VOLUNTARY REGULATION OF THE HEART BEAT

1918 Journal of the American Medical Association (JAMA)  
The frequency of the heart beat, which expresses itself in the pulse rate, is one of the various vital phenomena over which conscious control is not ordinarily exercised. There may be marked differences in the pulse rate found in different individuals without their having any pathologic significance attached to them, although the newer studies in nutrition, notably those of F. G. Benedict at the Boston Nutrition Laboratory of the Carnegie Institution of Washington, have tended to show a
more » ... d to show a surprising parallelism between pulse rate and the intensity of metabolism. It is well known that the heart beat is quickened by warmth and diminished by cold applied to the surface of the skin of the vagus. The act of swallowing causes a reflex increase in heart rate by inhibition of the tonic action. The function of the nervous system in the control of the frequency of the heart beat is familiar to every student of medicine. He has seen the inhibitory effect of vagus stimulation, the abolition of the tonic influ¬ ence of the vagus by injury to the nerve or destruction of its center, and the augmentor effect of stimulation of the accelerators of the heart. Such demonstrations are experimentally produced effects. There are, how¬ ever, published records of thirteen persons who pos¬ sessed the power to accelerate their heart beat at will, the earliest authentic account dating back to 1872.1 The newest case, in the person of a skilled observer,2 has been carefully studied with a view to ascertaining the nature of the mechanism of acceleration. The uncertainty regarding this has wavered between the possibility of a removal of vagai influences, second after the command is given by the observer. The acceleration does not reach its maximum at once, several beats occurring before the high mark is attained. The degree of acceleration is greater, the stronger the impulse and the fresher the condition of the subject. The greatest acceleration recalled was an instance in which the pulse rate rose from 104 to 200, this paroxysm lasting for thirty seconds. According to the subject, it seems impossible to describe the sen¬ sations attending the production of the acceleration any more than one can describe the conscious effort in voluntary movement of the arm. With the onset of the tachycardia there is a feeling of "fulness" or ting¬ ling over the whole body. A mild exhilaration follows in a few seconds, and moderate fatigue results if the paroxysm is induced several times successively, or for any period longer than a very few seconds. The acceleration is dependent on a distinct effort of the will, and the strain is as tiring as that produced by holding up a heavy weight ; it is not a succession of efforts, but one that is continuous. Distinct relief is felt with the cessation of the acceleration. The physiologic investigation of this subject showed that with the onset of the acceleration there is no apparent change in the situation of the "pacemaker"that collection of peculiar muscular tissue in intimate relation to the nerves entering the heart, and from which the normal beat is now believed to arise. The changes in the electrocardiographic deflections during the acceleration are those that are known to occur when the sympathetic nerves are stimulated experi¬ mentally. The ability to accelerate the rate of the heart beats persists after the suppression of vagus action by atropin. The evidence available suggests that the voluntary increase of the heart rate is the result, in great part at least, of the action of the accel¬ erator nerve mechanism, and that it is not due solely or chiefly to the withdrawal of vagai action. MEDICAL PRACTICES IN SOME PHILIP-PINE PROVINCES The history of medicine shows that at practically all stages of civilization, and among the most diverse types of races, man gradually learned by experience to appreciate the effects of certain agencies for good or harm in relation to his own person. In his story of the growth of medicine from its earliest period, Buck1 has portrayed how the powers of observation and the reasoning faculty presumably have been applied to the avoidance of bodily dangers and the relief from physical suffering. Buck suggests how man "gradually learned that cold, under certain circumstances, is competent to produce pain in the chest, shortness of breath, active secretion of mucus, etc., and his instinct led him, when he became affected in this manner, to
doi:10.1001/jama.1918.02600190030010 fatcat:vrg7i4vsyrek3ginrlc4npxemy