PHONOCARDIOGRAPHY 729 



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OUTFLOW 

 TRACT 



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FIG. 12. Intracardiac phonocardiogram, illustrating another aspect of acoustic localization. These 

 recordings were taken from a 7-year-old boy with a \entricular septal defect with a left-to-right 

 shunt. The upper recording shows the intracardiac phonocardiogram taken from the outflow tract 

 of the right ventricle and shows a loud regurgitant-type systolic murmur. The lower recording taken 

 from the midportion of the right ventricle (note the premature ventricular contractions) shows 

 little or none of the murmur heard in the outflow tract. 



fA)PULMONIC AREA.CHEST 



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FIG. 13. Intracardiac phonocardiogram, illustrating the use of this technique in investigating the 

 transmission of acoustic events to the chest wall. These recordings were taken from a 3-month-old 

 boy with a patent ductus arteriosus with a left-to-right shunt and with pulmonary hypertension. 

 The pulmonary artery pressure was equal to the pressure in the aorta. The .4 recording shows 

 the phonocardiogram at the time of cardiac catheterization recorded at the pulmonic area on the 

 chest (upper left sternal border). Note that here there is a systolic murmur, a loud second sound, 

 but no diastolic murmur. In contradistinction to this, the recording taken from within the pulmonary 

 artery (record B) shows both systolic and diastolic components, in reality a continuous murmur. 

 The recording C from within the right ventricle shows no murmur. 



communication as being in the lesser circulation. A 

 decrease with inspiration or an increase with expira- 

 tion identifies the murmur as either wholly originating 

 on the systemic side or from a left-to-risjht shunt. 



INTR.\CARDI.\C PHONOCARDIGGR.^PHY 



In the investigation of the physiological correlates 

 of cardiac acoustics one powerful tool that has 



recently been introduced is the intracardiac phono- 

 cardiogram. This method utilizes the technique of 

 cardiac catheterization to record the events from 

 within the heart and circulation. The proper applica- 

 tion of all of the various types of catheterization, i.e., 

 sites of entry of the catheter, allows for introduction 

 of the transducer into all chambers of the heart and 

 virtually all major vessels. Various transducers have 

 been applied, all with the aim of recording the 

 vibrations in the audible frequency range. 



