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

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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$aniiiiation of a patient \vc therefore avail ourselves of the knowl- edge that forcible cardiac action intensiiies a luurniur l)v having him jnnip about or otherwise excite his heart to bring out an otherwise faint or inaudible murmur. Posture also influences the loudness of these sounds, some being more plainly, others less distinctly, heard in the recumbent position. Those of stenosis are more intense in the erect posture, while those of regurgitation are so in the recumbent. The reasons for such variations in intensity are based on the influence of the force of gravity, which is greater in some than in other positions (Gibson). Mitral systolic murmurs are nevertheless often louder in the upright than the supine posture, an effect to be attributed to the greater vigour of ventricular contraction when the patient stands. There are so many exceptions to the effect ordinarily exerted by position that a patient should always be examined sitting, standing, and reclining. The pitch depends upon the rapidity of the vibrations pro- ducing the murmur. Therefore, some murmurs are low-])itched, while others are high. The union of overtones with the funda- mental tone determines quality, and as pitch and quality go hand in hand, low-pitched murmurs are apt to be rumbling, growling, rasping, etc., while shrill ones are often musical, whistling, filing, sawing, twanging, and the like. Finally, the duration of murmurs is variable, depending on the length of time the vibrations endure. Other things being equal, it requires more time for the blood-stream to pass through a nar- rowed orifice than it does for it to regurgitate tlirough wider os- tium whose valve is defective, and therefore direct murmurs, as those of stenosis are called, are generally of greater duration than are the indirect ones of valvular insufiiciency. Tt may be stated as a general proposition, therefore, that the murmurs of ob- struction are less intense, lower in pitch, less musical in (juality, and of longer duration than are those of regurgitation, which, for the sake of emphasis, may be conversely stated to be higher, louder, more musical, and shorter. There are, however, excep- tions to this law. Fortunately, murmurs generated synchronously yet at different ostia are never identical in these four character- istics, and hence are usually distinguishable fi-oui ciK-h other. It is also of the utmost importance to note the rhythra of mur-$