Physiology. — “On fibrillation of the Heart. (Part. II). On the 
Relation between Fibrillation of the Heart and “Gehüufte” 
Eetra-systoles”. By Dr. S. pr Borr. (Communicated by Prof. 
I. K. A. WeRTHEIM SALOMONSON). 
(Communicated at the meeting of March 27, 1920). 
IT 
It is remarkable that while clinicians already suspected a relation 
between fibrillation and “gehäufte” extra-systoles, both abnormal 
cardiac actions could be generated under precisely the same conditions 
in the frog’s heart. Such was the case in some of our experiments 
when at: the close of the refractory stage of the ventricle we observed 
-a series of systoles of this chamber instead of fibrillation after the 
application of an induction shock. 
This phenomenon is illustrated in the three figures which we will 
now describe : . 
In fig. 1 are shown the suspension curves and electrograms of a 
bled frog’s heart *). At 1 on the summit of the negative 7-deflection 
an induction shock is applied on the base of the ventricle. This 
evokes an extra-contraction of the ventricle, which is represented in 
the string-curve by a ventricular electrogram of which the A-deflection 
is broadened, and at the same time the magnitude of the negative 
T-deflection is increased. Previous investigations made by me went 
to show that a broadening of the R-deflection and a change of the 
T-deflection in a negative sense resulted from a slowing of the 
conduction of the excitation through the ventricle. In the experiment 
before us, the reason why after the administration of the induction 
shock the conduction of the excitation is slowed, is that the refractory 
stage of the preceding systole had come to a close a short time 
before. The metabolic condition of the ventricle was consequently 
still bad. A second result from this bad metabolic condition is the 
bad contractility of the ventricular muscle. The extra-systole 
revealing itself after the stimulus, is small (as may be read from the 
1) In every figure the electrograms were taken by placing a non-polarizable 
electrode at the apex and one on the auricles. The tension of the string was such 
that the interpolation of 1 mV. caused a deflection of the string of 1!/, mm. 
Time was registered in !/; seconds. 
