The heart is a four-chamber organ, consisting of two atria and two ventricles. The atria are divided by the interatrial septum into left and right. The left and right ventricles of the heart are separated by the interventricular septum. Blood in the heart normally moves only in one direction, which is ensured by the functioning valvular apparatus of the heart, consisting of four valves: tricuspid, pulmonary, mitral and aortic.
- The tricuspid valve is located between the right atrium and the right ventricle and allows unidirectional blood flow from the right atrium to the right ventricle.
- The pulmonary valve is located at the exit of the right ventricle and allows blood to flow into the pulmonary artery.
- The mitral valve is located between the left atrium and the left ventricle, through it blood flows from the left atrium to the left ventricle.
- The aortic valve is located at the exit of the left ventricle and allows blood to flow into the aorta and further into the systems and organs of the body.
general description
Congenital heart defects (heart defects) are an abnormal structure of the heart chambers, large vessels or valves (combinations are not uncommon) due to genetic predisposition, intrauterine development disorders, infectious, autoimmune, metabolic and other diseases, injuries received by the mother during pregnancy.
Valve lesions can be congenital (due to disorders of intrauterine development) or acquired, that is, occurring during life under the influence of diseases, infections or injuries. In most cases, complex congenital defects require surgical correction in both children and adults.
Pulmonary valve
Also known as the pulmonary valve. The structure of the pulmonary valve is similar to that of the aortic valve. The valves have a semilunar shape; normally there are three of them (anterior, left and right). Similar to the valves, the sinuses are called sinuses, which are united with the pulmonary trunk through an arched ring (sinotobular junction). Like other valves, the pulmonary valve also has a fibrous ring and a commissure.
Associated diseases: pulmonary valve stenosis, pulmonary valve regurgitation.
What are the types of congenital heart defects?
- pulmonary valve stenosis
- stenosis of the aortic valve, aortic orifice, subvalvular stenosis;
- mitral stenosis - narrowing of the bicuspid atrioventricular valve;
- Mitral valve insufficiency - incomplete closure of the bicuspid atrioventricular valve;
- Mitral valve prolapse - excessive length of one or two valve leaflets;
- aortic valve insufficiency;
- tricuspid stenosis;
- triscupidal insufficiency;
- defects of the interatrial and interventricular septum;
- anomalies in the development of heart cavities: Ebstein's anomaly, single atrium, single ventricle;
- transposition of large vessels - aorta and pulmonary artery;
- tetralogy of Fallot;
- open arterial (Botallov) duct;
- coarctation of the aorta;
- The most common congenital heart defect is an abnormal communication between the atria—atrial septal defect.
Aortic valve
The tricuspid valve, located at the mouth of the aorta, separates the cavity of the left ventricle from the aorta. Behind the three semilunar cusps (right coronary, left coronary and posterior non-coronary) of the aortic valve are dilated pockets of the aortic ostium, called sinuses of Valsalva. The right coronary artery arises from the right coronary sinus, and the left coronary artery arises from the left coronary sinus. The area where all three valves meet is called the commissure.
The opening and closing of the aortic valve is a passive pressure-controlled mechanism, unlike the mitral valve.
The tissue of the aortic valves is stretched as a result of counteraction during diastole, and elastin elongates and stretches. Therefore, normally the aortic valve leaflets are quite flexible and durable, able to withstand systemic pressure. During the systole phase, the release of elastin ensures relaxation and shortening of the leaflet. Optimal valve function requires perfect alignment of the three return points.
Associated diseases: aortic regurgitation (also called aortic regurgitation), aortic stenosis.
Diagnosis and treatment of heart disease
Cardiac surgeons can recognize and eliminate the defect in a timely manner. In most cases, x-ray surgeons close the defect using catheter technology without resorting to an incision.
- A defect may appear between the ventricles of the heart - a ventricular septal defect.
- Often the defects are combined with anomalies of the valvular apparatus of the heart or large vessels.
The valvular apparatus of the heart consists of four valves: mitral (bicuspid), tricuspid (three-cuspid), aortic and pulmonary valve. The functioning of the heart depends on the coordinated and correct functioning of these structures.There are two main types of valve disease: valve insufficiency and stenosis.
