82 



were no adequate microscopic post-mortem findings to 

 account for the fatal issue, apart from marked alterations 

 present in the branches of the a-v bundle in the shape of 

 fatty infiltration or replacement, the Purkinje fibres being 

 beset with fatty droplets, etc. 



Sapegno,^* from a study of seventy-two cases, inferred 

 that rapid unexpected death may be due to acute or chronic 

 lesion of the bundle fibres, the acute changes being pre- 

 dominant in these fibres when both they and the ventricular 

 myocardium were affected. He cites an instance of sudden 

 death in a girl twelve days after recovery from typhoid 

 fever, not associated with the acute changes sometimes seen 

 in the myocardium after typhoid, but with lipomatosis in 

 the bundle fibres — the cell substance being largely replaced 

 by fat — from the point of division of the main stem to the 

 point where the two main divisions decrease rapidly in size. 

 Monckeberg^" described two cases of sudden death associated 

 with lesions of the Purkinje fibres. One was a diphtheria 

 case, where no gross changes were found in the myocardium, 

 but fatty changes were shown by staining with Scharlach B 

 in the main stem, branches, and subdivisions; the myocar- 

 dium was fat-free. In the other case (trephining of skull, 

 etc.) there were more pronounced fatty changes in the bundle 

 fibres than in the myocardium, though some of the Purkinje 

 fibres seemed to have remained normal. 



It need hardly be recalled that several observers have 

 described certain abnormal features in electrical records 

 from the heart as being indicative of defective conduction in 

 the main branches, bundle block (Lewis and others), or in 

 the intraventricular Purkinje network (arborization block) — 

 bizarre ventricular complexes with notching or splintering 

 of the deflections, prolongation of the duration of the Q R S 

 group oscillations, inversion of the T wave, etc., in addition 

 to a remarkably low altitude of the curves in arborization 

 block. (Oppenheimer and Rothschild,'^^ Carter,'*^ Willius," 

 and others.) 



Exciting Causes of Ventricular Fibrillation. 

 In the many observed cases where all the facts point to 

 ventricular fibrillation as the immediate cause of sudden 

 death the common association of muscular exertion or 

 emotional excitement is notable. The ever-recurring reports 

 of sudden deaths during or shortly after exertion, in persons 

 who up to the fatal issue had been able to pursue their usual 

 avocations, emphasize the importance of the conditions 

 attendant on muscular effort — those involving an increased 

 demand on the powers of the heart and more or less stress 

 on the organ. This is brought about in various ways : by 

 the augmentation of rate and force and irritability through 

 the agency of the cardiac nerves (diminution or suspension of 

 vagus control and excitation of the cardiac sympathetic aug- 

 mentor fibres), increased arterial pressure presenting greater 

 resistance to the pumping out of the ventricular contents, 



