Part I--Phonocatheters: Their Design and Application

A miniature cylindrical barium titanate tubular element has been designed as an acoustic pickup and placed at the distal end of a specially designed catheter. The catheter is, in fact, an extension of the general design technique used to evolve underwater sound transducers used in antisubmarine warfare. Catheters have been designed in both single and double-lumen types, with provisions in the latter case for the usual practice of heart catheterization simultaneously with the phono work. Details of the response of the catheters and performance of the experimental system used are given. Sound spectrograms which plot time as the abscissa, frequency as the ordinate, and amplitude as the density have been made, as well as conventional photographic recording galvanometer records. Preliminary experimentation was carried out in dogs where both left and right catheterizations are cited.