ducting apparatus; that is, to fibrillary tears in the myocardium.1 15. By the teleröntgen method, C. S. Williamson2 has demonstrated that (a) the normal heart responds to any exercise within its power by a diminution in size; (b) about 50 per cent. of pathologic hearts, which are in good compensation, respond to exercise within their power, by a diminution in size; (c) approximately 50 per cent. of the pathologic hearts, which manifest but a low grade of broken compensation, respond in the same manner by some diminution in size. Permanent Result of Prolonged Muscular Exercise and Cardiac Overstrain.-There is less argument concerning the ultimate result of over-exertion on the heart than upon the immediate effect of physical exertion. The following points, however, seem to be clearly established: 1. Severe exertion from violent and prolonged efforts may reach a point beyond the capacity of the heart muscle to produce a complete systole. This results in the typical symptoms of acute cardiac dilatation. The prognosis. here depends upon whether the heart was previously sound or not. The weakened condition of the cardiac muscle is shown after the cessation of effort by its inability to return to its normal size. 3 2. Infectious diseases especially tend to weaken the myocardium. For this reason, severe athletic contests should be avoided by those suffering with, or convalescent 1 L. Shumacher and W. S. Middleton, Jour. A. M. A., Apr. 11, 1914, lxii, No. 15, p. 1136. 2 Am. Jour. Med. Sci., 1915, cxlix, No. 4. K. Blandenburg, Med. klin., Sept. 3, 1914, x, 37. from, acute infectious diseases, even often mild cases of tonsillitis and grippe. 3. Immoderate physical efforts lead to hypertrophy of the heart. Athletic training leads first to physiologic hypertrophy, but if prolonged and overdone it leads to hypertrophy plus dilatation. The degree is variable and may frequently lead to marked valvular insufficiency.1 4. Functionally, the hypertrophied heart, even when dilated and giving distinct evidence of valvular insufficiency may prove more fitted to carry the man through a severe athletic contest than a normal heart would be. On the other hand, acute cardiac dilatation occurs more frequently in athletes and men habituated to severe muscular strain than in average men, and the ultimate effects are more prolonged and severe.2 5. Hearts known to be diseased may respond in the normal manner, as shown by a reduction in size after the cessation of moderate exertion, while hearts that give a distinct systolic murmur may withstand a Marathon race better than hearts which are apparently nearer normal.3 6. There is reason to believe that for normal human activities an "athletic" heart is distinctly disadvantageous.* 7. Experience teaches that much good can be secured by careful examination of the heart before and after moderate exercise, of all those who desire to enter severe athletic contests. Failure to obtain a normal reaction should bar anyone from such contests. Even those apparently standing such contests well should have the heart and blood 1 Shumacker and Middleton, loc. cit. 2 Shumacker and Middleton, loc. cit. Shumacker and Middleton, loc. cit. pressure examined at frequent intervals during training, to detect possible overstrain. Continued overstrain even when slight may weaken a normal heart muscle instead of strengthening it. This appears to be particularly true among young boys (of immature development) who have been found to develop persistent cardiac changes the result of prolonged overstrain. 8. Carefully collated statistics1 show that athletes die from the following diseases in their order of frequency: cardiac disease, tuberculosis, typhoid fever, pneumonia and Bright's disease. 1 R. E. Coughlin, Med. Rec., Aug. 8, 1914, lxxxvi, No. 12. CHAPTER XI BLOOD-PRESSURE IN CHILDREN Reference to the normal blood-pressure values in children has already been made in the section devoted to normal blood-pressure and the factors causing its variation, so that further discussion of this portion of the subject is omitted here (see page 115). In studying the difference between the average pulse pressure in children and in adults, G. S. Melvin and J. R. Murray,1 employing a Pachon oscillometer with an 8-cm arm-band, found an average variation of about 10 mm., giving their average as 46 mm. in adults as compared with 35.7 mm. in children. This is in close accord with the at present accepted belief that the pulse pressure is equal to about one-third the systolic pressure. The same factors which influence blood-pressure from time to time in adults act with even greater force upon blood-pressure in children. It is generally believed that all things being equal the weight and size of the child, rather than the exact age, is the important factor in determining the actual systolic pressure level. Orthostatic Albuminuria in Children.-The occurrence of this condition and its relation to and effect upon bloodpressure is of considerable interest and importance to the 1 Brit. Med. Jour., Apr. 17, 1915, 1, 2833. pediatrician, as here the blood-pressure test will serve to differentiate this type of urinary disturbance from those of more serious import. In this connection the occurrence of this type of albuminuria is rather interesting. Thus K. Bugge1 examined over a thousand school children and found albumin present in 14.9 per cent. in which it had no relation to cardiovascular or renal conditions. In demonstrating the effect of physical exercise upon this condition Bugge was able to demonstrate the development of transient albuminuria in 20 per cent. of healthy boys after gymnastic exercise. This type of albuminuria is sometimes seen in convalescents and as an accompaniment of cardiovascular weakness in the presence of low blood-pressures, and is here probably a reflection of an abnormal reaction of the vasomotor relations of the kidneys. Bass and Wessler's2 observations show that the bloodpressure of children suffering from orthostatic albuminuria differs but little from that of normal children, in spite of an apparent vasomotor insufficiency, which many of these children show. Blood-pressure reactions, both in the upright and in the recumbent postures and after exercise, revealed no characteristic anomaly. Nor were they able in any way to correlate the blood-pressure findings with the findings in regard to the size and strength of the heart or the pulse rate. They do not believe that children with orthostatic albuminuria, accompanied by cardiovascular symptoms, can be differentiated by means of blood-pressure tests. 1 Norsk. Magazin. f. Legevid, December, 1914, lxxiv, 12. 'H. H. Bass and H. Wessler, Arch. Int. Med., January, 1914, xii, 1. |