We report the case of a 41-year-old woman admitted to the hospital due to cardiac tamponade as the first manifestation of a pulmonary neoplasm. The patient developed an early biventricular dysfunction and pulmonary edema after removal of the pericardial effusion, with complete recovery within ten days. Since transient ventricular dysfunction after pericardiocentesis is a very unusual complication, we present a review of the different mechanisms suggested in the literature to explain the pathophysiology of this rare phenomenon.