Sound spectrographic diagnosis of aortic ball variance.

Abnormalities in the silastic poppets of cardiac valve prostheses have been detected with increasing frequency. Ball variance can cause serious mechanical dysfunction of the prosthesis and can result in sudden death. Contour sound spectrograms were recorded on 12 patients with ball variance confirmed by operation and 25 controls. In ball variance the frequency of the aortic opening sound at the second right intercostal space was decreased, with the peak frequency recorded being below 1,300 cycles/sec in 11 of the 12 patients. The peak frequency was greater than 1,300 cycles/sec in 24 of the 25 control patients. The remaining patient had peak frequencies in both the normal and abnormal range. The diagnosis of aortic ball variance in patients with triple valve replacement remains difficult because of the nearly synchronous tricuspid closing and aortic opening sounds. The sound spectrographic findings have been the most reliable objective evidence of ball variance in patients with Starr-Edwards aortic prostheses of the Model 1000 series.