The assessment of myocardial work(MW) using non-invasive pressure-strain loop analysis is a novel echocardiographic method that provides a more precise assessment of the cardiac performance, considering the left ventricular loading condition. By integrating various MW components such as index, efficiency, 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.

BACKGROUND: Coronary microvascular dysfunction (CMD) is involved in heart failure (HF) onset and progression, independently of HF phenotype and obstructive coronary artery disease. Invasive assessment of CMD might provide insights into phenotyping and prognosis of patients with HF. We aimed to assess absolute coronary flow, absolute microvascular resistance, myocardial perfusion, coronary flow reserve, and microvascular resistance reserve in patients with HF with preserved ejection fraction and HF with reduced ejection fraction (HFrEF). METHODS: Single-center, prospective study of 56 consecutive patients with de novo HF with nonobstructive coronary artery disease divided into HF with preserved ejection fraction (n=21) and HFrEF (n=35). CMD was invasively assessed by continuous intracoronary thermodilution and defined as coronary flow reserve <2.5. Left ventricular and left anterior descending artery–related myocardial mass was quantified by echocardiography and coronary computed tomography angiography. Myocardial perfusion (mL/min per g) was calculated as the ratio between absolute coronary flow and left anterior descending artery–related mass. RESULTS: Patients with HFrEF showed a higher left ventricular and left anterior descending artery–related myocardial mass compared with HF with preserved ejection fraction ( P <0.010). Overall, 52% of the study population had CMD, with a similar prevalence between the 2 groups. In HFrEF, CMD was characterized by lower absolute microvascular resistance and higher absolute coronary flow at rest (functional CMD; P =0.002). CMD was an independent predictor of a lower rate of left ventricular reverse remodeling at follow-up. In patients with HF with preserved ejection fraction, CMD was mainly due to higher absolute microvascular resistance and lower absolute coronary flow during hyperemia (structural CMD; P ≤0.030). CONCLUSIONS: Continuous intracoronary thermodilution allows the definition and characterization of patterns with distinct CMD in patients with HF and could identify patients with HFrEF with a higher rate of left ventricular reverse remodeling at follow-up.

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% CTRCD_mild, 18% CTRCD_mod), while 31 patients remained free of CTRCD (62% CTRCD_neg). Prior to chemotherapy MWI, MWE and CW were significantly lower in CTRCD_mod than in CTRCD_neg and CTRCD_mild. Overt cardiac dysfunction in CTRCD_mod at 6 months was accompanied by significant worse values in MWI, MWE and WW compared to CTRCD_neg and CTRCD_mild. 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.

Background: Transcatheter aortic valve replacement(TAVR) has shown clear survival benefits in severe aortic valve stenosis(AS). However, patients unable to recover left ventricle function remain at risk with poor long-term survival. This single-center prospective study aims to analyze the supplementary benefits of myocardial work(MW) assessment for baseline risk stratification in patients with severe AS referred for TAVR. Methods: A total of 110 patients with severe AS referred for TAVR were included in the study. Baseline ECG data, transthoracic echocardiographic(TTE) images and blood samples were obtained. The TTE examination was repeated one day and one month after valve replacement. The primary outcome of the study was a composite endpoint consisting of all-cause mortality and HF hospitalization. Results: During a mean follow-up period of 521 ± 343 days, 29patients(26.4 %) reached the composite endpoint. Baseline troponins, NT-proBNP, sST2, GWI and GCW showed statistically significant differences between groups. Patients with a baseline GWI<2323 mmHg% (sensitivity 0.63 and specificity 0.76)had significantly worse outcome following TAVR. A basic predictive model included QRS-length, TAPSE, LAVI and E/e’. The addition of biomarkers did not yield any further advantages whereas incorporating the GWI cut-off value of 2323 mmHg% significantly enhanced the predictive value. Although there were no significant changes in LVEF and GLS, all patients exhibited a significant reduction in GWI and GCW immediately after TAVR. Conclusion: Our findings provide evidence for the enhanced usefulness of MW analysis in the initial risk stratification of patients with severe AS referred for TAVR. Specifically, a baseline GWI<2323 mmHg% demonstrates an independent predictor associated with increased incidence of all-cause mortality and HF hospitalization following TAVR.

Background: The Mustard and Senning operations for dextro-transposition of the great arteries (D-TGA) establish a biventricular physiology with a subaortic right ventricle (sRV). While prolonged QRS has been associated with worse prognosis in these patients, current echocardiographic tools fall short in adequately assessing the (mal) performance and function decline of the sRV during follow-up. The present study is the first to characterize Myocardial Work (MW) indices of the sRV in D-TGA patients after Mustard/Senning repair. Methods and results: All adult D-TGA patients at follow-up in the University Hospital of Leuven between 2018 and 2022 were screened for inclusion. We retrospectively collected the most recent electrocardiogram parameters, 2D echocardiographic images and serum biomarkers' values. Offline calculations of MW indices were performed. We established correlations between all variables and categorized patients into QRS= 120 ms for further analysis. A total of 51 D-TGA patients were included (13 Mustard, 33 male, 39 +/- 6 years). QRS duration increased with age and was correlated with sRV dimensions and serum levels of troponins (R = 0.42, p < 0.01) and NT-proBNP (R = 0.31, p = 0.03). However, no significant correlation was found between QRS duration and intraventricular desynchrony or conventional functional echocardiographic parameters. QRS prolongation was associated with a deterioration in septal, but not lateral, MW parameters. Patients with QRS >= 120 ms had significantly larger ventricles and higher levels of troponins and NT-proBNP. Conclusion: QRS prolongation after Mustard/Senning repair is linked to ventricular dilatation and worse performance, particularly affecting the septal wall. Global and regional MW analysis may be useful to assess the subclinical deterioration of sRV function.

Funding Acknowledgements: Type of funding sources: Foundation. Main funding source(s): Cardiovascular Research Center Aalst, (Aalst, Belgium) Introduction: Breast cancer patients receiving anthracyclines are particularly prone to develop cancer therapeutics-related cardiac dysfunction (CTRCD). Early detection of cardiotoxicity onset is required for optimal timing of cardio protection treatment. The latest guidelines consider a relative reduction of 15% in global longitudinal strain (GLS) from baseline as risk for cardiotoxicity. Nevertheless, the more recent Myocardial Work Index (MWI) offers a load-independent tool for detection of subclinical heart failure (HF). Data in cancer patients are still scarce. Purpose: This study analyses the predictive value of MWI for cardiotoxicity diagnosis after 6 months chemotherapy. Methods: The study population consists of breast cancer patients referred for chemotherapy with anthracyclines and taxanes. Patients with a history of HF previous to chemotherapy or depressed LV function at baseline were excluded. Echocardiography was performed before onset of the chemotherapy (baseline) and after 6 months follow-up. LVEF, GLS and MWI were assessed offline using EchoPAC software. The values at baseline and 6 months follow-up were pairwise compared to detect subclinical cardiac dysfunction. Mean LVEF, GLS and MWI at baseline were taken as cut-off value to compare the predictive value of each parameter. Moreover, patients were categorized in one group with GLS reduction >15% (Group 1) and one group with GLS reduction 15% showed significant lower MWI after 6 months (1626 ± 344 mmHg vs 2116 ± 334 mmHg, p = 0.003, Figure 1). Conclusions: At 6 months follow up, a decline of the LV systolic function as side effect of chemotherapy can be seen. In comparison to LVEF and GLS, MWI shows the best predictive value for development of early cardiotoxicity. Further studies are warranted to better understand the role of MWI in predicting CTRCD and its clinical relevance. Abstract Figure. Change in MWI