Global Myocardial Work Efficiency Research Articles

Assessment of left ventricular systolic function by non-invasive pressure-strain loop area in young male strength athletes

BackgroundThe health of athletes has been recognized as a worldwide public concern with more reported sudden cardiac deaths (SCD). Therefore, early detection of abnormal heart function in athletes can help reduce the risk of exercise. A novel valid non-invasive method to evaluate left ventricular (LV) myocardial work (MW) using LV pressure-strain loop (PSL), was used in this paper to explore LV systolic function in young male strength athletes.MethodsThirty-six professional young male strength athletes (the athlete group) and 32 healthy, age-matched young men (the control group) were involved in the study. The LVMW parameters were calculated as the area of PSL by two-dimensional speckle tracking echocardiography (2D-STE) and peak systolic LV pressure. The differences between two groups of data and the predictive efficacy of MW parameters for LV systolic function were analyzed.ResultsThe athlete group had significantly higher values of global wasted myocardial work (GWW) and peak strain dispersion (PSD) than did the control group (P<0.05). Global myocardial work index (GWI), global constructive myocardial work (GCW) and global longitudinal strain (GLS) were lower in the athlete group than that in the control group, although statistical significance was not reached (P>0.05). Due to the proportion of GWW and GCW, statistically significant reduction was found in global myocardial work efficiency (GWE) in the athlete group. Conventional echocardiography parameters were well correlated with GWW and GWE (P<0.05). The best predictor of LV myocardial contractile performance in the athletes using receiver operating characteristic curve (ROC) was GWE, with the area under ROC (AUC) of 0.733, sensitivity of 83.3% and specificity of 59.4%.ConclusionsSubclinical changes have appeared in the hearts of young male strength athletes after long-term intensive exercise and LVMW parameters by PSL play an important role in the evaluation of athlete’s LV contractile performance.

Global constructive work and left atrial reservoir function is reduced in patients with heart failure with preserved ejection fraction compared with patients with preclinical diastolic dysfunction

Abstract Heart failure with preserved ejection fraction (HFpEF) remains an unresolved issue with morbidity and mortality comparable with that of reduced EF HF. Diastolic dysfunction (DD) is the hallmark of HFpEF but it is unclear why some patients do not develop symptoms and remain in preclinical DD (PDD) stage with the same degree of DD as patients with HFpEF. We assumed that patients with HFpEF might have more deteriorated global myocardial work (GW) and left atrial reservoir longitudinal strain (LALS) parameters compared with PDD patients. Methods 210 patients (150 female, mean age 71±5 years) of which 118 with PDD and 92 with HFpEF were enrolled in this study. PDD was diagnosed if patients had normal NT-proBNP values, and at least 3 of the following echocardiographic criteria at rest or after diastolic stress echocardiography: end-systolic left atrial volume index (LAVi) &amp;gt;34 ml/m2, LV E/e' &amp;gt;13, average LV e' &amp;gt;8.5, and systolic pulmonary artery pressure &amp;gt;30 mmHg. GW index (GWI) was obtained from pressure-strain loops composed from speckle tracking analysis indexed to brachial systolic blood pressure, global constructive work (GCW) was measured as the sum of positive work due to myocardial shortening during systole and negative work due to lengthening during isovolumic relaxation, global wasted work (GWW) was calculated as energy loss by myocardial lengthening in systole and shortening in isovolumic relaxation, and GW efficiency (GWE) as the percentage ratio of constructive work to the sum of constructive work and wasted work. LALS was measured by speckle tracking echocardiography as average value of two basal segments in apical 4 chamber view along LAVi and 4D LV mass index (LVMi) offline by experienced echocardiographer who was unaware of the study aims. Results Patients with PDD and HFpEF have comparable values of LAVi, LVMi, GWI, GWW, and GWE (LAVi 38.4±3.9 ml/m2 vs 39.1±4.1 ml/m2, p=NS; LVMi 82.8±11.4 g/m2 vs 83.5±10.2 g/m2, p=NS; PDD GWI 2389±154 mmHg% vs 2368±139 mmHg%, p=NS; GWW 62±5 mmHg% vs 65±4 mmHg%, p=NS; GWE PDD 89±9% vs 87±11%, p=NS). LALS and GCW were significantly reduced in patients with HFpEF compared with PDD patients (LALS 21.3±7% vs 29±5%, p&amp;lt;0.01; GCW 1964±112 mmHg% vs 2259±164 mmHg%, p&amp;lt;0.01). Conclusion Patients with HFpEF have reduced LALS and GCW compared with PDD patients. Both parameters are indicative for LA and LV myocardial fibrotic burden respectively which might be one of the probable explanations of PDD transition to HFpEF. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Committee of Science at Ministry of Education of Republic of Armenia

