BACKGROUND: Diagnosing pericardial effusion is critical for optimal patient care. Typically, clinicians use physical examination findings and historical features suggesting pericardial effusion to determine which patients require echocardiography. The diagnostic characteristics of these tools are not well described. The objective of this study is to determine the prevalence of historical features and sensitivity of clinical signs to inform clinicians when to proceed with echocardiogram. METHODS: A retrospective review of point-of-care echocardiograms performed over a two and a half year period in two emergency departments were reviewed for the presence of a pericardial effusion. Patient charts were reviewed and abstracted for presenting symptoms, historical features and clinical findings. The prevalence of presenting symptoms and historical features and the sensitivity of classic physical examination findings associated with pericardial effusion and tamponade were determined. RESULTS: One hundred and fifty-three patients with pericardial effusion were identified. Of these patients, the most common presenting complaint was chest pain and shortness of breath. Patients had no historical features that would suggest pericardial effusion in 37.5% of cases. None of the patients with pericardial effusion or pericardial tamponade had all of the elements of Beck's triad. The sensitivity of Beck's triad was found to be 0 (0%–19.4%). The sensitivity for one finding of Beck's triad to diagnose pericardial tamponade was 50% (28.0%–72.0%). CONCLUSION: History and physical examination findings perform poorly as tests for the diagnosis of pericardial effusion or pericardial tamponade. Clinicians must liberally evaluate patients suspected of having a pericardial effusion with echocardiography.