Abstract
Background
Left ventricular (LV) functional assessment is of imminent value after ST-elevation infarction (STEMI). LV longitudinal strain (LS) evaluates ventricular function on a myocardial level. Feature Tracking (FT) assesses strain from cine cardiac magnetic resonance (CMR) images. It is unknown how LV FT Regional LS (RLS) and Global LS (GLS) changes between the sub-acute and chronic phase after STEMI compared to controls and how GLS and RLS are related to culprit vessel (LAD, LCX or RCA) and infarction size (IS).
Aims
To assess 1) GLS with FT after 2–6 days (sub-acute) and 6 months (chronic phase) after STEMI compared with controls, 2) if GLS changes between sub-acute and chronic phase, and 3) the relationship between GLS and RLS to IS and infarct location.
Methods and results
Seventy-seven patients underwent CMR 2–6 days and 6 months after STEMI as well as 27 healthy controls. GLS was impaired at the sub-acute (−8.9±2.3%) and chronic phase (−14.3±2.9%) compared to controls (−18.4±2.4%; p<0.001 for both). GLS improved between the sub-acute and chronic phase (p<0.001). GLS correlated to IS (R=0.47 sub-acute; 0.49 chronic, p<0.001). LAD infarctions had lowest GLS and largest IS. RLS was more impaired in the culprit vessel territory compared to remote. RLS in the RCA region was lower for LAD than RCA infarctions. RLS was impaired in all 6 wall-regions in LAD infarctions, while LCX and RCA infarctions had preserved RLS in remote myocardium.
Global Longitudinal Strain (GLS)
Conclusion
GLS is impaired after STEMI and improves, but do not normalize, to the chronic phase. GLS is only moderately correlated to IS, indicating that other factors and co-morbidities are important to determine ventricular function. Even though RLS is most impaired in the affected region, remote regions can be substantially impaired in LAD-infarctions, why it would be difficult to pinpoint the culprit vessel based on RLS.