HighlightsPericardial Decompression Syndrome is an unexpected clinical scenario with an incidence less than 5% in all surgically or percutaneously managed pericardial tamponade patients.Yet, in the majority of cases there is no obvious cause for the development of paradoxical ventricular dysfunction after decompression.Close postoperative monitoring for the first 24 h, preferably in the ICU, and aggressive heart failure treatments should be managed even if low cardiac output develops.We recommend gradual removal of pericardial effusion under hemodynamic monitoring, especially in patient with postcardiotomy tamponade.