Pericardial window: mechanisms of efficacy.

Although the term implies a persistent communication through which fluid might drain, how a pericardial window works is not clear. We believe that the mechanism of success is not window but rather fusion of the epicardium to the pericardium with obliteration of the potential space. To evaluate this, we studied 28 patients, all of whom underwent a subxiphoid pericardial window procedure with tube drainage maintained until output was minimal. There were no operative deaths, and 26 patients (92.9%) obtained permanent relief. Postoperative echocardiograms demonstrated thickening of the pericardium/epicardium and obliteration of the pericardial space. Autopsy performed on 4 patients who died of their underlying malignancy confirmed this fusion, which begins as an inflammatory process. A subxiphoid pericardial window relieves effusions with a low operative mortality and good long-term success (92.9%, 26 of 28). This success is dependent on the inflammatory fusion of the epicardium to pericardium and not maintenance of a window. Tube decompression should be maintained until fluid output is minimal to allow apposition and fusion of the two surfaces.