prognosis.

Research progresses of ultrasonic pressure strain loops technique in evaluation of myocardial work / 中国医学影像技术

Based on 2D speckle tracking imaging (2D-STI), myocardium layer-specific strain can be used for quantitative assessment of myocardial function, but is load dependent. Added after-load (blood pressure) measurement to myocardium layer-specific strain, pressure strain loops (PSL) technique can effectively restrict load dependence and quantitatively analyze the work of whole and segmental myocardium. The research progresses of PSL in evaluation of myocardial work were reviewed in this article.