When there is insufficiency, the valve leaflets do not close completely, leaving a gap through which blood is thrown in the opposite direction to the normal direction. And with stenosis, the valves do not open completely, preventing normal blood flow. Isolated lesions of the heart valves are relatively rare; they are very often observed in other congenital heart defects. For example, a bicuspid acortical valve is often found in people with a patent ductus arteriosus. With this defect, part of the blood (rich in oxygen) from the aorta, which is not closed after the birth of the child, enters the pulmonary artery, causing an overload of the right side of the heart. In children and adolescents, such an abnormal message is most often eliminated without surgery, by installing a “plug” through the catheter.
- Another congenital malformation is stenosis of the descending aorta.
In the thoracic segment, the aorta is attached to the posterior wall, closer to the spine. At this point, the aorta is sometimes significantly narrowed, and the internal organs do not receive enough arterial blood. Previously, this condition, called coarctation of the aorta, could only be corrected with surgery. But today, in most cases, narrowing during coractation of the aorta is eliminated by balloon dilation and installation of a stent frame. It should be emphasized that if valve stenosis is an isolated lesion, it is often eliminated by balloon expansion, in a minimally traumatic way.
Operation of the valve apparatus
In normal condition, the valves function in strict order, which allows the chambers of the heart to contract correctly and eject blood in the required volume. There are four main stages in the operation of the valve apparatus:
1. The atrioventricular valves (mitral and tricuspid) open, as a result of which blood rushes from the upper parts of the heart to the lower ones.
2. When the ventricles are filled, the pressure in their cavity increases, as a result of which the valves close. When the ventricles contract, blood fills the atria again (venous - right and arterial - left).
3. The aortic and pulmonary valves open. This also occurs under pressure when the ventricles contract and blood is pushed into large vessels and follows either to the lungs (from the right ventricle) or to all organs and tissues (from the left ventricle).
4. During relaxation of the ventricles, the pulmonary and aortic valves close. At this time, the atrioventricular valves open and blood again enters the ventricles from the atria for the next release into the bloodstream.
How do heart valve diseases manifest?
Most often, patient complaints are nonspecific: shortness of breath, rapid pulse, arrhythmia, fatigue, cyanosis, dizziness.
The severity and nature of symptoms depend on the location of the affected valve. With valve defects of the left half of the heart (mitral and aortic), the lungs are primarily affected, because Blood stagnates in their vessels, which manifests itself as shortness of breath. There are also signs of insufficient blood supply to all organs and systems, primarily the brain and the heart itself. Dizziness, fainting, and angina occur. If the functioning of the valves of the right half of the heart (tricuspid and pulmonary valves) is disrupted, blood stagnates in the vessels of the systemic circulation, i.e. all organs except the lungs are affected. Swelling of the legs and feet, ascites (fluid in the abdominal cavity), enlargement of the liver, etc. develop (LIVER INCREASES, ETC.).
Heart valve defects are dangerous due to their complications and impact on the body, so the main prevention of pathological conditions is regular examinations and treatment of diseases leading to the formation of valve defects.
Types of valves used in prosthetics
Biological valves
They can be made from animal or human tissues (heterografts, homografts, autografts). Biological valves may contain some artificial components to provide valve support and placement. The main advantage of such a valve is that there is no need for lifelong anticoagulant therapy (constant strict use of drugs that significantly thin the blood and require constant blood tests), and the main disadvantage is its limited service life (10-15 years).
Mechanical valves
They consist entirely of mechanical elements (titanium and pyrolytic carbon) and are designed to replace the patient's own valve functions. The mechanical valve is very reliable and durable, designed for many years of full-fledged operation, which is the main advantage, but requires the patient to constantly take anticoagulants.
The Center for Cardiac Surgery and Cardiology provides assistance to patients with valvular pathology of varying complexity, including one-, two- and three-valve replacement with biological and mechanical prostheses of Russian and foreign production, elimination of valvular insufficiency using a variety of plastics (plasty on a support ring, tri- and quadriangular resection leaflets with annuloplasty according to De Vega, Batista) of the valve apparatus, restoration of the chordal apparatus by prosthetics of the mitral valve chords, etc. The main direction in surgery of valve pathology is aimed at increasing the number of reconstructive operations on the valve apparatus and reducing valve replacement.
