128 READINGS IN BIOLOGICAL SCIENCE 



point of heart failure can often be delayed for many years, even into old 

 age, by following the doctor's advice and leading a life of moderation in 

 all things — in work and play, in eating, in smoking, in emotional reactions. 



The Aging Heart 



CORONARY HEART DISEASE 



Heart disease caused by disease of the coronary arteries, which have the 

 job of supplying the heart muscle itself with blood, is most common after 

 age 50. Thickening of the coronary arteries (coronary arteriosclerosis), 

 usually associated with hypertension, is the chief cause of coronary disease. 

 Its harmful effect on the heart is explained by the reduction of the blood 

 supply of the heart muscle (the myocardium) which occurs when the 

 coronary arteries are narrowed or blocked. However, the reserve strength 

 of the heart muscle and its blood supply are both so great that they are 

 not easily exhausted. Many people are able to live quite comfortably with 

 coronary heart disease if they are careful not to place too great a strain 

 on their hearts. With the object not only of prolonging their lives but 

 also of enabling them to be useful and happy, the physician helps them to 

 strike a balance between too many and too few restrictions. The main 

 thing to strive for is equanimity. Some people with a comparatively small 

 amount of heart damage and disability make themselves worse through 

 sheer nervousness. 



A?ighM Pectoris. The inability of the coronary arteries to perform their 

 duty properly is made plain by a symptom so important that it is often 

 regarded as a disease in itself. This symptom is called angina pectoris. 

 Angina pectoris is a painful, strangling, oppressive sensation under the 

 breastbone, frequently radiating down the arms, which is brought on by 

 exertion and lasts for only a few minutes. It is not like any ordinary pain 

 in the chest, and a person who has had it once seldom needs to be persuaded 

 to see a doctor. 



Coronary Thrombosis. The most serious "accident"which may occur 

 in coronary disease is the sudden closing (occlusion) of a coronary artery 

 by a blood clot (thrombus). It causes severe crushing pain in the chest, 

 accompanied by weakness, pallor, and sweating, which persists in spite 

 of rest. Sometimes the pain is mistaken for acute indigestion. A doctor 

 should be summoned at once, because this is a real heart emergency. How- 

 ever, the great majority of persons survive the first attack of coronary 

 thrombosis, and most of the survivors live for many years. After the dam- 

 age done to the heart muscle has had opportunity to heal through a long 

 rest in bed, the heart has an excellent chance to recover sufficiently to 

 allow normal or near-normal activities. 



