This paper describes a new method for the detection of sound from within the heart in man. It employs the technic and equipment of underwater listening developed and use(l by the Navy in antisubmarine warfare. Records are shown to illustrate the localization of heart sound production to an extent not possible by phonocardiograms from the chest wall. The technic has proved helpful in the evaluation of patients with valvular and congenital heart disease.T HE purpose of this paper is to describe a new method for the detection of sounds from within the human heart. Records will be shown to illustrate that this technic enables localisation of sound production to an extent not heretofore obtainable. This investigation was supported by research grants H-1425 (C) and H-2559 from the National Heart Institute of the National Institutes of Health, U. S. Public Health Service and by a grant from the American Heart Association.Presented in part at the meeting of the American Heart Association, Cincinnati, Ohio, October 28, 1956. Abstracted, Circulation 14: 967, 1956. 764 into nonirritant plastic tubing.* Thc transduccr an(l cable were coated with silicone oil to provide lubrication for the insertion and also to provide acoustic coupling between the outer wall of the ccamv and the inner wall of the plastic tubing. The end of the catheter was then sealed chemicallv-. In the present study 2 types of catheters have been used. The first was a single-lumen catheter for sound determinations alone and was approximately a no. 5F in size. The second was a (louble-lumen catheter using the sound element of the single-lumen catheter and having the other lumen for the usual pressures and sampling. Its size was approximately that of a no. 71SF catheter. In both types, the ceramic at the tip has been made lA-inch long. The signal from the catheter was fed into a cathode follower-preamplifier unit designed specially for this study. This unit allowed the sounds to be recorded on the phonocardiographic apparatus available in our laboratory, by matching impedances and by several stages of amplification. The records were taken on the Sanborn Twin Beam photographic instrument. Tape recordings were also made with the Cambridge Educational Electron Cardioscope at a tape speed of 1.% inches per second. These were made primarily for sound speetrographic analysis by the technic described by MeKusick et al.3 and for comparison of intracardiac sounds with sounds heard on the chest wall as to duration, amplitude, and frequency. These studies will be reported in a subsequent communication.The subjects of this study, the first 41 patients on wvhom intracardiac sounds were determined, were all patients from the wards and clinics of the Philadelphia General Hospital and the heart sound studies were done in conjunction with routine cardiac catheterization. The addition of intracardiac phonocardiography to the technic of cardiac catheterization alters the latter procedlure very little. Two features of the technic of intraeardiac phonocardiography are wo...

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Three cases of atrial dissociation are illustrated with electrocardiograms. The coexisting atrial rhythms observed in published cases permit us to offer a convenient classification. Two possible explanations of this rare phenomenon are discussed.

A cylindrical barium titanate element has been placed at the distal end of a specially designed catheter and used in studies of the heart sounds of dogs and humans. Heart sounds have been recorded with the element located in the four chambers of the heart as well as in the great vessels leading from the heart. X-ray photographs monitored the location of the catheter tip in each case. The sounds have been recorded on tape and simultaneously on a photographic galvanometer recorder, all studies were continuously monitored by electrocardiogram. Sound spectrographic analysis of the several sounds was made and analyzed.

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