Intracardiac Phonocardiography in Man

Abstract

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...

Intracardiac phonocardiography: intracardiac sound and pressure in man.

“…Lewis et al 3 recorded heart sounds and murmurs in the lesser circulation with a barium titanate transducer and noted the technique was capable of localizing heart sounds and murmurs to an extent not previously possible. The frequency response of the catheter preamplifier system was linear over the range of heart sounds; however, since the response of the barium titanate dropped off sharply below 10 Hz it was not possible to record simultaneous intracardiac pressures.…”

Variability in the Detection of a Fourth Heart Sound -Its Clinical Significance in Elderly

“…The recordings were analyzed by a fourth and fifth physician independently of each other. The S4 was identified as a low frequency transient (20-70 cps) which is usually composed of one or two vibrations during late diastole [6,9,10,16,17]. The first component, thought to be associated with atrial contraction per se, is made of low frequency vibrations and is inaudible.…”

Intracardiac Phonocardiography in the Diagnosis of Small Patent Ductus Arteriosus With Atypical Murmur

“…Even with normal pressures in the pulmonary artery the murmur may be atypical (5), and the only auscultatory sign may be an isolated systolic murmur if the ductus is rather small (3).…”