Exercise induced reduction in myocardial work predicts significant coronary artery disease in patients with false negative stress echocardiography

Abstract Stress echocardiography (SE) is a reliable technique for the diagnosis of coronary artery disease (CAD) with high sensitivity and specificity. However in patients with small left ventricular (LV) cavity caused by marked concentric hypertrophy the sensitivity of SE is low. We assumed that in patients with false negative SE evaluation of global myocardial work (GW) might detect significant CAD. Methods 238 patents with chest pain (98 female, mean age 61±5 years) without history of CAD were referred to SE for CAD confirmation. 94 (39.5%) patients had negative SE and were enrolled in our study for re-examination. Age and gender matched 50 healthy subjects served as controls. GW index (GWI) was obtained from pressure-strain loops composed from speckle tracking analysis indexed to brachial systolic blood pressure. Global constructive work (GCW) as the sum of positive work due to myocardial shortening during systole and negative work due to lengthening during isovolumic relaxation, global wasted work (GWW) as energy loss by myocardial lengthening in systole and shortening in isovolumic relaxation, and GW efficiency (GWE) as the percentage ratio of constructive work to the sum of constructive work and wasted work were measured after submaximal treadmill SE at the heart rate of 100–110 beats per minute (109±11 s after SE) using EchoPac software by blinded experienced echocardiographer. All patients were referred to coronary angiography after re-examination. Results 42 (44.7%) patients had lower GWI values than the lowest limit of GWI value in controls. These patients had significant reduction in GWI, compared with remaining 52 patients in whom GWI did not differ from those of controls (GWI 1897±112 mmHg% vs 2518±243 mmHg%, p&amp;lt;0.01). GCW, GWE and GWW were comparable between patients with or without reduced GWI (GCW 2283±107mmHg% vs 2321±110 mmHg%, p=NS; GWE 96.9±1.1% vs 97.4±1.2%, p=NS; GWW 57±3 mmHg% vs 53±4 mmHg%, p=NS). 28 (66.7%) of 42 patients with GWI reduction and 8 (15.0%) of 52 patients without GWI reduction had at least one vessel significant CAD. GWI had sensitivity, specificity, and accuracy in detection of CAD 78%, 76%, 77% respectively with 67% positive predictive value, and 85% negative predictive value. 29 (80.5%) patients out of 36 with significant CAD had concentric increase in LVMi compared with true negative SE patients (83±6 g/m2 vs 71±4 g/m2, p&amp;lt;0.01). GWI was the predictor of significant CAD (area under the curve 0.793). Conclusion GWI extends diagnostic power of conventional SE in detection of CAD, especially in patients with smaller LV cavity due to concentric hypertrophy when sensitivity of conventional SE is low. Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Committee of Sience at Ministry of Education of Republic of Armenia

Cardiac magnetic resonance and B-natriuretic peptide are superior prognostic tools to guideline-based echocardiography in asymptomatic patients with chronic severe aortic regurgitation

