Logo: to the web site of Uppsala University

This thesis investigates the accuracy and prognostic utility of left ventricular ejection fraction (LVEF) and global longitudinal strain (GLS) in acute coronary syndrome (ACS), analyzing data from Swedish myocardial infarction patients across four studies. The first paper evaluated the accuracy and reliability of LVEF recorded in the SWEDEHEART registry. Although good agreement was observed using Gwet’s weighted coefficient, unweighted metrics showed moderate consistency particularly for subnormal LVEF (<50%) with SWEDEHEART values tending to underestimate LVEF compared to the reference method. This highlights the need for caution when interpreting LVEF data from the years of inclusion (2008-2014).

In the second study, GLS was examined as a potential metric to improve risk prediction in ACS beyond LVEF. Although GLS was independently predictive of adverse outcomes, its additional prognostic value over LVEF for differentiating patients at risk was limited, particularly when systolic function was normal or mildly reduced. The third study reassessed LVEF and GLS one year post-myocardial infarction, finding that changes in GLS may offer improved prognostic insights in selected patients beyond initial LVEF and GLS values. Patients with improved systolic function showed comparable outcomes to those with stable normal function, while a small subset with deteriorating GLS faced elevated risk of heart failure (HF) hospitalization.

The final study explored the impact of adding LVEF and GLS to the GRACE 2.0 score for mortality risk stratification. Neither LVEF nor GLS significantly enhanced risk discrimination whereas the biomarker GDF-15 did improve predictive accuracy when combined with GRACE 2.0, suggesting that in ACS populations with predominantly normal ejection fraction, comorbidities and age, rather than myocardial dysfunction, influence mortality risk.