Myocardial work index: a glimmer of hope in COVID-19

Abstract

A 57-year-old man with no medical history presented to an outside hospital with the chief complaint of shortness of breath and cough. The patient tested positive for coronavirus disease 2019 (COVID-19). He presented to our institution 1 day later, and work-up included a chest X-ray that revealed patchy opacities in the bilateral mid to lower lung fields (Panel A) consistent with the recent diagnosis of COVID-19. He underwent transthoracic echocardiography to assess for COVID-19-related myocardial dysfunction. He was in normal sinus rhythm, and cuff blood pressure (BP) at the time of examination was 106/76 mmHg. Left ventricular ejection fraction (LVEF) was normal at 62% (Supplementary material online, Video S1), global longitudinal strain (GLS) was at the lower limits of normal at-18% (Panel B), global work index (GWI) was significantly reduced at 727 mmHg% (Panel C), and global work efficiency (GWE) was 95% (Panel D). The patient was discharged home and was symptom free at the 1-month follow-up. Cuff BP was 133/90 mmHg, and repeat echocardiography demonstrated a stable LVEF (Supplementary material online, Video S2), GLS (Panel E), and a significantly improved GWI of 1669 mmHg% (Panel F). GWE also remained relatively unchanged (Panel G). A difference in systolic BP of 27 mmHg between the two examinations is not enough to account for the drastic improvement in GWI. With no known underlying comorbidities contributing to the reduced GWI, we can hypothesize that myocardial work sets the stage as an even earlier indicator of COVID-19-induced myocardial dysfunction than reduced GLS and LVEF.

Subclinical Myocardial Dysfunction in Patients with Persistent Dyspnea One Year after COVID-19

“…The early detection of subclinical cardiac abnormalities could contribute to a better understanding of the extent of myocardial damage following COVID-19 which could lead to persistent dyspnea at mid- and long- term follow-up. The findings of the present study emphasize the potential incremental value of MW compared to standard TTE parameters to detect subclinical cardiac dysfunction in COVID-19 [ 42 ].…”

“…Similarly, in a retrospective study on hospitalized COVID-19 patients, a decrease in MW efficiency was associated with inflammation burden and in-hospital mortality [ 41 ]. Other small reports also showed reduced GWI in the presence of normal LVEF and GLS during the acute setting of the COVID-19 with an improved near to normal GWI after one month [ 42 ].…”

Myocardial Work: Methodology and Clinical Applications

“…These complications vary from acute myocardial infarction, myocarditis, pericarditis, and heart failure. There are case reports where patients with normal EF and GLS without any wall motion abnormalities showed significantly reduced GWI that recovered to near-normal in follow-up echo exams [ 27 ]. MW in this subgroup of patients again detected myocardial damage far before it could be with eyeball assessment, EF, or GLS.…”

Role of Cardiac Imaging Modalities in the Evaluation of COVID-19-Related Cardiomyopathy

“…With this method, myocardial strain is indexed by systolic blood pressure, in order to obtain a load-independent measure of systolic function. In patients with COVID-19, reduced myocardial work efficiency has been associated with increased mortality and may represent an early marker of LV systolic dysfunction [38,39].…”