Cardiac tamponade is a life-threatening process that must be diagnosed and treated in a timely fashion. As blood fills the pericardial sac, right ventricular filling is impeded and cardiac output is diminished, ultimately leading to cardiovascular collapse. Fortunately, emergency ultrasonography has improved the way we manage these patients today. In this report, we discuss a patient with hypotension and tachycardia who was found to have a massive loculated posterior pericardial effusion with impending cardiac tamponade. The diagnosis and appropriate treatment of this patient were rapidly ascertained with the use of bedside echocardiography. We review the literature on emergency ultrasonography, and consider the numerous instances in which emergency echocardiography can be life-saving.