74 DISEASES OF THE HEART 



SLOW HEART BEAT. BRADYCARDIA. 



Definition. — The frequency of the heart beat is less than 

 normal. 



Etiology. — From a physiological standpoint it is due to a 

 stimulation of the vagus nerve from diseases of the brain 

 affecting course of vagus, or reflexly from gastro-intestinal 

 disorders. Disease of the heart (degeneration, atrophy, 

 myocarditis) may also induce it. Often the cause cannot 

 be determined. 



Symptoms. — The pulse is too slow. In the horse it may 

 be in extreme cases only 9-12-20 per minute. The force 

 of the beat is normal and the condition of the patient good. 



Diagnosis. — To determine whether bradycardia is due to 

 an irritated vagus or to some lesion of the heart itself, 

 sulphate of atropin (gr. J) may be injected subcutaneously. 

 If from the vagus it will temporarily disappear after giving 

 the atropin. 



Treatment. — Excitants (alcohol, ether, atropin) may be 

 tried if the condition produces symptoms of heart weakness, 

 languor, stupor, or nervous symptoms (convulsions). 



INTERMITTENT HEART BEAT. 



Arhythmia Cordis. 



Definition. — A condition in which one or more heart beats 

 are omitted. 



Etiology. — An intermittency of the heart is quite common 

 in horses. It may exist for some weeks and disappear 

 spontaneously. On exercise the symptom may temporarily 

 disappear. Common causes are: (a) Brain diseases affect- 

 ing the vagus (hydrocephalus, tumor, cerebritis) ; (6) digestive 

 disorders (constipation, catarrh); (c) diseases of the heart 

 itself (myocarditis, endocarditis). 



- Symptoms. — One or more heart beats are dropped. It 

 may be every fourth, sixth or eighth beat and occur with 

 great regularity. Usually the beat following the pause is 

 louder than the others. It may happen that two beats 



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