1060 Intermittent Heart Action. 



of the chest can be felt even during the pause (Fig. 184). The 

 heart beat following upon the pause is usually stronger, while 

 the subsequent beats are either normal in force, or evenly 

 weakened, or then gradually diminish in intensity. The pulse 

 behaves similarly to the heart beat (true arhythmia of Caroni 

 and Cadiot). During motion the number of heart beats is in- 

 creased, the abnormal rhythm being usually preserved, although 

 sometimes it changes in the same animal from time to time, 

 so that the pauses occur at shorter, and again at longer 

 intervals. 



Extrasystolic arh3rthmia is recognized by the rapid suc- 

 cession of two or several heart beats, which are separated from 

 the other, normal, heart beats by a pause, so that bigeminous, 

 trigeminous, etc., heart beats are noted. The pulse beat cor- 

 responding with the additional systole is usually absent; only 

 when this systole is separated from the preceding one by a 

 longer interval, or if it occurs frequently a rather feeble pulse 

 may be felt (Fig. 185). During motion the arhythmia becomes 



Fig. 185. Arhythmia of the heart due to additional systole, in a dog with cardiac 

 dilatation and inability to close the bicuspid valve, c Cun-e of heart beats. A.f. 

 Sphygmograph of the Art. femoralis, Z time in 1/5 seconds; s normal ventricular 

 systole, the pulse is distinctly felt; (s) in the sphygmograph; s' additional systole, 

 to which at + in the sphygmograph not a beat corresponds, but at s' a minimal 

 rise; s'-s" crowded additional systoles, to which in sphygmograph elevations cor- 

 respond which are in part minimal, are hardly or not at all to be felt. 



still more striking, or if it had not been observed at rest it 

 then becomes manifest. lit may often be relieved temporarily 

 by cardiotonics. 



Course. If the intermission of the heart action occurs 

 in the course of an acute disease, it disappears together with 

 its removal; but if in the meanwhile lasting changes have 

 developed in the heart, the arhythmia persists without inter- 

 fering, as a rule, with the health of the animal. In chronic 

 heart affections, however, the arhythmia disappears at most 

 for a certain time and the animals show signs of being broken- 

 winded. 



Treatment. Aside from the treatment of the basic disease, 

 animals which show a considerable degree of arhythmia should 



