Diseases of the heart and arterial system : Designed to be a practical presentation of the subject for the use of students and practitioners of medicine.
- Babcock, Robert H. (Robert Hall), 1851-1930
- Date:
- 1910
Licence: Public Domain Mark
Credit: Diseases of the heart and arterial system : Designed to be a practical presentation of the subject for the use of students and practitioners of medicine. Source: Wellcome Collection.
Provider: This material has been provided by the Augustus C. Long Health Sciences Library at Columbia University and Columbia University Libraries/Information Services, through the Medical Heritage Library. The original may be consulted at the the Augustus C. Long Health Sciences Library at Columbia University and Columbia University.
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![thu pulmonic is in tlic forrespoii(liiig interspace at tlie left border of the sternnni. Jn the early years of life, by some said to be up to the thirtieth, the pulmonic second sound is the louder of the two, while at and after middle age the reverse obtains. Conditions which raise blood-i)ressure in either the lesser or greater system will correspondingly alter the intensity of these sounds. The more feeble iirst sound heard at the base at either sternal margin is probably transmitted thither from the respective ventricle. Tiegerstedt says it is not impossible that vibrations caused by the o])ening of the semilunar valves play a certain role in the production of the first heart-sound. If this be the case, then the systolic tone audible at the base of the heart in the aortic and pulmonary areas respectively, is not to be regarded merely as a conducted sound transmitted thither with less intensity than to the apex. Reduplication uf the IleaH-sounds.—Either the first or second sound may under certain conditions be doubled—that is, divided into two parts or split, as is sometimes said. This occurs most fre- quently with the second sound, and is best heard over the base of the heart. It may be iiei'ceived if the breath is held at the close of a deep ins])iration, and under these circumstances is spoken of as physiological. Falhologically such a reduplication is appar- ent when in consequence of disease there is an alteration of blood- pressure in either the pulmonic or aortic system. It is most fre- quently observed in mitral or pulmonary diseases which augment blood-pressure in the vessels of the lesser circulation. It has been contended that in such a condition the valves at the ])uhii(tnic oi'i- fice close slightly earlier than do the aortic curtains, and emit their sound an ap])r('ciable interval of time in advance. 0})})o- nents of this theory achiiit the lack of synchronism in the closure of the two sets of sigmoid valves, but maintain that the increase in blood-pressure causes a delay, not a premature occurrence of the sound, since to overcome the unnatural resistance in the pulmonary artery tlic ventricle is comix'lhMl to contract more slowly (Barr). Jn other words, the ventricle, whether right or left, de])ending on the sy.stem in which blood-jiressui'e is raised, ('om))letes its systole perceptibly latci' tlian does its fellow. (Jnttnuniirs theory of the doubling of the souiul being due to asyuclii-oiious closure of the](https://iiif.wellcomecollection.org/image/b21229533_0040.jp2/full/800%2C/0/default.jpg)
