Cardiac Murmurs iji 



ringing is their slamming, and thus is explained the accentuation of 

 the second sound. 



When an abnormal sound is heard over the heart, the first point is 

 to find if it is synchronous with ventricular contraction or not ; this is 

 settled by listening to the sound whilst the finger is laid on the radial 

 pulse. If the murmur be occurring with the ventricular contraction 

 it must be due either to obstruction to the outflow of blood into the 

 pulmonary artery or aorta, or to a reflux through an auriculo-ventri- 

 cular valve ; and if it be heard during diastole it must be caused by re- 

 gurgitation from the pulmonary artery or aorta, or by a difficult passage 

 from an auricle into a ventricle ; almost for certain it is due to re- 

 gurgitation, and, almost certainly, the regurgitation is from the aorta. 



The aortic and pulmonary valves slam at the same time, making 

 the second sound, which should be heard over the carotids, being pro- 

 pagated along the aorta in the blood-stream. If it cannot be heard 

 in the neck the listener concludes that the aortic valves are unable to 

 slam together, and this loss of the second sound makes him suspect 

 aortic regurgitation (p. 173). 



When the segments of the auriculo-ventricular valves do not slam 

 exactly together the first sound is spoken of as ' reduplicated. ' A 

 similar occurrence may be noticed as the lateral halves of a door- way 

 are pushed asunder ; if they swing back into the middle line at the 

 same instant a clear sound is heard, but if one of them lingers the 

 noise of the closure is blurred or reduplicated. When there is a want 

 of harmony in the closure of the aortic or pulmonary valves the second 

 sound is reduplicated. 



Cardiac murmurs. When the aortic or pulmonary orifice is 

 narrowed by chronic inflammation (endocarditis) or the presence of 

 warty excrescences (vegetations), the blood passes through it with a 

 scraping or whistling sound, called a bruit. Such bruit occurs, of 

 course, when the ventricle is contracting, and is, therefore, systolic. 

 (Systole, contraction ; o-uo-reAAa>, contract, aw with, oreAAco, send. 

 Diastole, dilatation ; 8ia, asunder, o-reAAco.) 



A river flowing peacefully in its wide bed becomes excited as it 

 approaches the artificially narrowed passage under a bridge, and rushes 

 from between its piers with an audible sound. So it is with the 

 blood-stream which traversed a valve which has been made narrow and 

 rigid by disease, and then dashes into a roomy space. The murmur 

 is probably produced just after the blood has passed through the 

 straits. In the same way, when a stethoscope is placed over and made 

 to compress the common femoral artery, the bruit does not occur in 

 the compressed part of the vessel, but in the roomy part just beyond 

 the obstruction, where the blood-stream is opening out again. 



The perfect working of a valve depends on the integrity of each 

 individual segment, and if the valve be so defective as to hinder the 

 passage of the blood its segments will probably fail completely to close 



