Postpericardiotomy syndrome involves the development of pericardial and pleural effusion following open cardiac surgery. To date, it is not completely understood why it is more likely to develop after atrial septal defect closure. This case-based brief report describes a discrepancy in the conduit and reservoir components of atrial functions by speckle tracking echocardiography in a case following ASD closure compared to another case who had a repair of mitral cleft. This finding was associated with a mild effusion developing in ASD postoperative case. Despite the limited proofs brought by these two cases, it should encourage the implementation of larger cohort studies, testing atrial functions by STE, in patients after ASD closure, and calculating the diagnostic accuracy of different components of atrial functions in predicting PPS development.