Introduction: Transthoracic bedside echocardiography (TTE) in the emergency department is recommended in patients with suspected myocardial infarction (MI), who do not qualify for early discharge using accelerated protocols. The prognostic value of routine echocardiographic parameters like wall motion abnormalities in patients with suspected MI, has not been evaluated so far. Therefore, our aim was to analyze whether TTE is a suitable risk stratification tool in patients presenting with suspected MI. 

Methods: In a prospective cohort study 2,719 patients presenting to the emergency department with symptoms indicate of MI were recruited. Among these patients, 2,163 (79,6%) had available TTE and were therefore included in the current analysis. We assessed systolic left ventricular (LV-)function, wall motion abnormalities and high-grade valvular defects. To test the prognostic value of TTE, patients were further stratified by dynamic and non-dynamic high-sensitivity troponin I (hs-TnI) concentrations in serial measurements. Patients were followed up for up to 5 years to assess all-cause mortality and major adverse cardiac events (MACE), composited of cardiac rehospitalization, revascularization, myocardial infarction and death. Kaplan Meier survival curves were created and compared using the log rank test. 

Results: Among 2,163 patients 63.9% were male and the mean age was 64 years. Acute myocardial infarction was present in 383 (17.7%). A reduced systolic LV-function was detected in 20.1%, 21.1% had wall motion abnormalities, composed of 9.3% with akinesia and 11.8% with hypokinesia. High-grade valvular defects were present in 8.2%. In patients with any pathological finding in TTE the rate of MACE was significantly higher than in patients without pathological findings (p<0.001, Figure 1A): After 5 years, MACE occurred in 323 (30.05%) of patients with a normal TTE, whereas 349 (58.7%) patients with at least one pathology developed MACE after 5 years. Overall mortality as a single component of the combined endpoint occurred in 87 (8.73%) patients with a normal TTE, while in patients with pathologies 166 (29.8%) had died (p<0.001).

Patients with non-dynamic hs-TnI and a normal TTE had superior outcome compared to patients with dynamic troponin with and without pathologies in TTE (Figure 1B). Interestingly, patients with non-dynamic troponin and TTE pathologies had the worst outcome. This was true for the combined MACE endpoint, as well for overall mortality alone. Patients with a pathology in TTE had a significantly increased mortality after 5 years regardless of troponin dynamics: Among patients without a pathological TTE and non-dynamic hs-TnI, 65 (8.15%) died and with troponin dynamics 15 (10.96%) died. While with echocardiographic pathologies, 92 (32.28%) patients with non-dynamic troponin died and of those with dynamics 62 (28.62%).

Conclusion: We describe the value of TTE as prognostic tool in patients with suspected MI and found that patients with any pathologies in TTE were at substantially higher cardiovascular risk compared to patients without pathologies.