426 ILLINOIS STATE ACADEMY OF SCIENCE 



From these observations, we may conclude that the 

 vital capacity may be of value in suggesting pulmonary 

 complications in diseases outside the respiratory tract. 



VITAL CAPACITY OF THE LUNGS IN HEART DISEASE 



It has long been known that the vital capacity of the 

 lungs is frequently decreased in heart disease. Peabody 

 and \Ventworth confirmed this fact by making 224 ob- 

 servations on 124 patients, and showed in a striking 

 manner that the clinical condition of the patient, and 

 more especially the tendency to dyspnea, varied directly 

 with the degree of diminution of the vital capacity. They 

 subdivide the cases into four groups, basing their classi- 

 fication on the degree of diminished vital capacity. 



Group One consists of cases with a vital capacity of 

 90 per cent or more of the normal. Very few of these 

 patients complained of any symptoms referable to their 

 hearts. Many of them entered the hospital for other 

 diseases, and the cardiac condition was discovered in the 

 course of the routine examination. The vast majority 

 of the patients in this group were able to work without 

 much restriction. Only two of 25 patients were prevented 

 from working on account of their cardiac condition. It 

 is evident that cardiac patients, with a vital capacity of 

 90 per cent or more of the normal, are almost always in 

 a good state of compensation. They do not suffer from 

 dyspnea after exertion, and if they are prevented from 

 performing their usual task, it is usually on account of 

 cardiac pain or other disturbances. 



Group Two consists of cases in which the vital capacity 

 is 70 to 90 per cent of the normal. A history of dyspnea 

 on moderate exertion was a symptom usually given by 

 these patients, but the majority could work and lead a 

 satisfactory, though somewhat restricted life. 



It may be said, in general, that cardiac patients with 

 a vital capacity of from 70 to 90 per cent of the normal 

 may have marked heart lesions, but usually are able to 

 lead satisfactory, but restricted, lives. Almost all of 

 these patients give a history of dyspnea, and have a dis- 

 tinctly limited cardiac reserve ; they may be regarded as 

 border-line cases in which the activities must be some- 



