Rapid Fire Abstract session: clinical applications of speckle tracking and tissue Doppler imaging

Background: Echocardiographic two-dimensional left ventricular (LV) longitudinal strain (2DS) analysis has been suggested as a useful tool for detection of acute coronary syndromes (ACS). Our aim was to determine whether 2DS analysis could accurately rule out ACS in the emergency department (ED). Methods: We prospectively enrolled 700 patients from 11 hospitals presenting to the ED with chest pain (CP) and suspected ACS but without diagnostic ECG or troponin elevation. An echocardiogram was performed within 24 hours of CP. Following a standard in-hospital evaluation a final diagnosis of ACS or no-ACS was made, and patients were followed for 6 months for MACE. 2DS analysis was performed in a core lab using designated software. Histograms of peak LV systolic strain (PSS) were generated and the value identifying the 20% worst strain values (PSS20%) was determined. A pre-specified value of > -17% PSS20% was used to define abnormal 2DS. Results: 2DS analysis was available for 605 patients (mean age 58 ± 9 y, 70% males), of which 74 (12.2%) had ACS. Coronary anatomy was available in 67 (91%) patients with ACS and 95 (17.9%) patients without ACS. During follow-up (92% complete) MACE occurred in 4 (5.8%) patients with and in 3 (0.6%) without ACS. Abnormal 2DS was present in 60 patients with ACS (sensitivity 81%, negative predictive value 91%), but also in 391 patients without ACS (specificity 26%, positive predictive value 13%). Based on 2DS analysis alone, only 140 patients (23%) could have been safely discharged from the ER whereas 14 patients (2.3%) with ACS would have been missed and 391 (65%) would have had an unnecessary work-up. Receiver operating characteristic curves showed an area under curve of 59% for PSS20% and 60% for global strain (p=0.3). Independent predictors of abnormal 2DS were male gender (OR 2.93 [95% CI 1.90-4.52], p<0.0001), body mass index (OR 1.09 [1.04-1.14], p=0.0007), heart rate during echo (OR 1.03 [1.01-1.05], p<0.002) and tissue Doppler mean e’ (septal+lateral) (OR 0.83 [0.76-0.92], p=0002). ACS did not predict abnormal 2DS. Conclusion: In this large multicenter prospective study 2DS was not a useful tool to rule out ACS in the ED due to a high false positive rate.