6.12.1913  -  12.12.2002

Books of N.M.Amosov

Digression. Heart

I simply must say a few words about the heart and how it works for readers with no medical background. The heart: how could you describe it? As a pump? As a hollow organ with walls of muscle to pump blood throughout the organism? And is there any need to describe it? For sure it is not the receptacle for the soul.

The anatomy of the heart and its main defects are shown in the drawing. The longitudinal septum (1,2) without openings divides the heart into the right and left halves. The transverse septum separates atria from ventricles and has valves in each half: on the right (3) a tricuspid one, on the left (4) a mitral valve. The dark venous blood short of oxygen and abundant in carbon dioxide flows into the right atrium (5) through the inferior (6) and superior (7) vena cava. The blood runs through the tricuspid valve during diastole — the period of relaxation — into the right ventricle (8) and from it during the systole — the period of contraction — into the pulmonary artery (9) through its valve (10).

In the lungs, the blood flows through pulmonary arteries into the capillaries, joining with air bubbles — the alveoli. That is where gas metabolism takes place — the blood gives off carbon dioxide and takes in oxygen. Further, the red blood, already arterial, is collected by four pulmonary veins (11) and runs into the left atrium (12). From there it flows through the mitral valve (4) into the left ventricle (13), and then through the aortic valve (14) into the aorta (15).

Through the arteries, the blood flows to all organs and reaches cells through capillaries. It takes C02 from them and gives them O2, acquiring a dark color, and then heads back to the heart through the vena cava, completing circulation.

The heart of a healthy person weighs about 300 — 450 grams, 5 — 7 grams per kilogram of weight, depending on the physical condition.

The function of the heart is to push the blood through the vessels to provide for gas metabolism between the cells and the air. During systole, the left ventricle creates a pressure of 100—200 mm Hg, the right, 15—20 mm Hg. In the atria, the pressure is rather low — about 5 mm Hg; in the right atrium, it is even lower than in the left one.

The valves open with the flow of the blood into the diastole, separating ventricles from arteries, and into the systole from the atria.

The contractions of the heart are rhythmic; the rate is regulated by its own nerve ganglions which are monitored by the central nervous system and hormones.

The capacity of the heart is expressed in the litres of the blood it pumps in one minute. The organism sets this capacity by the need for oxygen, the amount of which depends on physical load. The response of the heart is determined by its potential: state of health and training. Hypoxia — oxygen deprivation — is induced by a shortage of the blood for a given load. This being the case, a man has to stop to take a breath. Hypoxia may occur under pulmonary incompetence when the blood is not saturated with oxygen and the accelerated beat of the heart cannot compensate for this incompetence.

anatomy of the heart and its major flaws

Moderate hypoxia stimulates the work of the heart and, in this way, it is trained: a healthy heart reacts evenly, and in a sick heart, only those parts which are overloaded react. This causes hypertrophy which is manifested in the thickening of the ventricular wall.

A sick heart does not pump the amount of the blood necessary for the organism to function. Not infrequently, it is not sufficient even at rest. This results in so-called disturbed circulation. At the beginning, it is manifested in dyspnea, and then, in congestion of the blood in the liver and water retention, edema — and this means decompensation.

Diseases of the heart are classified in the following way: myocarditis — injury of the heart muscle — the myocardium. Valve failures — acquired and congenital. IHD — ischemic heart disease — the narrowing of the coronary arteries. Arrhythmia — the impairment of the cardiac rhythm. No doubt a combination of all these or several injuries is a frequent phenomenon.

Cardiologists deal only with pure myocarditis; surgeons have already taken IHDs and arrhythmia into their hands, whereas heart failure is solely our business. I will describe all this in detail.

A failure of the heart valves is such an impairment of their structure under which the cusps either do not close altogether — and this is the incompetence — or form an adhesion — stenosis. In the case of incompetence, part of the blood runs back and additional work is necessary to push it during the next systole. In the case of stenosis, abundant pressure should be created to "squeeze" the blood through the narrowed opening. In both cases, the corresponding ventricle is overloaded, which results in hypertrophy and disfunctioning with time. At the same time, the pressure is increased along the "inflow paths," that is before the overloaded ventricle, and this tells on the whole pulmonary or greater circulation which results in decompensation, left or right ventricular.

In this way, each failure means a change in the anatomy of the valve, the impairment of its function, the overloading and hypertrophy of one or both ventricles of the heart, a change of the blood pressure in the vessels, and then — insufficient circulation and hypoxy in the organs, and, finally, their secondary injury.

There are congenital and acquired heart failures. Congenital failures are extremely diverse. Besides injuries of the valves there are nonclosures (openings, defects) in the septa between the atria or ventricles, incorrect position of the septa themselves, the diaphragm within the cavities. There are dozens of different anatomic combinations. There are "white" failures when the arterial blood is added to the venous blood, and "blue" when the venous blood, through septal defects, mixes with the arterial and a child lives under a condition of constant hypoxia. The organism partially compensates for it by an abundant content of hemoglobin — up to 150 percent! This is manifested in the cyanosis of the face and hands.

The most complicated congenital failures lead to death in the first months of life. Many children with heart defects die between 10 to 15 years of age. Only a few of them live to maturity.

All congenital failures should be operated upon, although some of them are inoperative.

We distinguish between palliative (relieving, as we explain it to parents) and radical operations. The former mean anastomosis between the vessels and the creation of bypasses for the blood, partially compensating for the failure, and the latter, full restoration of the normal anatomy of the heart. This means intracardiac interference by "switching off" the heart and the lungs from circulation using the AIK machine or by hypothermia — cooling down to 28—30°C.

