The Point of Maximum Intensity of Aortic Diastolic Regurgitant Murmur

With Special Reference to the "Right-Sided" Aortic Diastolic Murmur

Abstract

The point of maximum intensity (PMI) of the aortic diastolic murmur was analyzed in 801 cases of aortic insufficiency (AI) of various etiology, and unusual location including the "right-sided" murmur was investigated.
Though the PMI was widely distributed, a great majority of cases had the PMI along the left sternal border irrespective of the etiology concerned. Particularly, the 3rd and the 4th left sternal border (3L and 4L) were the main places where the murmur was best audible and this was observed in 598 out of 801 cases (74.5%). Mid-sternal portion (3M) was the secondary place and 99 cases (12.5%) had the PMI here.
Rather infrequent PMI was along the right sternal border (58 cases ; 7.1%) and around the cardiac apex (21 cases ; 2.5%). The other PMI was exceptional.
The "right-sided" AI murmur was observed predominantly in syphilitic case (27 out of 58 cases ; 47%). However, almost all of the other etiological entity could have the PMI along the right sternal border even in a few cases of rheumatic etiology. Moreover, the syphilitic cases did not always have the PMI along the right sternal border, and it was located on the left side in about a half of cases.
The "right-sided" AI murmur was usually loud enough to permit the wide transmission of the murmur over the precordium. The PMI was located more frequently in the classical aortic area (the 2nd right sternal border ; 2R: 36 cases ; 61%) rather than in the 3rd right sternal border (3R: 18 cases ; 28%), and it was located even in the 1st right sternal border (1R: one case). The cases with the PMI in the upper right sternal border (1R and 2R) usually had louder murmur in 3R than in 3L, but the exception was observed in some cases (4 cases ; 11%). Therefore, the concept of the "right-sided" AI murmur was revised to include all of the cases which have the PMI along the right sternal border irrespective of the interspaces questioned.
Roentgenograms revealed the dilatation of the ascending aorta and the rightward displacement of the aortic root in all cases with the "right-sided" murmur. However, in cases with the PMI in 2R the elongation of the aorta predominated, whereas the rightward displacement of the aortic root was dominantly observed in cases with the PMI in 3R. The height of the diaphragm was the one of the accessory factors influencing the site of the PMI. In addition, all cases with the "right-sided" murmur had marked left ventricular enlargement, which also contributed to the rightward shift of the PMI. The conclusion was made that these roent-genographic abnormalities have the primary importance to the "right-sided" murmur rather than the etiology concerned.
Because of the lack of the exact auscultatory and phonocardiographic description, aortic insufficiency associated with aortitis syndrome in the Orient was analyzed and discussed in detail.