“…It occurs in association with congenital pericardial defects and traumatic disruption of the pericardial sac. 1 It is also seen as a complication of pulmonary surgery, especially intrapericardic pneumonectomy without closure of pericardial defect, 2,3 or lobar resection with pericardial opening. 4,5 It appears to be related to negative intrapleural pressure, positive-pressure breathing, or changes in the position of the patient.…”