The Clinic offers surgical treatment of heart valves in combination with other diseases, such as coronary heart disease, atrial fibrillation (atrial fibrillation).
Functions of the mitral snort
This leaflet heart valve is located in the left chamber between the ventricle and atrium. When open, it performs the function of being the entrance for blood flow into the ventricle. When the heart muscle is in the systolic phase, the valve blocks the backflow of blood.
The medical history of the field of cardiology indicates that due to its structure, the mitral snort (bivalve) is the first to be recognized on ultrasound. Due to its anatomy, it reflects the ultrasound signal well. Due to the fact that the anterior valve of the snort has good plasticity and mobility, medical specialists can examine in detail the structure of the valve apparatus.
National Society for the Study of Atherosclerosis
In order to talk about diseases of the cardiovascular system, it is necessary to understand its structure. The circulatory system is divided into arterial and venous. Through the arterial system, blood flows from the heart, through the venous system it flows to the heart. There are large and small circles of blood circulation. The great circle includes the aorta (ascending and descending, aortic arch, thoracic and abdominal sections), through which blood flows from the left side of the heart. From the aorta, blood enters the carotid arteries that supply blood to the brain, subclavian arteries, blood supply to the arms, renal arteries, arteries of the stomach, intestines, liver, spleen, pancreas, pelvic organs, iliac and femoral arteries, and blood supply to the legs. Blood flows from the internal organs through veins that drain into the superior vena cava (collects blood from the upper half of the body) and the inferior vena cava (collects blood from the lower half of the body). The vena cava drains into the right heart. The pulmonary circulation includes the pulmonary artery (through which, however, venous blood flows). Through the pulmonary artery, blood enters the lungs, where it is enriched with oxygen and becomes arterial. Through the pulmonary veins (four), arterial blood enters the left heart.
The heart pumps blood - a hollow muscular organ consisting of four sections. These are the right atrium and right ventricle, which make up the right heart, and the left atrium and left ventricle, which make up the left heart. Oxygen-rich blood coming from the lungs through the pulmonary veins enters the left atrium, from there into the left ventricle and then into the aorta. Venous blood enters the right atrium through the superior and inferior vena cava, from there into the right ventricle and further through the pulmonary artery into the lungs, where it is enriched with oxygen and again enters the left atrium.
There are pericardium, myocardium and endocardium. The heart is located in the cardiac sac - the pericardium. Cardiac muscle - the myocardium consists of several layers of muscle fibers; there are more of them in the ventricles than in the atria. These fibers, contracting, push blood from the atria into the ventricles and from the ventricles into the vessels. The internal cavities of the heart and valves are lined by the endocardium.
- Right coronary artery
- Anterior descending artery
- Ear
- Superior vena cava
- Inferior vena cava
- Aorta
- Pulmonary artery
- Branches of the aorta
- Right atrium
- Right ventricle
- Left atrium
- Left ventricle
- Trabeculae
- Chords
- Tricuspid valve
- Mitral valve
- Pulmonary valve
Valve apparatus of the heart
Between the left atrium and the left ventricle there is a mitral (bicuspid) valve, and between the right atrium and the right ventricle there is a tricuspid (three-leaf) valve. The aortic valve is located between the left ventricle and the aorta, the pulmonary valve is between the pulmonary artery and the right ventricle.
Work of the heart
From the left and right atria, blood flows into the left and right ventricles, while the mitral and tricuspid valves are open, the aortic and pulmonary valves are closed. This phase in the work of the heart is called diastole. Then the mitral and tricuspid valves close, the ventricles contract and through the opened aortic and pulmonary valves, blood rushes into the aorta and pulmonary artery, respectively. This phase is called systole, systole is shorter than diastole.
