2'7o The Symballophone 



at the apex which accompanies the systolic contraction of the ventricles. 

 Differences in time of this magnitude are readily determined by the use of the 

 symballophone in which the crossed tubes are 15 cm. longer than the direct 

 tubes, since with it differences in time of only 0.000003 sec. can be detected. 

 Furthermore, patients with aortic stenosis may present a systolic murmur at 

 the apex as well as at the base of the heart. With the symballophone it may 

 be demonstrated that the murmur appears at the apex after it has been heard 

 at the base. Apparently this murmur is propagated along the muscle of the 

 left ventricle when it is in a contracted state. With the ordinary stethoscope 

 this systolic murmur sometimes is diagnosed as a midsystolic murmur. If the 

 aortic valve is calcified and the murmur is very loud, the demonstration is easy 

 even for the novice. See figure 9. 



In patients with lesions of the pulmonary valve, congenital or acquired, 

 conditions similar to those described for the aortic valve exist. The systolic 

 murmur is not widely propagated; it is heard best in the region of the pul- 

 monary valve moving outward and upward toward the left clavicle; it is heard 

 faintly in the second right intercostal space adjacent to the sternum where 

 the right pulmonary artery passes behind the ascending aorta. This murmur 

 is not propagated beyond the larger branches of the pulmonary artery. In 

 patients who have had long-standing pulmonary stenosis, the systolic murmur 

 is prolonged, probably because the thin-walled pulmonary artery beyond the 

 obstruction is widely dilated. The time of maximum intensity appears to be 

 during or soon after the first or systolic cardiac sound. 



Two and possibly three types of congenital heart disease lend themselves 

 to analysis by means of the symballophone (fig. 9). In patent ductus arteriosus 

 (Botalli) the murmur which usually is present is heard best in the region of 

 the pulmonary artery beneath the left clavicle. Frequently it is a loud con- 

 tinuous murmur with a churning or rushing sound in the systolic phase. If 

 one chest piece of the symballophone is applied over the apex of the heart 

 and the other over the pulmonary artery, it will be readily noted that the time 

 of the systolic accentuation of the murmur is much later than the time of the 

 first apical sound. This observation indicates that the pulse wave has traveled 

 over a prolonged route which in this case is via the aorta to the ductus and 

 thence to the pulmonary artery. In my experience these conditions have been 

 met in no other clinical state. Recently, in a patient with a patent ductus 

 arteriosus (Botalli) the character of the murmur changed after the ductus was 

 tied off. The delay noted in the time of appearance of the systolic murmur 

 over the pulmonary artery could be explained by the great dilatation of this 

 thin-walled vessel after many years of strain from increased arterial pressure 

 transmitted from the aorta through the ductus arteriosus (Botalli). Theoreti- 

 cally, in a patient with patent interventricular septum the pulmonary artery 

 may become similarly dilated and thus cause a systolic murmur from relative 

 pulmonary stenosis through dilatation of the pulmonary artery after long- 

 continued hypertension in the lesser circulation. 



