BRADYCARDIA AND ARRHYTHMIA Retardation of the heart action in childhood is almost always associated with irregularity of the pulse. Only this retardation of the pulse with arrhythmia in childhood is not always so marked, because of the higher pulse rate. Therefore periodic arrhythmia (double pulse) which is always caused by organic heart disease in adults, is hardly to be considered in children; much more frequently simple irregularity and inequality of the pulse are noted.
Physiologic arrhythmia, without retardation of the pulse, is an expression of the physiologic nervousness of children (Weill) which can be plainly observed, especially during sleep; but it may also occur front excitement, tlae irritation of cold or heat, or after unusual bodily exertion.
Arrhythmia is very rare ita the heart affections of childhood, except in the diphtheritic heart, with which there is always high-grade, brady cardia; and is more frequent in myocarditis and pericarditis than in endocarditis and valvular lesions.
More important is the arrhythinia accompanied by retardation of the pulse seen in the course of endogenous and exogenous poisons. All heart poisons may lead to this pulse disturbance, belladonna, digitalis, caffeine, opium, chloroform. Certain gastro-intestinal autointoxications, associated with constipation and acetomemia, and jaundice may produce bradycardia and arrhythmia in children, while jaundice often causes an astonishingly low pulse-rate, 56 to 60 a minute.
In the acute infectious diseases it is not (luring the period of fever, but after the fever has fallen and during convalescence, that arrhythmia appears. As a rule, arrhythmia and bradycardia occur together, in the course of an infectious disease, at the lowest point in the temperature curve, sometimes simulating a. mening,itic symptom-complex. The often high-grade bradycardia in ffiphtheria, in which the arrhythmia as a rule is less noticeable, depends upon toxic diseases of the heart muscle, as has already been mentioned.
Paroxysmal bradycardia, in a child 4 years of age, with a pulse of from 35 to 8(1, following inflannnatory rheumatism and accompanying myocarditis, desctibed by Schuster, is to be regarded as an unique obser vation.
Bradycardia and arrhythmia are often found associated in the course of organic diseases of the central nervous system. Tuberculous meningitis in children gives the lowest pulse-rate.
Simple arrhythmia, without bradycarclia, is as a rule, found in chorea, in amen-lie, nervous children, and in those suffering from intes tinal worms. Arrhythmia is also frequently found with appendicitis in children and in acute intestinal affections with great loss of fluid. At tacks of migraine in school children are often accompanied by arrhy thmia also, with constant, though slight retardation of the pulse.
Bradycardia, like tachycardia, can be produced by compression of the vagus with hyperplasia of the bronchial glands (von Starck), when the Stokes-Adams symptom-complex may appear, continued slow pulse with epileptiform and syncopal attacks (Charcot).
Pulsus paradoxus, described by Kussmaul, is not to be confounded with arrhythmia. Occurring with weakening of the radial pulse during inspiration, it is found in children with callous mediastino-pericarditis, with large mediastinal tumors, with the inspiratory spasm of laryngismus stridulus and in diphtheria (Varlet).
While simple arrhythmia, associated with slight retardation of the pulse, is usually an ephemeral condition of little cliagnostic importance in childhood, when it is accompanied by true bradyeardia, it is almost always of longer duration and dependent upon deeper causes, such as severe disturbance in the action of the heart muscle, deeper changes in the nervous mechanism of the heart or organic changes in the central nervous system.
The treatment depends upon the nature of the fundamental disease.