Changes in Global Left Ventricular Myocardial Work Indices and Stunning Detection 3 Months After ST-Segment Elevation Myocardial Infarction.

Global left ventricular (LV) myocardial work (MW) indices (GLVMWI) are derived from speckle tracking echocardiographic strain data in combination with non-invasive blood pressure measurements. Changes in global work index (GWI), global constructive work (GCW), global wasted work (GWW) and global work efficiency (GWE) after ST-segment elevation myocardial infarction (STEMI) have not been explored. The aim of present study was to assess the evolution of GLVMWI in STEMI patients from baseline (index infarct) to 3 months' follow-up. Three-hundred and fifty patients (265 men; mean age 61 ± 10 years) with STEMI treated with primary percutaneous coronary intervention (PCI) and guideline-based medical therapy were retrospectively evaluated. Clinical variables, conventional echocardiographic measures and GLVMWI were recorded at baseline within 48 hours post-primary PCI and 3 months' follow-up. LV ejection fraction (from 54 ± 10% to 57 ± 10%, p < 0.001), GWI (from 1449 ± 451 mm Hg% to 1953 ± 492 mm Hg%, p < 0.001), GCW (from 1624 ± 519 mm Hg% to 2228 ± 563 mm Hg%, p < 0.001) and GWE (from 93% (interquartile range (IQR) 86%-95%) to 95% (IQR 91%-96%), p < 0.001) improved significantly at 3 months' follow-up with no significant difference in GWW (from 101 mm Hg% (IQR 63-155 mm Hg%) to 96 mm Hg% (IQR 64-155 mm Hg%); p = 0.535). On multivariable linear regression analysis, lower values of troponin T at baseline, increase in systolic blood pressure and improvement in LV global longitudinal strain were independently associated with higher GWI and GCW at 3 months' follow-up. In conclusion, the evolution of GWI, GCW and GWE in STEMI patients may reflect myocardial stunning, whereas the stability in GWW may reflect permanent myocardial damage and the development of non-viable scar tissue.

Global Left Ventricular Myocardial Work Efficiency and Long-Term Prognosis in Patients After ST-Segment-Elevation Myocardial Infarction.

BACKGROUND: Left ventricular (LV) global longitudinal strain has demonstrated incremental prognostic value over LV ejection fraction in patients with ST-segment-elevation myocardial infarction. However, LV global longitudinal strain does not take into consideration the effect of afterload. Novel speckle-tracking echocardiographic indices of myocardial work integrate blood pressure measurements (afterload) with LV global longitudinal strain. The present study aimed to investigate the prognostic value of global LV myocardial work efficiency (GLVMWE; reflecting LV performance) obtained from pressure-strain loops with echocardiography in patients with ST-segment-elevation myocardial infarction. METHODS: A total of 507 ST-segment-elevation myocardial infarction patients (mean age, 61±11 years; 76% men) were retrospectively analyzed. LV ejection fraction and GLVMWE were measured by transthoracic echocardiography within 48 hours of admission. GLVMWE was defined as the ratio of constructive work divided by the sum of constructive and wasted work in all LV segments and expressed as a percentage. Spline curve analysis was used to define the association between reduced GLVMWE and all-cause death. RESULTS: After a median follow-up of 80 months (interquartile range, 67-97 months), 40 (8%) patients died. Patients with reduced GLVMWE (<86%) showed higher cumulative rates of all-cause mortality (17.5% versus 4.7%; log-rank P<0.001) in comparison with patients with preserved GLVMWE (≥86%). Reduced GLVMWE (<86%) showed an independent association with all-cause mortality (hazard ratio, 3.167 [95% CI, 1.679-5.972]; P<0.001). CONCLUSIONS: Reduced GLVMWE (<86%) measured by transthoracic echocardiography within 48 hours of admission in ST-segment-elevation myocardial infarction patients is associated with worse long-term survival.

Left ventricular myocardial work in the culprit vessel territory and impact on left ventricular remodelling in patients with ST-segment elevation myocardial infarction after primary percutaneous coronary intervention.

AIMS: Adverse left ventricular (LV) remodelling after ST-segment elevation myocardial infarction (STEMI) is associated with poor outcome. Global and regional LV myocardial work (LVMW) derived from speckle tracking echocardiographic strain data in combination with non-invasive blood pressure recordings could provide information for prediction of LV remodelling after STEMI. The aim of the study was to assess the predictive value of global and regional LVMW for LV remodelling before discharge in patients with STEMI. METHODS AND RESULTS: Three-hundred and fifty STEMI patients treated with primary percutaneous coronary intervention (PCI) were included [265 men (76%), mean age: 61 ± 10 years]. Clinical variables, conventional echocardiographic parameters, global and regional measures of myocardial work index (MWI), and myocardial work efficiency were recorded before discharge. The primary endpoint was early LV remodelling defined as increase in LV end-diastolic volume (LVEDV) ≥20% at 3 months after STEMI. Eighty-seven patients (25%) showed early LV remodelling. The global and regional LVMW in the culprit territory were significantly lower in patients with early LV remodelling. Peak troponin I (OR 1.109, 95% CI 1.046-1.177; P = 0.001), LVEDV (OR 0.972, 95% CI 0.959-0.984; P < 0.001) and regional MWI in the culprit vessel territory (OR 0.602, 95% CI 0.383-0.945; P = 0.027) were independently associated with early LV remodelling. CONCLUSION: In STEMI patients treated with primary PCI and optimal medical therapy, the regional cardiac work index in the culprit vessel territory before discharge is independently associated with early adverse LV remodelling.

