CARDIAC INTKRMITTENCV IN THE HORSE. l6l 



respect of strength and rh}'thm. During the following dajs these 

 intermittencies became more frequent, one occurring after each fourth 

 or fifth pulsation. At the end of a week they could onl}' be noted after 

 a regular series of eight to ten pulsations. They did not change before 

 the animal left the hospital ; I ma}- add that digitalis had not been 

 given. 



Usually ephemeral in character, but sometimes obstinate or even 

 permanent, such intermittency is commonest in cases of pneumonia 

 which at the onset have shown other cardiac disturbance like marked 

 acceleration and violent action of the heart, or modification in the 

 sounds. 



The seriousness of intermittenc}- depends on man}- conditions, but 

 especially on its frequency, duration, and the presence or absence of 

 other cardiac troubles. When recent, and occurring during the course 

 of or during convalescence from acute diseases, it generally disappears 

 rapidly, and does not return. \\^hen of old standing (whatever the 

 primar}- disease to which it is due) it commonly indicates change in 

 the heart muscle, or in its nervous supply, and caution must be 

 observed in delivering an opinion. Though not necessarily implying 

 the existence of any organic disease, or material change in the heart, 

 yet in the great majorit}- of cases it follows injur}- to the heart muscle 

 or its nervous supply. Certain horses still continue useful for years, 

 but are none the less affected in one of their most important organs. 



The treatment resembles that of myocarditis, the principal agents 

 being the iodide of potassium or sodium and digitalis. In old-stand- 

 ing intermittency drugs have little effect ; they are onl}- useful within a 

 comparative!}- short time after the onset of disease. 



In a patient which had suffered from strangles, and in which inter- 

 mittency followed every three or four pulsations, I prescribed a zi- 

 drachm dose of iodide of potassium dail}-, afterwards increasing it to 

 3J drachms. This treatment was only commenced three months after 

 recovery from strangles, and was continued for six weeks, with two 

 interruptions of a week, the animal being meanwhile kept at quiet 

 work. At the end of two months the intermittency still continued, but 

 at longer intervals, being separated by series of six, eight, or ten pulsa- 

 tions. It afterwards became less frequent and finally disappeared. 