These are the most widely spread congenital failures we deal with: defects of the interatrial (a) or interventricular (b) septum. The blood from the left chamber is discharged into the right; the ventricle pushes it through the lungs into the left atrium — and once again, there is an escape into the right one. Therefore, a double or triple amount of blood flows through pulmonary circulation than through circulation as a whole. The spasm of the pulmonary arteries and their subsequent sclerosis (induration) develop as a compensation to this phenomenon. The pressure in the pulmonary arteries builds up to 100 mm Hg or more, resulting in pulmonary hypertension; children turn blue as a result of constant hypoxia and die of pneumonia and other ailment. Therefore, they should be operated upon at an early age — between 3 and 6 years.

The principle of this operation is to switch on the AIK machine and close the opening (defect) with a synthetic patch.

Pulmonary and aortic stenoses are manifested in the narrowing of the valves of the pulmonary artery or the aorta. The pressure in the corresponding ventricle increases, developing into hypertrophy, and later, into irreparable weakening. During the operation, the opening of the valve is expanded to the utmost.

I will draw your attention to one of the most complicated heart failures — Fallot's tetralogy.

This is a "blue" failure: the entry into the pulmonary artery is narrowed and there is a defect of the interventricular septum. The pressure in the right ventricle due to pulmonary stenosis is higher than in the left one, and the venous blood is expelled from the right to the left; it brings less oxygen to the lungs and gets into the left ventricle and aorta, causing hypoxia. To correct the failure, the entry into the pulmonary artery should be expanded, and the defect in the septum should be closed. The palliative operation creates an artificial Botallo's duct (d) — communication between the aorta and the pulmonary artery — to increase the flow of blood through the lungs and to saturate the blood with oxygen.

The most simple congenital failure is Botallo's duct patency and congenital narrowing (coarctation) of the aorta (e). They are easily operated without the AIK machine. However, the operation cannot be postponed, since hypertension (increased pressure) develops with the Botallo's duct in the lungs and there is coarctation of the aorta.

Acquired failures are a result of rheumatism or septic endocarditis. Rheumatism is a complicated disease, related to infection (most frequently at an early age) and the development of a peculiar allergic reaction to some microbe, with resulting damage to all the connective tissue. Most affected are the valves of the heart; less affected are the myocardium and vessels in various organs, and to an even lesser extent, the joints. "Rheumatism licks the joints and bites the heart." The inflammation in the valves begins with their enlargement, followed by cicatrization, deformation and accretion of the cusps, and ends with the formation of calcium salt deposits. The impairment of the function of the valve begins with incompetence and may end with stenosis. The mitral valve is most often affected — mitral incompetence, mitral stenosis or a combined mitral failure.

The impairment of circulation mainly affects the lungs — dyspnea or hemoptysis — then it spreads to the circulatory system as a whole resulting in an enlargement of the liver, urine retention, and edemadecompensation. In the heart itself, the mitral failure is manifested in the hypertrophy of the ventricles, and later, in the distention of all heart cavities. Its weight increases two to four times as compared to normal.

A so-called mitral commissurotomy (dilation of the opening with a special instrument on the beating heart) is performed under mitral stenosis while the cusps are not yet covered with calcium salts. In case of incompetence or stenosis with calcification, the valve must be replaced with a prosthesis — an artificial valve — a rubber ball or a semisphere, enclosed by four wires and resting on a saddle. To implant it, artificial circulation is used.

The arterial valve is affected in the same way as the mitral one, but approximately half as often. Since all the load is placed on the strong left ventricle, the failure is compensated for a rather long time and has almost no effect on the way the patient feels. But when the ventricle gives out, decompensation progresses rapidly. A prosthetic valve is required for any aortal failure.

Failures of the tricuspid valve are most often manifested in incompetence as a result of the distention of the right ventricle at a later stage of mitral failure, but a direct injury of the valvular cusps is also possible. To correct it, the valvular ring must be narrowed by a special method, most often this poses additional interference in correcting the main mitral failure with the AIK machine.

Coronary artery disease is the most frequent heart disease. The cause is sclerosis of the vessels resulting from improper diet, smoking, and lack of physical exercise. The essence of the pathology is the narrowing of the coronary arteries feeding the myocardium by accumulation of sclerotic plaque and the enlargement of the wall, occasionally resulting in the complete closing of the lumen. The outcome is myocardial infarction, a grave disease familiar to many. Obviously, all the coronary arteries cannot be fully replaced by surgery all of them are affected. But when the lumen is narrowed along a limited section, the blood may be directed into a bypass with a piece of a vein, one of which is sewn into the aorta, and the other into the coronary artery below the narrowing. This operation is known as coronary artery shunting. These operations eliminate pain and prolong life, although do not arrest the development of sclerosis. Since angina pectoris can be treated with drugs, this operation is not a generally accepted method as in the case of heart failure, and therefore, our cardiologists are not apt to send such patients to heart surgeons.

Treatment of cardiac arrhythmias is another area of heart surgery. Up till now, we have been sewing in electric pace-makers under blockades of the heart when communication is interrupted between the main rhythm-setter, the sinus node, and the other sections of the conducting system of the heart. This is manifested in a pulsus tardus — only forty pulses a minute — and sometimes, brief heart arrest when the patient looses consciousness. The majority of those who suffer from this condition are elderly. The pace-maker is an electric pulse generator, two match-boxes in size. It is sewn in under the skin and is connected by wires to the surface or the interior of the ventricles through the lumen of the vena cava. Unfortunately, each two or three years the pace-maker must be replaced because the batteries run down.

I will limit myself to this minimal information on cardiosurgery. Special terms will be explained during the course of my narration.