Noninvasive Myocardial Work Indices 3 Months after ST-Segment Elevation Myocardial Infarction: Prevalence and Characteristics of Patients with Postinfarction Cardiac Remodeling.

BACKGROUND: Assessment of left ventricular (LV) remodeling after ST-segment elevation myocardial infarction (STEMI) is pivotal for patient management. Noninvasive myocardial work indices obtained from echocardiography-derived strain-pressure loops provide a new tool that permits characterization of LV mechanics. We aimed at characterizing myocardial work indices in patients with LV remodeling after STEMI versus patients without remodeling. METHODS: Six-hundred STEMI patients were retrospectively analyzed (456 men, mean age: 61 ± 11 years) and divided according to the presence of LV remodeling 3 months after the index admission (≥20% increase in LV end-diastolic volume). Noninvasive myocardial work indices were measured at 3 months after STEMI. RESULTS: LV remodeling was observed in 150 patients (25%) who showed more impaired global myocardial work indices compared with their counterparts: work index (1,708 ± 522 mm Hg% vs 1,979 ± 450 mm Hg%; P < .001), constructive work (1,941 ± 598 mm Hg% vs 2,272 ± 519 mm Hg%; P < .001), and work efficiency (92% [range 88%-96%] vs 95% [range 93%-96%]; P < .001). In addition, patients with LV remodeling had significantly increased wasted work (116 mm Hg% [range 73-184 mm Hg%] vs 91 mm Hg% [range 61-132 mm Hg%]; P < .001). The frequency of impaired global work index, constructive and work efficiency, and increased wasted work was significantly higher among patients with LV remodeling compared with their counterparts: 21.3%, 34.7%, 34.7%, and 14.0%, respectively, versus 5.3%, 9.6%, 8.9%, and 4.9%, respectively (P < .001). CONCLUSIONS: At 3-month follow-up after STEMI, patients with LV remodeling revealed more impaired myocardial work indices compared with patients without LV remodeling. The prevalence of impaired myocardial work indices was higher among patients with LV remodeling compared with patients without.

Left ventricular remodelling and change in left ventricular global longitudinal strain after cardiac resynchronization therapy: prognostic implications.

AIMS: Cardiac resynchronization therapy (CRT) can reduce left ventricular end-systolic volume (LVESV), and a decrease of ≥15% is defined as a response. CRT can also improve LV global longitudinal strain (GLS). Changes in LVESV and LV GLS are individually associated with outcome post-CRT. We investigated LVESV and LV GLS changes and prognostic implications of improvement in LVESV and/or LV GLS, compared with no improvement in either parameter. METHODS AND RESULTS: Baseline and 6-month echocardiograms were analysed from CRT recipients with heart failure. LV reverse remodelling was defined as a ≥15% reduction in LVESV at 6 months post-CRT. A ≥5% absolute improvement in LV GLS was defined as a change in LV GLS. A total of 1185 patients were included (mean age 65 ± 10 years, 73% male), and those with an improvement in LVESV and LV GLS (n = 131, 11.1%) had significantly lower mortality compared with other groups. On multivariable analysis, an improvement in both LVESV and LV GLS [hazard ratio (HR): 0.47; 95% confidence interval (CI): 0.31-0.71; P < 0.001] or an improvement in either LVESV or LV GLS (HR: 0.57; 95% CI: 0.47-0.71; P < 0.001) were independently associated with better prognosis, compared with no improvement in either parameter. CONCLUSION: Either a reduction in LVESV and/or an improvement in LV GLS at 6 months post-CRT are independently associated with improved long-term prognosis, compared with no change in both LVESV and LV GLS. This supports the use of LV GLS as a meaningful parameter in defining CRT response.

Prognostic implications of global, left ventricular myocardial work efficiency before cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) restores mechanical efficiency to the failing left ventricular (LV) by resynchronization of contraction. Global, LV myocardial work efficiency (GLVMWE) can be quantified non-invasively with echocardiography. The prognostic implication of GLVMWE remains unexplored, and we therefore related GLVMWE before CRT to long-term prognosis. METHODS AND RESULTS: Data were analysed from an ongoing registry of patients with Class I indications for CRT. GLVMWE was defined as the ratio of constructive work in all LV segments, divided by the sum of constructive and wasted work in all LV segments, as a percentage. It was derived from speckle tracking strain echocardiography and non-invasive blood pressure measurements, taken pre-CRT. Patients were dichotomized according to baseline, median GLVMWE [75%; interquartile range (IQR) 66-81%]. A total of 153 patients (66 ± 10 years, 72% male, 48% ischaemic heart disease) were analysed. After a median follow-up of 57 months (IQR 28-76 months), 31% of patients died. CRT recipients with less efficient baseline energetics (GLVMWE <75%) demonstrated lower event rates than patients with more efficient baseline energetics (GLVMWE ≥75%) (log-rank test, P = 0.029). On multivariable analysis, global LV wasted work ratio <75% pre-CRT was independently associated with a decreased risk of all-cause mortality (hazard ratio 0.48, 95% confidence interval 0.25-0.92; P = 0.027), suggesting that the potential for improvement in LV efficiency is important for CRT benefit. CONCLUSION: GLVMWE can be derived non-invasively from speckle tracking strain echocardiography and non-invasive blood pressure recordings. A lower GLVMWE before CRT is independently associated with improved long-term outcome.