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The Diseases of the heart and of the aorta. v.1
The Diseases of the heart and of the aorta v1 Author:Thomas Hayden Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER II. PHENOMENA OF THE HEART'S ACTION IN RELATION TO THEIR MODIFICATION BY DISEASE. I Shall now briefly, discuss, individually, the cyclical series ... more »of phenomena which constitute a single action of the heart. The impulse of the heart, which, in the state of health, may be perceived by the application of the hand in the fifth intercostal space of the left side, about two inches below the level of the nipple, and one inch inside the nipple-line, is characterized by a gentle lifting motion over an irregularly circular space of about one inch in diameter. This is due to the impact of the apex and adjacent portion of the anterior surface of the left ventricle, against the chest wall; commences with the systole of the ventricles, which exceeds it in duration by one-third ; and strictly corresponds in time with the first sound. As the systole is equal to one-third of the cycle, so the impulse equals one-third of the diastole. There are at least three positive varieties of abnormal impulse, besides those of a negative character, namely: the prolonged, diffused, heaving, and double impulse of left ventricular dilated hypertrophy ; the abrupt but prolonged and heaving impulse of left ventricular simple hypertrophy ; and the abrupt hammering impulse of nervous palpitation. The impulse is liable to impairment, suppression, and displacement. It is obscured or enfeebled in fatty degeneration of the heart, and in atrophic attenuation of the left ventricular walls. In the advanced stages of the former of these conditions it may be entirely suppressed, and likewise in the worst form of typhus fever characterized by suspension of the first sound. Displacement of the apex of the heart, to whatever cause due, will involve change of the seat of impulse, and may take place in th...« less