Right ventricular dysfunction is an important component of the pathophysiology of several disorders commonly encountered in the emergency department (ED). Interventions often performed routinely early in the ED course such as fluid administration and endotracheal intubation have the potential to cause precipitous clinical deterioration in patients with right ventricular failure and pulmonary hypertension. It is important for emergency physicians to understand the pathophysiology of acute decompensated right ventricular failure in order to avoid common pitfalls in diagnosis and management that can result in significant morbidity and mortality.