Left ventricular (LV) mechanical dispersion (LVMD), measured with speckle-tracking echocardiography (STE) after ST-segment elevation myocardial infarction (STEMI), has been proposed as a measurement of regional heterogeneity of myocardial contraction and may reflect changes in the myocardial structure (e.g., fibrosis or edema). Further insight into this parameter may aid in the risk stratification of STEMI patients.

A total of 1,000 STEMI patients (77% male, 60 ± 12 years) treated with primary percutaneous coronary intervention were retrospectively analyzed. The LVMD was assessed with two-dimensional STE within 48 hours following the index infarction. Patients were followed for the occurrence of all-cause mortality.

After a median follow-up of 117 months, 229 (23%) patients died. Nonsurvivors showed worse LV ejection fraction (43% ± 10% vs 48% ± 9%; P < .001) and global longitudinal strain (–12.0% ± 3.5% vs –14.2% ± 3.5%; P = .001) and prolonged LVMD (63 [interquartile range, 50-85] msec vs 52 [interquartile range, 42-63] msec; P < .001) compared with survivors. Increasing age, systolic blood pressure, and heart rate at discharge as well as diabetes mellitus, anterior STEMI, TIMI flow < 2, less usage of angiotensin converter enzyme inhibitors or angiotensin receptor blockers, and impaired LV global longitudinal strain were independently associated with more prolonged LVMD. On multivariable analysis, prolonged LVMD was independently associated with increased risk of all-cause mortality (hazard ratio = 1.012; 95% CI, 1.005-1.018; P = .001) and had incremental value for all-cause mortality over clinical and echocardiographic parameters.

In contemporary STEMI patients, prolonged LVMD was associated with various clinical and echocardiographic parameters. Prolonged LVMD was associated with worse long-term outcome.

The association between LVMD and all-cause mortality in patients after STEMI. (A) Example of LVMD in a survivor patient after STEMI. The culprit vessel was the RCA, and the LVEF was 55%. (B) Example of LVMD in a nonsurvivor patient after STEMI. The culprit vessel was the RCA, and the LVEF was 30%. (C) Prediction of all-cause mortality across a wide range of LVMD values. This is plotted as a fitted spline model with overlaid CIs. The dashed black lines represent 95% CIs. The green dotted line marks the predicted HR at 1, and the dotted red line the value of LVMD above which there is an excess of mortality. (D) Kaplan-Meier curves for all-cause mortality according the median LVMD. Patients with prolonged LVMD (red dotted line) showed worse outcome when compared with their counterparts (green line). RCA, Right coronary artery.