Disturbances of the Heart | Page 4

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DISTURBANCES OF THE HEART
Discussion of the Treatment of the Heart in Its Various Disorders, With
a Chapter on Blood Pressure

OLIVER T. OSBORNE, A.M., M.D. Professor of Therapeutics and
formerly Professor of Clinical Medicine in Yale Medical School NEW
HAVEN, CONN.

THE JOURNAL of AMERICAN MEDICAL ASSOCIATION Five
Hundred Thirty-Five North Dearborn Street, Chicago

PREFACE

The second edition of this book is offered with the hope that it will be
as favorably received as was the former edition, The text has been
carefully revised, in a few parts deleted, and extensively elaborated to
bring the book up to the present knowledge concerning the scientific
therapy of heart disturbances. A complete section has been added on
blood pressure.

PREFACE TO THE FIRST EDITION
That marvelous organ which, moment by moment and year by year,
keeps consistently sending the blood on its path through the
arteriovenous system is naturally one whose structure and function
need to be carefully studied if one is to guard it when threatened by
disease. This series of articles deals with heart therapy, not discussing
the heart structurally and anatomically, but taking up in detail the
various forms of the disturbances which may affect the heart. The
cordial reception given by the readers of The Journal to this series of
articles has warranted its issue in book form so that it may be slipped
into the pocket for review at appropriate times, or kept on the desk for
convenient reference.

CONTENTS
Preface Preface to First Edition Disturbances of the Heart in General
Classification of Cardiac Disturbances Blood Pressure Hypertension
Hypotension Pericarditis Myocardial Disturbances Endocarditis
Chronic Diseases of the Valves Acute Cardiac Symptoms: Acute Heart
Attack Diet and Baths in Heart Disease Heart Disease in Children and
During Pregnancy Degenerations Cardiovascular Renal Disease
Disturbances of the Heart Rate Toxic Disturbances and Heart Rate
Miscellaneous Disturbances

DISTURBANCES OF THE HEART IN GENERAL

Of prime importance in the treatment of diseases of the heart is a
determination of the exact, or at least approximately exact, condition of
its structures and a determination of its ability to work.
This is not the place to describe its anatomy or its nervous mechanism
or the newer instruments of precision in estimating the heart function,
but they may be briefly itemized. It has now been known for some time
that the primary stimulus of cardiac contraction generally occurs at the
upper part of the right auricle, near its junction with the superior vena
cava, and that this region may be the "timer" of the heart.
This is called the sinus node, or the sino-auricular node, and consists of
a small bundle of fibers resembling muscle tissue. Lewis [Footnote:
Lewis: Lecture in the Harvey Society, New York Academy of
Medicine, Oct. 31, 1914.] describes this bundle as from 2 to 3 cm. in
length, its upper end being continuous with the muscle fibers of the
wall of the superior vena cava. Its lower end is continuous with the
muscle fibers of the right auricle. From this node "the excitation wave
is conducted radially along the muscular strands at a uniform rate of
about a thousand millimeters per second to all portions of the auricular
musculature."
Though a wonderfully tireless mechanism, this region may fall out of
adjustment, and the stimuli proceeding from it may not be normal or
act normally. It has been shown recently not only that there must be
perfection of muscle, nerve and heart circulation but also that the
various elements in solution in the blood must be in perfect amounts
and relationship to each other for the heart stimulation to be normal. It
has also been shown that if for any reason this region of the right
auricle is disturbed, a stimulus or impulse might come from some other
part of the auricle, or even from the ventricle, or from some point
between them. Such stimulations may constitute auricular, ventricular
or auriculoventricular extra contractions or extrasystoles, as they are
termed. In the last few years it has been discovered that the
auriculoventricular handle, or "bundle of His," has a necessary function
of conductivity of auricular impulse to ventricular contraction. A
temporary disturbance of this conductivity will cause a heart block, an

intermittent disturbance will cause intermittent heart block
(Stokes-Adams disease), and a prolonged disturbance, death. It has also
been shown that extrasystoles, meaning irregular heart action, may be
caused by impulses originating at the apex, at the base or at some point
in the right ventricle.
In the ventricles, Lewis states, the Purkinje fibers act as the conducting
agent, stimuli being conducted to all portions of the endocardium
simultaneously at a rate of from 2,000 to 1,000 mm. per second. The
ventricular muscle also aids in the conduction of the stimuli, but at