Abstract Background The optimal timing of intervention in patients with chronic aortic regurgitation (AR) is currently based on patient symptoms and echocardiography derived parameters. The sensitivity of this approach is suboptimal and late operation often results in irreversible myocardial damage. Purpose To determine the prognostic value of novel parameters in asymptomatic patients with chronic severe AR in optimal timing of aortic valve surgery. Methods Consecutive patients with chronic severe AR not indicated for surgery per the current guidelines were studied in a prospective design in 5 centers. Baseline examination consisted of B-natriuretic peptide (BNP) measurement, comprehensive echocardiography (ECHO) including 3-dimensional (3D) study with vena contracta area (VCA), and complex magnetic resonance (MRI) including regurgitant volume (RV), regurgitant fraction (RF), global myocardial work efficiency (GWE) and extracellular volume (ECV); all analyzed in core lab. All patients were followed every 6 months and the endpoint was disease progression defined as an indication for surgery. The perioperative myocardial biopsy was performed in all surgically treated patients for histological myocardial fibrosis quantification. Results In total, 129 patients were enrolled between 2015 and 2019, the endpoint occurred in 35 patients during a mean follow-up of 1044 days. Baseline clinical data did not differ between patients with disease progression (surgical group) and stable patients. Baseline BNP levels were higher in the surgical group (63 vs. 20, P&amp;lt;0.01) and a cut-off value of 30.4 ng/L was predictive of disease progression with AUC 0.75. None of the standard ECHO parameters of left ventricular (LV) size and function was predictive of the endpoint. Novel ECHO parameter 3D VCA was higher in the surgical group (32 vs. 26 mm2, P=0.037). All MRI parameters of LV size and function were predictive of disease progression (all P&amp;lt;0.02), except LV ejection fraction. MRI-derived RV (57 vs. 37 ml, P&amp;lt;0.01) and RF (46 vs. 34%, P&amp;lt;0.01) were identified as the strongest independent predictors of surgery. There was no difference in ECV between the surgical group and stable patients (24 vs. 24, P=0.81) despite a good correlation with histological quantification of myocardial fibrosis. Conclusions Standard ECHO parameters cannot reliably predict the need for surgery in asymptomatic aortic regurgitation patients. Baseline BNP levels above 30.4 ng/L predict disease progression. Novel imaging parameters – ECHO-derived 3D VCA and MRI-derived parameters of LV size and AR severity might be useful in optimal timing determination. Imaging markers and myocardial histology Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic

Key changes in indices of myocardial work in cardiometabolic disease states

Abstract Background Hypertension (HTN) and diabetes mellitus (DM) are prevalent cardiovascular disease states which have been shown to be associated with adverse cardiac remodelling and subclinical myocardial dysfunction. Myocardial work (MW) indices are novel non-invasive measures of left ventricular (LV) function. We aimed to characterise key differences in MW indices in patients with these conditions. Methods Outpatients with HTN and DM undergoing transthoracic echocardiography (TTE; 2016–2019) at our institution were assessed and compared to healthy controls. Only patients without cardiac disease with normal diastolic parameters on TTE were recruited. Patients with impaired LV function, cardiac ischaemia or arrhythmia, structural and valvular heart disease or poor-quality images were excluded. Recruited patients were stratified into 3 groups (Group1: Healthy Controls; Group 2: HTN; Group 3: HTN-DM). MW assessment was performed using GE E-95 EchoPac v2.2 system. Results Three hundred patients (57.3±17.4y, 51% female) were recruited. HTN and HTN-DM patients were associated with higher resting systolic blood pressure (SBP), indexed LV mass (LVMI), e' and E/e' compared to controls but no differences were noted in these parameters between HTN and HTN-DM. Global myocardial work index (GWI) was higher in HTN patients compared to Controls but not different compared to HTN-DM. Of interest, HTN-DM patients had higher global myocardial wasted work (GWW) and lower global myocardial work efficiency (GWE) compared to HTN patients and Controls. Conclusions MW indices may be a sensitive tool for the detection of subclinical changes in cardiac function in cardiometabolic disease states. Funding Acknowledgement Type of funding source: None

Transesophageal echocardiography in swine: evaluation of left and right ventricular structure, function and myocardial work

