Clinical Investigations
Normal Values for Global Left Ventricular Myocardial Work
Normal Ranges of Global Left Ventricular Myocardial Work Indices in Adults: A Meta-Analysis

https://doi.org/10.1016/j.echo.2021.11.010Get rights and content

Highlights

  • Echocardiographic reference ranges for indices of MW were established.

  • Gender significantly contributed to variations in normal values of MW.

  • MW indices had excellent and good intra- and interobserver reproducibility.

Background

Recent studies have demonstrated that left ventricular myocardial work (MW) is incremental in diagnosis and prognostication compared with left ventricular ejection fraction and myocardial strain. The authors performed a meta-analysis of normal ranges of noninvasive MW indices including global work index, global constructive work, global wasted work, and global work efficiency and determined confounders that may contribute to variance in reported values.

Methods

Four databases (PubMed, Scopus, Embase, and the Cochrane Library) were searched through January 2021 using the key terms “myocardial work,” “global constructive work,” “global wasted work,” “global work index,” and “global work efficiency.” Studies were included if the articles reported LV MW using two-dimensional transthoracic echocardiography in healthy normal subjects, either in a control group or comprising the entire study cohort. The weighted mean was estimated by using the random-effect model with a 95% CI. Heterogeneity across included studies was assessed using the I2 test. Funnel plots and the Egger regression test were used to assess potential publication bias.

Results

The search yielded 476 articles. After abstract and full-text screening, we included 13 data sets with 1,665 patients for the meta-analysis. The reported normal mean values of global work index and global constructive work among the studies were 2,010 mm Hg% (95% CI, 1,907-2,113 mm Hg%) and 2,278 mm Hg% (95% CI, 2,186-2,369 mm Hg%), respectively. Mean global wasted work was 80 mm Hg% (95% CI, 73-87 mm Hg%), and mean global work efficiency was 96.0% (95% CI, 96%-96%). Furthermore, gender significantly contributed to variations in normal values of global work index, global wasted work, and global work efficiency. No evidence of significant publication bias was observed.

Conclusions

In this meta-analysis, the authors provide echocardiographic reference ranges for noninvasive indices of MW. These normal values could serve as a reference for clinical and research use.

Section snippets

Search Strategy

Our systematic review and meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline.10 Four databases (Embase, PubMed, Scopus, and the Cochrane Library) were systematically searched for the key terms “myocardial work,” “global constructive work,” “global wasted work,” “global work index,” and “global work efficiency” by two coauthors (V.T.T. and H.P.) under the guidance of a librarian trained in performing systematic reviews;

Study Selection

A total of 1,174 titles were located using the search strategy from four databases (PubMed, n = 390; Scopus, n = 390; Embase, n = 362; Cochrane, n = 32; Figure 2). After excluding duplicates (n = 698), 476 articles were screened for relevance. We further excluded articles unrelated to the topic or abstracts without text, reviews, articles not in English, and studies not in humans. Additionally, searching the bibliographies did not reveal any additional studies. Only 13 studies with 1,665

Discussion

To the best of our knowledge, this is the first meta-analysis to provide pooled estimates for echocardiographic values of noninvasive global MW (GMW) among healthy subjects. In establishing reference ranges and the potential impacts of potential confounders on GMW values, our study provides a framework for future comparison of study groups to normal control subjects.

LVEF has become a cornerstone in contemporary clinical practice, guiding patient management and prognosis in a variety of clinical

Conclusion

In this meta-analysis, we provide echocardiographic reference ranges for noninvasive indices of MW. These normal values could served as a reference for clinical and research use.

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      Citation Excerpt :

      Second, the authors assessed the mean or median values ± SD or IQR, as appropriate, prebypass at timepoint T1 by TEE for GWI and GCW of 1,224 ± 312 mmHg% and 1,460 ± 312 mmHg%, respectively, and observed mean values of 143 mmHg% (IQR 99-183) for GWW and 89% (IQR 85-92) for GWE. Compared to published TTE-assessed reference values of healthy, awake, and spontaneously breathing individuals from the NORRE study33 and a recent meta-analysis from Truong et al.,34 the pre-bypass values assessed by TEE in the authors’ patient population here seemed to be reduced. Manganaro et al.33 reported mean values of 1,896 ± 308 mmHg% for GWI, 2,232 ± 331 mmHg% for GCW, 78.5 mmHg% (53-122) for GWW and a GWE of 96% (94-97), analyzed in 226 healthy, awake, and spontaneously breathing subjects.

    View all citing articles on Scopus

    Drs Truong, and Vo contributed equally to this report.

    Thomas H. Marwick, MBBS, PhD, MPH, MD, served as guest editor for this report.

    Conflicts of interest: None.

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