Few data exist regarding the effect of image quality on measurements of two-dimensional longitudinal strain (2DLS). In the 2DLS for Diagnosing Chest Pain in the Emergency Room (2DSPER) multicenter study, 2DLS was not useful for ruling out acute coronary syndromes (ACS) in the emergency department (ED). The aim of this substudy was to determine the effect of 2D image quality on the diagnostic accuracy of 2DLS for ACS. We reviewed apical views used for 2DLS analysis in all 605 patients included in the 2DSPER study. Studies with the best image quality (HighQ, n = 177), were compared to the lower quality group (LowQ, n = 428). Abnormal 2DLS was defined as PSS20% > − 17% (PSS20% being the peak left ventricular systolic strain value identifying the 20% worst strain values). Global longitudinal strain (GLS) and PSS20% were significantly worse in LowQ compared to HighQ patients. LowQ independently predicted abnormal 2DLS (OR 1.9, 95% CI 1.3–2.9, P = 0.003). The sensitivity of PSS20% > − 17% for ACS was 85% for LowQ vs. 73% for HighQ (P = 0.2), specificity 22% vs. 38% (P < 0.0001) and overall accuracy 29% vs. 44% (P = 0.0004). Despite better overall accuracy in the HighQ group there was no significant difference between the receiver operating characteristic curves of either GLS or PSS20% in the two groups and abnormal 2DLS did not predict ACS even in HighQ patients (OR 1.7, 95% CI 0.7–4.3, P = 0.3). LowQ echo is associated with worse 2DLS. Abnormal 2DLS was not clinically useful for excluding ACS in the ED even in patients with optimal 2D image quality. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01163019.
- Acute coronary syndrome
- Image quality
- Longitudinal strain
- Speckle tracking echocardiography
- Two-dimensional echocardiography