This study aimed to determine standard left (LV) and right ventricular (RV) transesophageal echocardiographic (TEE) measurements in swine. Additionally, global myocardial work index (GWI) was estimated using pressure-strain loops (PSL). A comprehensive TEE examination was conducted in ten anesthetized, intubated and mechanically ventilated healthy female German landrace swine, weighing 44 to 57 kg. For GWI calculation, we performed LV and RV segmental strain analysis and used invasively measured LV and RV pressure to obtain PSL. The GWI and further myocardial work indices were calculated from the area of the PSL using commercially available software. Furthermore, hemodynamic measurements were obtained using indwelling catheters. We obtained complete standardized baseline values for left and right ventricular dimensions and function. Biplane LV ejection fraction was 63 ± 7 % and the LV end-diastolic volume was 70.5 ± 5.9 ml. Tissue Doppler estimated peak tricuspid annular systolic velocity was 13.1 ± 1.8 cm/s. The Doppler estimated LV and RV stroke volume index were 75.6 ± 7.2 ml/m2 and 76.7 ± 7.8 ml/m2 respectively. Pulsed wave Doppler derived cardiac output correlated well with cardiac output estimated using the thermodilution method (7.0 ± 1.2 l/min vs. 7.0 ± 1.1 l/min, r = 0.812, p = 0.004). The LV global longitudinal strain was -21.3 ± 3.9 % and the RV global longitudinal strain was -15.4 ± 2.5 %. LV GWI was 1885(1281–2121) mmHg*% and 297 ± 62 mmHg*% for the RV. LV global myocardial work efficiency was 82.6 ± 4 % and 83(72–88) % for the RV. TEE offers sufficient morphological, functional and hemodynamic assessment of the heart in swine. Myocardial contractility and mechanics can be reliably evaluated with the non-invasive GWI derived from echocardiography without additional invasive measures.

P1575 Preserved myocardial work efficiency after transcatheter aortic valve implantation-induced left bundle branch block

Abstract Background Left bundle branch block (LBBB) frequently complicates transcatheter aortic valve implantation (TAVI), but may not induce classical mechanical dyssynchrony typically observed in heart failure patients with LBBB. Non-invasive estimated myocardial work by pressure strain-loops is a novel method for evaluation of left ventricular (LV) performance including loading conditions and identifies responders to cardiac resynchronization therapy. Assessment of myocardial work in TAVI-induced LBBB has, however, not been performed earlier. Purpose We aimed to evaluate myocardial performance in TAVI-induced LBBB by myocardial work. Methods Patients with severe aortic stenosis (AS) and normal ventricular conduction undergoing transfemoral TAVI were included. TAVI-induced LBBB was defined according to strict ECG criteria. In addition to standard echocardiographic parameters, we performed speckle tracking echocardiography (STE) within 2 days post procedure. Post-procedural myocardial work was estimated by commercially available software, combining LV strain by STE and a non-invasively estimated LV pressure curve. Peak systolic LV pressure was assumed to be equal to the sum of peak arterial cuff pressure and mean aortic valve pressure gradient. The proportion of constructive work relative to the sum of wasted and constructive work was expressed as myocardial work efficiency (Figure). A global work efficiency &amp;lt; 90 % was considered abnormal according to the recently published EACVI NORRE study. Results We included 109 consecutive patients undergoing TAVI (83 ± 7 years old, 54 % women, logistic Euroscore 16 ± 10) with severe AS (valve area 0.7 ± 0.2 cm2, mean transvalvular gradient 54 ± 18 mmHg), QRS duration 94 ± 10 ms, and a relatively preserved LV ejection fraction (54 ± 9%). New-onset LBBB was observed in 28 patients (26 %) after TAVI. Although post-procedural myocardial work efficiency was slightly better in patients who retained normal ventricular conduction than those with TAVI-induced LBBB (93.6 ± 2.5% vs 91.2 ± 3.4%, p = 0.004), both groups of patients had global myocardial work efficiency within the normal reference range. Conclusions Patients with TAVI-induced LBBB have preserved work efficiency despite gross electrical block satisfying strict ECG criteria. The reduced myocardial work efficiency in TAVI-induced LBBB was within the reference range of normal in the recently published EACVI NORRE study. The preservation of myocardial work in TAVI-induced LBBB may explain why LBBB as a complication to TAVI does not necessarily imply poor prognosis. Abstract P1575 Figure.

