Scoping Review of Early Transthoracic Echocardiography for Diagnosis and Prognosis After Cardiac Arrest

Introduction: Transthoracic echocardiography (TTE) is commonly performed early after resuscitation from cardiac arrest (CA). The ability of early TTE to differentiate cardiac from non-cardiac causes of CA or to inform patient outcomes has not been systematically reviewed. Methods: We reviewed MEDLINE, EMBASE, and CENTRAL databases from inception to December 2020 for studies that assessed adult recipients of TTE after resuscitation from non-traumatic CA. Studies were included if TTE was obtained early (<72 hours) after spontaneous return of circulation and reported either 1) their diagnostic accuracy for causes of the CA or 2) survival and neurologic outcomes. Diagnostic endpoints also included regional wall motion abnormalities (RWMA) to ascertain possible acute myocardial infarction (AMI) as the etiology of CA. Prognostic endpoints included TTE parameters and their association with survival to hospital discharge and neurologic outcomes. Results: Of 2518 articles screened, 12 (0.5%) studies met inclusion criteria, representing 1570 unique patients. Meta-analysis was not possible due to missing data and study heterogeneity. Five studies were included in diagnosis review and nine in the prognosis review. No studies reported the diagnostic accuracy of TTE for AMI, although in 3 of 5 studies RWMA were associated with AMI in 53-83% of patients. Reduced left ventricular ejection fraction was reported in 8 studies but was not associated with survival (Figure) or neurologic outcomes (n=4). Only high mitral inflow E/e’ ratio (n=1) and decreased right ventricular function (RVD; n=2) were associated with worse survival. Conclusion: This scoping review highlights the limited available data on the utility of early TTE after CA. Assessment of left and right ventricular function and other parameters by TTE is feasible, but further research is necessary to determine their diagnostic and prognostic value after CA.