79 



incompatible with their normal characters; cessation of 

 these excitatory impulses is speedily followed by a reversion 

 to the more moderate rates that are compatible with the 

 normal type of beat. The non-persistence of the abnormal 

 condition is due to the fact that the mechanism of circu- 

 lating excitation, characteristic of true fibrillation, has 

 not been fully established. To this condition 1 have applied 

 the term " pseudo-fibrillation." It is probable that most, if 

 not all, the alleged instances of transient fibrillation in man 

 where recovery occurred — apart from the application of 

 cardiac massage — were examples of pseudo-fibrillation as 

 recognized experimentally; this would account for the 

 features observed in man during the brief attack, and for 

 the subsequent recovery. 



Such is probably the explanation of such a case as that 

 described by llobinson and Bredeck^^ in which there were 

 repeated syncopal attacks simulating those of the Adams- 

 Stokes syndrome; in one of these attacks an electro- 

 cardiographic record was obtained and showed characters 

 apparently resembling in some measure those of ventricular 

 fibrillation — followed by recovery. In another case F. M. 

 Smith'^ obtained an electrical record suggestive of fibrilla- 

 tion, the attack being recovered from within a minute. 

 Hoft'mann^* has also published an electrical curve of a 

 temporary condition evidently approximating to, but not 

 reaching, the fully developed condition of fibrillation. There 

 is also a case reported by Kerr and Bender^ ^ of temporary 

 fibrillation or a closely allied condition (under quinidine 

 therapy) where records were obtained. 



The Question of Becovery from True Fibrillation. 



As has been already stated, spontaneous recovery from 

 ventricular fibrillation is very frequently seen in the hearts 

 of the lower mammals — for example, rat — but recovery is 

 increasingly difficult and rare in the higher forms. In the 

 cat and rabbit, after true fibrillation has lasted for periods 

 of considerable duration (minutes), the ventricles may, 

 without treatment, sometimes show cessation of the fibrilla- 

 tion movement and " spontaneous " recovery of the power 

 to execute weak co-ordinated beats, with more or less definite 

 pumping out of blood from their chambers into the arteries. 

 This recovery occurs too late as a rule, if not invariably, to 

 provide for continuance of the life of the animal, for the 

 collapse of the circulation has lasted too long for restoration 

 of the vital functions. Most instances of true fibrillation do 

 not show this sort of ventricular " recovery "; the fibrilla- 

 tion movement usually becomes slower and feebler and 

 gradually flickers out in the dying muscular fibres. 



In the human subject it is probable that true fibrillation 

 is (apart from treatment by cardiac massage, etc.) usually 

 if not invariably fatal, though it seems possible that such 

 recovery of separate though feeble ventricular beats too late 