P1778 Preeclampsia is associated with reduced myocardial work efficiency during pregnancy

Abstract AIM Preeclampsia (PrE) is a systemic disorder unique to human pregnancy, which is characterised by hypertension and multiorgan involvement. It is associated with cardiac dysfunction with a reduction in global longitudinal strain (GLS) and long-term cardiovascular disease. The aim of this study is to evaluate the effects of the loading conditions on the GLS results utilising myocardial work (MW) a non-invasive assessment of left ventricular (LV) pressure strain loops. Methods We evaluated 41 pregnant women, aged between 18-40, at 28.4-40 (Mean 35) weeks of gestation and within one week of the diagnosis of PrE. 49 normotensive pregnant women (control) were matched for age and gestation. These patients were reassessed after six months postpartum. All patients underwent echocardiography for left ventricular indices and assessment with speckle tracking for global longitudinal strain (GLS%) and myocardial work indices - performed at both time points. Result PrE had a mean LV mass index (LVMi) of 14.53g.m2 higher than control (P value = 0.000) during pregnancy which normalised at six-months postpartum. There was a reduction in GLS between PrE and controls during pregnancy (p = 0.002) and this remained significant postpartum (p = 0.001). (Fig1) However, there was no change over time within each group. During pregnancy, peak global myocardial work efficiency (GWE%) in PrE was significantly lower than controls (p = 0.001) and no different six months postpartum (p = 0.169) (Fig2). In contrast, during pregnancy, myocardial work index (GWI mmHg) was significantly higher in PrE (p &amp;lt; 000) compared to control, but not in postpartum (p = 0.165) There was a significant change over time of GWI in both groups (p &amp;lt; 0.05) (Fig3). Conclusion During pregnancy and post-partum PrE patients show a reduction in GLS when compared to matched normotensive pregnant women. This finding is consistent with previous studies which suggests subclinical LV dysfunction in PrE. However, the GWI was significantly increased but reduced in efficiency (GWE). The GWI increase is likely a result of an increase in LV mass index. The hypertrophied LV allows the increase in work at the cost of a reduction in efficiency but normalises when the hypertrophy improves post-partum. Our study is the first to use myocardial work in PrE patients, which we believe provides a better assessment of cardiac adaptation post-partum and does not suggest long term subclinical LV dysfunction. Abstract P1778 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.

Resting Global Myocardial Work Derived from Non-Invasive LV Pressure-Strain Loops Discriminates between True Positive and False Positive Exercise Stress Echocardiography

Background: Non-invasive detection of obstructive CAD by exercise stress echocardiography (ESE) results in varied sensitivity and specificity due to qualitative interpretation of regional wall motion abnormalities (RWMA). This study sought to determine whether resting global myocardial work (MW) can differentiate between true (TP) and false positive (FP) ESE. Methods: Resting global MW was derived from non-invasive LV pressure-strain loops constructed from GLS and brachial SBP on 70 patients (mean age 56 ± 12 yrs; 31 males) referred for clinically indicated ESE (EF ≥55% with no evidence of RWMA). Indices of constructive work (positive work by myocardial shortening in systole including lengthening during isovolumic relaxation), wasted work (energy loss by myocardial lengthening in systole and shortening in isovolumic relaxation) and MW efficiency (percentage ratio of constructive and wasted work) were obtained. Coronary angiography was performed on those with a positive ESE (N = 18) to determine presence and/or severity of CAD (n = 10 significant CAD; n = 8 no significant CAD). Results: Resting global MW was significantly reduced (p < 0.05) in TP compared with FP ESE (1733 vs 2099 mmHg%). Global MW efficiency was the best differentiator and significantly reduced (p < 0.05) in TP vs FP ESE (94 vs 96%) due to significant reductions (p < 0.05) in constructive MW. 52 patients with a negative ESE showed a significantly higher (p < 0.05) resting GLS (18.6 vs 16.4%) and global MW (1971 vs 1733 mmHg%) compared to TP ESE. Conclusion: Non-invasive estimation of global MW may be a more sensitive tool than GLS to help distinguish between TP and FP ESE.