A system of practical medicine. By American authors. Vol. 3

by Unknown

Palpation.—The impulse is felt to be forcible, and is sometimes accompanied by a heaving or lifting motion. The apex is displaced toward the left and slightly downward. A sensation will sometimes be imparted to the hand during systole similar to that produced on the sense of hearing by the whizzing of a missile by the ear. This is often nothing more than an intensified endocardial thrill. This systolic frémissement radiates to the ensiform process of the sternum, being most intense in the second right intercostal space.

Percussion.—The area of cardiac dulness will be increased in proportion to the displacement of the apex-beat to the left. The increase in dulness measures the amount of left ventricular hypertrophy.

Auscultation.—Aortic stenosis produces a systolic murmur which more frequently accompanies than replaces the first sound of the heart. The maximum intensity of this murmur is usually at the second sterno-costal articulation of the right side, but it may be heard with equal intensity over the whole upper part of the sternum, and followed up the aorta and along the carotids; again, it may be loudest at the xiphoid cartilage, or it may be heard with greatest intensity at the junction of the left third rib with the sternum. In most cases the first sound is heard with the murmur, but the murmur may entirely replace or obscure it. This murmur is usually loud and harsh in character, and is loudest at the beginning of the systole. Harshness is one of its distinguishing characteristics.

In pure aortic stenosis the aortic second sound may be inaudible, and is always feeble, but the pulmonic second sound will always be audible. The area of diffusion of this murmur follows the law that a murmur is propagated in the direction of the blood-current. It is conveyed along the aorta into the carotids, and one of its characteristics is that it is heard in the great vessels of the neck. It may sometimes be heard in the thoracic and abdominal aorta.

When an aortic obstructive murmur is heard at the apex its intensity is diminished, and when heard behind it is most distinct at the left of the third and fourth vertebræ near their spines, and frequently extends downward along the spine in the course of the aorta, but with diminished intensity. It is to be noted here that a systolic murmur, audible at the base, and traceable along the ascending arch toward the end of the right clavicle, is by no means limited to cases of aortic stenosis, although aortic stenosis always produces a murmur with these characteristics.

Arterial murmurs, synchronous with the cardiac systole, are far more frequent than diastolic murmurs. When the mitral or tricuspid valves are thickened or incompetent, or when the myocardium is the seat of extensive fatty degeneration, the murmur of aortic obstruction will entirely replace the first sound of the heart.

DIFFERENTIAL DIAGNOSIS.—Aortic obstruction may be mistaken for mitral regurgitation, tricuspid regurgitation; an anæmic bruit, for the murmur of a thoracic aneurism and for a murmur produced by a scabrous condition of the ascending arch of the aorta.

1. Both mitral and tricuspid regurgitation, as well as aortic stenosis, are recognized by a systolic murmur. The murmur of aortic obstruction is heard with its maximum intensity at the second right sterno-costal articulation, and diminishes in intensity toward the apex. The murmur of mitral regurgitation is heard with greatest intensity at the apex-beat. The murmur of aortic obstruction is conveyed into the vessels of the neck; that of mitral regurgitation to the left, in the direction of the apex-beat, and is heard behind, between the fifth and eighth dorsal vertebræ, at the left of the spine, with very nearly the same intensity as at the apex. The pulse in aortic stenosis is hard, firm, and wiry in character, but regular, while in mitral regurgitation the pulse is irregular in rhythm as well as in force, is never incompressible, and is easily increased in frequency. Gastric, intestinal, renal, hepatic, and bronchial symptoms are present in mitral regurgitation, while the subjective symptoms of aortic obstruction are cerebral in character. The pulmonic second sound is generally feeble in aortic stenosis, while in mitral regurgitation it is intensified. The murmur of aortic stenosis is harsh; the murmur of mitral regurgitation is soft, and frequently musical in character.

2. Tricuspid regurgitation is also accompanied by a systolic murmur. But while the murmur of aortic stenosis has its maximum intensity at the right second sterno-costal articulation, the murmur of tricuspid regurgitation is very rarely heard above the third rib: this is an important diagnostic sign. Tricuspid regurgitation is accompanied by jugular pulsation, while the murmur of aortic obstruction is heard in the arterial trunks of the neck. To distinguish between intrinsic pulsation of the jugular vein and throbbing of the carotid arteries press lightly on the vessel above the clavicle; this arrests pulsation when due to tricuspid disease, while if due to aortic stenosis the result is negative. Moreover, respiration influences jugular pulsation, while it has no influence over carotid throbbing. The area of transmission of tricuspid regurgitant murmurs is not more than two inches from the point of their maximum intensity; whereas the aortic obstructive murmurs are conveyed along the sternum into the vessels of the neck. There is nothing peculiar or abnormal about the pulse of tricuspid regurgitation, while the hard and wiry pulse of aortic obstruction is quite characteristic.

3. An anæmic bruit may be mistaken for aortic stenosis, since the rhythm and seat of the bruit are often identical with those of the stenosis. Anæmia, however, produces a murmur that is heard loudest in the carotids, and is accompanied by a venous hum, the bruit du diable, which is continuous, and heard best on the right side of the neck. Thus in anæmia there are three murmurs, arterial, cardiac, and venous. In aortic disease the murmur has its maximum intensity at the second sterno-costal articulation of the right side, and is not accompanied by a venous hum. There is always more or less cardiac hypertrophy in stenosis, and an increase in the force of the apex-beat, while anæmia is attended by a feeble cardiac impulse. The murmur is soft and blowing in anæmia and harsh and rasping in aortic obstruction. The pulse is characteristic in aortic stenosis; in anæmia it may have a thrill, but is never hard and wiry. Lastly, the subjective signs of anæmia will render the diagnosis comparatively easy, especially when the hum in the veins coexists.