Dyspnea is a common symptom among emergency department (ED) patients. The differential diagnosis of dyspnea in ED patients is broad, and pulmonary embolism (PE) is a crucial consideration among these. Recognition of right ventricular (RV) dysfunction is critical in patients with PE. Here, we present a 76-year-old male patient with the complaint of dyspnea. Focused cardiac ultrasonography performed by the emergency physician revealed enlarged RV, hypokinetic lateral wall and hyperkinetic apex of RV (McConnell's sign). We have screened the deep venous system of the patient with the linear probe for possible deep venous thrombosis and showed that the right dilated uncompressible popliteal vein had a thrombus formation. Computed tomography angiography of the thorax revealed filling defects in both main pulmonary arteries. Our case shows that bedside ultrasonography is a valuable tool for detecting PE and decision making in PE patients.