The prognosis and optimal therapy of patients with pulmonary embolism (PE) are strongly influenced by the presence or absence of associated hemodynamic derangements. Patients with normal systemic arterial pressure have a relatively low risk of recurrent PE and death when treated promptly with therapeutic anticoagulation. Those who present with hypotension, shock, or cardiac arrest, however, have a much higher mortality rate and often receive thrombolytic therapy. Recent evidence indicates that the presence of right ventricular (RV) dysfunction identifies a subgroup of normotensive patients with a much more guarded prognosis who may benefit from more intensive therapy with thrombolytic agents. This article reviews our current understanding of the pathophysiology and diagnosis of RV dysfunction and its impact on the prognosis and therapy of normotensive patients with PE.