Dear Editor, A 52-year-old female patient with a history of hypertension and a recently performed right knee arthroscopy consulted to our emergency department with severe shortness of breath, tachycardia, tachypnea, and oxygen saturation of 80%. Ten minutes after admission, the patient suffered cardiac arrest with pulseless electrical activity (PEA). Cardiopulmonary resuscitation was initiated immediately, and a heart ultrasound was performed. Right dilated ventricle, interventricular septum flattening, and paradoxical movement were evidenced. Accordingly, the attending physician decided to start thrombolytic therapy (alteplase 50 mg bolus). After 5 min, the patient returned to spontaneous circulation and care was continued in the Intensive Care Unit. Two weeks later, she was discharged from the hospital without any sequela. Pulmonary embolism (PE) is a cause of cardiac arrest presenting with PEA. In fact, 36% of patients who experience cardiac arrest and PEA have PE.[1] Massive PE (MPE) leads to sustained hypotension, pulselessness, or persistent profound bradycardia. Its mortality reaches 65%.[2] Echocardiographic diagnosis of MPE is based on signs of the right ventricular overload. Although echocardiography is operator-dependent, it can guide decision making in the acute setting.[3] Some ultrasonographic signs of MPE are interventricular septum flattening and paradoxical movement, McConnell's sign, and 60/60 sign [Figure 1].[4] Interventricular septum flattening and paradoxical movement have a sensitivity and specificity of 81 and 45%, respectively.[4] McConnell's sign has a sensitivity and specificity of 70 and 33%, respectively. The 60/60 sign has a sensitivity of 19 and a specificity of 94%.[5] Low-diagnostic accuracy for each individual echocardiographic sign warrants their combined use to achieve a greater diagnostic certainty.Figure 1: (a) Parasternal long axis view showing dilated right ventricle, hypokinetic wall of the right ventricle and the interventricular septum, (b) parasternal short axis view showing a flattened interventricular septum, with paradoxical movement and a “D” shaped left ventricle (SonoSite Edge, SonoSite, Inc. 21919 30th Drive SE Bothwell W. A.)Financial support and sponsorship The financial support was provided by Fundación Valle del Lili. Conflicts of interest There are no conflicts of interest. Acknowledgement We would like to acknowledge Watts, Freddy A., M.D. Doctor in charge of the initial management of the patient.