90 



Scientific Proceedings (118). 



lar activity, were well formed, even in the first normal beats, 

 though showing some tendency to slight alterations both in form 

 and in voltage during the early cycles of the restored sequential 

 mechanism. 



On the day on which normal rhythm was established the rate 

 usually fell to 80 or 90, and on the following day to 60 or 70, and 

 subsequently remained at or about this level. During the time 

 the normal rhythm prevailed, it was common to see occasional 

 auricular premature beats. These, together with ventricular pre- 

 mature contractions, when these were present, could be abolished 

 by giving more of the drug. 



P-R (conduction) time, after appearance of the sinus rhythm, 

 was within normal limits in two patients, and was lengthened 

 appreciably in the third. It is not possible to say whether the 

 drug was responsible for delaying conduction of the impulse 

 through the auriculo-ventricular bundle in this instance. 



In one patient the QRS interval, which may be taken to 

 indicate the time of the conduction of the impulse through the 

 ventricles, was lengthened. In two patients, after establishment 

 of normal rhythm, there was alteration in the form of the ven- 

 tricular complex, exhibiting itself commonly as a change in the 

 voltage and contour of the R and S waves. 



The T wave often tended to reverse its direction and change 

 its voltage after the normal rhythm was restored, returning to its 

 original direction and form after reversion to the fibrillatory 

 mechanism. 



In one patient paroxysms of ectopic ventricular tachycardia 

 preceded the onset of impure flutter, which, in turn, was followed 

 by the normal rhythm. In this same patient sino-auricular block 

 and paroxysms of auricular tachycardia were also observed when 

 the sequential rhythm prevailed. 



Digitalization prior to quinidinization was not an essential 

 factor for success in therapy, for in the same individual the normal 

 mechanism was restored on one occasion with ventricular rate of 

 180 and at another time, after the administration of digitalis, 

 when the ventricular rate ranged from 90 to 100. 



The duration of the normal rhythm after a single course of 

 quinidine varied from a few hours to 23 days. In one patient it 



