Heart Disease

(to be continued)

Heart disease is not one but many diseases. Nor is the heart alone involved. The blood vessels and the kidneys, and sometimes other organs, are also affected. When we talk about heart disease, we usually mean cardiovascular or cardiovascularenal disease, “cardio” for heart, “vascular” for blood vessels, “renal” for kidneys. When damage or change occurs in any part of this system, it is reflected in the other parts.

The net effect of cardiovascular disease is to diminish the flow of blood and the delivery of oxygen, essential to life, to the tissues. The situation is most dangerous when the blood flow to the heart muscle or brain is impaired. What is commonly called a heart attack is the result of closure or clogging of one or more of the little arteries that serve the heart. When a brain artery breaks or clogs, the condition known as stroke or apoplexy or cerebral vascular accident occurs.

Cardiovascular disease in later life is a degenerative disease. Effective treatment and management can prolong life and make it comfortable.

Great progress has been made in the diagnosis, classification, and treatment of heart disease. Improved drugs and more daring surgery have both helped, along with a better understanding of the nature of the disease. Even heart attacks are more effectively controlled. They are not sentences to permanent invalidism. The average length of life after a heart attack is at least 10 years.

What kinds of heart disease are there? There at least 20 kinds of organic heart disease that actually affect the heart muscle, the valves of the heart, or its inner or outer lining. There also a number of functional disorders of the heart in which its function or action is altered, or in which symptoms are referred to the heart, but in which no actual damage to or lesions in the heart are discoverable. Heart trouble may be primary, or secondary to other diseases.

The most common and serious forms of organic heart disease are those affecting the coronary arteries, which supply blood to the heart. These diseases are usually associated with high blood pressure (hypertension) and hardening of the arteries (arteriosclerosis). A heart attack is usually a case of coronary thrombosis. Heart failure may be a late consequence of any of these conditions, or others. This group of heart troubles is predominantly, but not exclusively, associated with the middle or later years of life.

Infections present a second class of causes of organic heart disease. Rheumatic fever, or rheumatic heart disease, associated with certain streptococcal (“strep”) infections, once headed the list. Diphtheria, tuberculosis, typhoid, and other fevers can injure the heart. Fortunately, these diseases can usually be treated (prevented) before they cause heart damage. Before the advent of antibiotics, bacterial endocarditis, in which the inner lining of the heart, the endocardium, is directly infected, was usually fatal. Now, with penicillin and other drugs, it is curable in 80% or better of the cases. The outer membrane, or sac, that contains the heart may also become inflamed, then thicken and harden so that it binds the heart too tightly and interferes with its work. This condition, known as constrictive pericarditis, can be relieved by cutting away strips of the scarred and hardened tissue. Infections are chief cause of heart disease in childhood and early adult life.

Congenital heart defects, which develop before birth and are usually discovered shortly thereafter, account for about 2% of all heart defects. “Blue babies” have a congenital defect that permits the bluer venous blood to mix with arterial blood.

Other forms of organic heart disease are associated with or the result of poor functioning of the endocrine glands, especially the thyroid gland; with chronic lungs disease that overtaxes the heart, with severe anemias; with some nutritional diseases, notably beriberi; with poisoning from heavy metals or kidney wastes (uremia); and with direct injuries or wounds to the heart.

Functional disorders of the heart include such conditions as heart murmurs; palpitation; premature beats; skipped beats; rapid beating, up to 250 beats a minute (paroxysmal tachycardia); slow beating, under 60 beats a minute (bradycardia); irregular rhythmus; and rapid flutter. Other functional disorders are heart disturbances of psychic or emotional origin. In these cases the patient fears and believes that he has heart disease and develops symptoms associated with it, such as palpitation, shortness of breath, extreme fatigue, and dizzy spells. This condition has many names: cardiac neurosis; effort syndrome; and neurocirculatory asthenia (weakness of the nervous and circulatory systems). Here the doctor’s job is to persuade the patient that he does not have organic heart disease. Psychiatric treatment is sometimes necessary.

Because heart disease can be so specifically classified and so much more accurately diagnosed today, more specific and effective treatment is possible for each kind of heart disease. Not so many years ago coronary thrombosis was often diagnosed as acute indigestion.

What is heart attack? Heart attack is the popular term for what physicians call coronary thrombosis (also coronary occlusion, coronary closure, and myocardial infarction). Heart attacks can be suddenly fatal, but the great majority – an estimated 85% – is not. The patient recovers under proper treatment and goes on to live many useful years. The younger the victim, the greater is his life expectancy.

Although the attack is sudden, the conditions underlying it have been developing for years. For reasons still obscure the inner linings (intima) of the arteries gradually become thickened and roughened, a condition known as atherosclerosis. The coronary arteries, which supply blood to the heart, are subject to these changes more than other arteries. The narrowed channel slows down the flow of blood, and the roughened surface provides greater opportunity for a blood clot to form on the wall. This stationary clot is called a thrombus. At the moment such a clot cuts off the blood supply to part of the heart the heart attack occurs.

If a large coronary artery is suddenly closed up, the attack may be fatal. However, in most cases, the blood detours around the blocked artery by way of other blood vessels that compensate for the blockage. This is called collateral circulation, and it is the road to recovery. The immediate treatment of a heart attack is to ward off very rapid movements of the ventricles of the heart (called ventricular fibrillation – the greatest risk to life in a heart attack). Next step is to relieve pain, then treat shock, and provide necessary oxygen.

It takes about a month for a new circulation pathway to be established. During this period the heart’s work must be kept to a minimum, so the patient must remain at rest in bed. Oxygen may be given through an oxygen tent or mask. A take-it-easy, convalescent period should follow two to three of bed rest. If the patient avoids excessive strain on the heart during the healing process, recovery usually proceeds to the point where he can resume his normal life. In some cases, however, the damaged area of the heart muscle, gradually replaced by scar tissue, is so large that the heart is weakened and symptoms of distress appear.

Most heart attacks occur while a patient is at rest in bed or working quietly. Vigorous exercise by a person unaccustomed to it may perhaps precipitate the final blood clotting in the coronary artery, but even if he had not exercised strenuously, the chances are the clot would soon have appeared. Hence it is foolish to indict any single event as the cause of a heart attack.

The condition leading to heart attack is atherosclerosis in the lining of the coronary arteries, and the reasons for this are still uncertain. The deposit of fatty substances, notably cholesterol, under the lining appears to be a critical factor, but there is no agreement yet on why this takes place. Since heart attacks are far more common in men than in women, it has been said, “Women deposit their fat under the skin, while men deposit it in the walls of their coronary arteries”. Because the body itself is able to manufacture large amounts of cholesterol from foods that contain none, the use of fat-free or other special diet cannot be depended on to prevent atherosclerosis or heart attack.