This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt: ...be of material assistance if I restrict my description to the simple form and define it as a condition in which from time to time the normal ...
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1921 Excerpt: ...be of material assistance if I restrict my description to the simple form and define it as a condition in which from time to time the normal mechanism is interrupted by a series of rapid and regular beats, varying in rate between 100 and 220 per minute, the series starting and ending quite abruptly. The nature of simple paroxysmal tachycardia. It has been said that the normal pacemaker of the heart lies at the union of the superior cava and right auricle. The usual rate at which the rhythmic impulses proceed from this focus is about 72 per minute in the adult. If a new centre of impulse formation develops in any portion of the heart wall, and this centre forces responses at a rate surpassing that of the normal rhythm, then, while it is active, the new centre dominates the movements of the whole heart. Such are the paroxysms which we are about to study; they consist of sudden accelerations of heart rate in response to new-and pathological impulses. The paroxysms may be regarded In so denning it I have purposely excluded all accelerations of normal or sinus rhythm, for these are dependent upon altered innervation. I have also excluded two forms of tachycardia, which are related to that described in the present chapter; one, which is regular, but in which the auricular rate exceeds 220 per minute (see. Chapter VI); the other, which is irregular (see Chapter VII). both clinically and pathologically as formed essentially of a regular series of extrasystoles. The new impulses are elaborated in a single focus, whence the regularity of the series, and this focus lies, usually or always, at a point which is removed from the pacemaker. Fig. 34 opens with three normal heart beats, and the fourth auricular contraction (ja) is premature. Up to this point the diagram is ...
Very Good. *1912 FIRST EDITION* NICE CONDITION HARDCOVER BOOK. SMALL OWNER'S STAMP ON FRONT ENDPAPER. NO OTHER WRITING OR MARKINGS IN TEXT. ONLY LIGHT WEAR TO COVER WITH SLIGHT FRAYING AT CORNERS. A CLEAN & SOLID EARLY COPY OF AN IMPORTANT BOOK.
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