286 Z. Fejfar 



failure inhaling 50 per cent oxygen plus 4 per cent carbon 

 dioxide for 30 minutes (Foldi et ah, 1956). According to these 

 authors renal changes are brought about by hypoxia in the 

 brain. 



It is improbable, however, that every case of heart failure 

 is accompanied by cerebral hypoxia. The renal changes are 

 manifested, as shown above, in left-sided failure. The results 

 of Scheinberg (1950) indicate a decreased blood flow through 

 the brain in heart failure together with a rise in cerebral 

 vascular resistance. If the cerebral supply of oxygen is really 

 insufficient, we might expect quite the reverse: a diminution 

 of cerebral vascular resistance and an increase in cerebral 

 blood flow. This was actually demonstrated in man during 

 experimental hypoxaemia by Kety and Schmidt (1948). 



We are of the opinion that the heart itself may be the 

 starting point for the haemodynamic functional changes 

 in heart failure, and in all situations in which CO is inade- 

 quate for the requirement in tissues, i.e. where oxygen utiliza- 

 tion in tissues increases (Fejfar, 1956, 1957, 1958). The basis 

 for this hypothesis will be briefly summarized: 



(a) Myocardial utilization of oxygen is, even with physical 

 inactivity in healthy subjects, greater than that by the other 

 important organs of the body. Every rise in oxygen con- 

 sumption or utilization in tissues (muscular effort, anaemia, 

 mitral stenosis, etc.) is associated with coronary vasodilation, 

 an increase in the coronary fraction of CO, and vasoconstric- 

 tion in the kidneys. 



(b) We have demonstrated that during the inhalation of 

 oxygen a normal CO in a healthy subject, or in compensated 

 patients, either does not change or decreases, while a low 

 cardiac output in heart failure increases (Fejfar, 1957; 

 Fejfar et al., 1958a). 



(c) Gomori and co-workers (1954), in experiments cited above, 

 did not find an elevation of CO during isolated hypoxia of the 

 brain. On the other hand, when the isolated head of a dog 

 was perfused by arterial blood and the trunk supplied with 

 hypoxaemic blood (the dogs inhaled a mixture with a low 



