Pseudo-knock sound in a patient with nephrotic syndrome and massive ascites.

A patient with markedly elevated diaphragm due to massive ascites secondary to nephrotic syndrome demonstrated an intense early diastolic sound with low- and medium-pitch. This abnormal sound coincided closely with the "D" point of the anterior mitral valve echogram. This sound remarkably diminished in intensity during inspiration with lowering of diaphragm, and after removing ascites it completely disappeared. Noninvasive study with phonoechocardiograms showed neither constrictive pericarditis nor large pericardial effusion. These findings lead us to believe that the sound may be related to an abnormal ventricular recoil striking the extracardiac structures at the end of the isovolumetric relaxation time. To our knowledge, the fact that the elevated diaphragm itself can produce an early diastolic sound ("pseudo-knock sound") has not been previously reported.