A 78-year-old woman was admitted for pulmonary embolism requiring orotracheal intubation and positive end-expiratory pressure. The pulmonary angiography confirmed a massive pulmonary embolism as suggested by echocardiography. Heparin and recombinant tissue plasminogen activator were successfully administrated; nevertheless, cardiogenic shock developed. A diastolic morphology of the right-left cardiac pressures, despite a normalization of lung vasculature, was discovered by a repeated cardiac catheterization and pulmonary angiography. No tamponade was detected by echocardiography. Computed tomography demonstrated a large pneumomediastinum caused by positive end-expiration pressure, as a cause of the acute diastolic dysfunction. The patient died of a cardiac arrest after an unsuccessful drainage attempt.