Conduction system of the heart
We can say that the heart works autonomously - it itself generates an electrical impulse that spreads through the heart muscle, causing it to contract. The pulse must be generated at a certain frequency - normally about 50-80 pulses per minute. In the conduction system of the heart, the sinus node is distinguished (located in the right atrium), from which nerve fibers go to the atrioventricular (atrioventricular) node (located in the interventricular septum - the wall between the right and left ventricles). From the atrioventricular node, nerve fibers run in large bundles (right and left bundle branches), dividing into smaller bundles in the walls of the ventricles (Purkinje fibers). An electrical impulse is generated in the sinus node and spreads through the conduction system throughout the myocardium (heart muscle).
Blood supply to the heart.
Like all organs, the heart must receive oxygen. Oxygen is delivered through arteries called coronary arteries. The coronary arteries (right and left) arise from the very beginning of the ascending aorta (at the origin of the aorta from the left ventricle). The trunk of the left coronary artery is divided into the descending artery (also known as the anterior interventricular) and the circumflex artery. These arteries give off branches - the artery of the obtuse edge, diagonal, etc. Sometimes the so-called median artery branches off from the trunk. The branches of the left coronary artery supply blood to the anterior wall of the left ventricle, most of the interventricular septum, the lateral wall of the left ventricle, and the left atrium. The right coronary artery supplies part of the right ventricle and the posterior wall of the left ventricle.
Now that you have become an expert in the anatomy of the cardiovascular system, let’s move on to its diseases.
Coronary heart disease (CHD)
The basis of coronary heart disease is an insufficient supply of oxygen to the heart muscle. That is, there is a discrepancy between demand and delivery. The most common cause of IHD is atherosclerosis of the coronary arteries. An atherosclerotic plaque forms inside the coronary artery, which closes its lumen. With increased stress (physical, psychological stress), the heart requires more oxygen, but its delivery is limited due to partial stenosis (blockage) of the coronary artery. Therefore, the main symptom of angina pectoris is retrosternal (squeezing, pressing) pain during physical activity. The duration of pain is from seconds to minutes (no more than 30 minutes). The pain is usually relieved with nitrates (nitroglycerin). To make a diagnosis of angina, an ECG, stress tests, ECHO CG, 24-hour ECG monitoring, myocardial perfusion scintigraphy, and coronary ventriculography are performed. Angina is divided into stable (angina pectoris, angina at rest) and unstable (progressive, first occurring). A special form of angina is vasospastic (Prince-Menthol), which occurs due to spasm of the coronary arteries. There are three main ways to treat angina - medications (nitrates, b-blockers, angiotensin converting enzyme inhibitors, etc.), balloon angioplasty and coronary artery bypass surgery.
Myocardial infarction
- necrosis (death) of a section of the heart muscle. The causes of myocardial infarction are the same as angina pectoris. The main symptom is prolonged chest pain (more than 30 minutes), which is not relieved by nitrates. The diagnosis of myocardial infarction is made based on the clinical picture, characteristic ECG changes and elevated blood enzyme levels. Treatment is medication (aimed at relieving pain, reducing blood oxygen demand, dilating the coronary arteries); in some cases, within a few hours of the development of a heart attack, it is possible to dissolve a blood clot by administering special drugs (streptokinase, urokinase, etc.). Emergency balloon angioplasty is sometimes performed.
As a result of a myocardial infarction, or due to other diseases (myocarditis), the muscle tissue of the heart is replaced by connective tissue, that is, a scar is formed. Scar changes in the myocardium are called cardiosclerosis .
Disorders of cardiac rhythm and conduction.
Classification
Change in sinus node automaticity:
- sinus bradycardia (slow heart rate),
- sinus tachycardia (accelerated rhythm),
- sinus arrhythmia (irregular rhythm)
Escape rhythms Atrioventricular dissociation Atrial tachycardias Atrioventricular reciprocal tachycardias Ventricular tachycardia Ventricular fibrillation Ventricular preexcitation Sinus node weakness Blocks:
- Sinoatrial
- Atrioventricular
- Bundle branch blocks
Atrial fibrillation and flutter Parasystole
Since it is quite difficult to explain to a non-specialist the essence of these violations, we will decipher only the basic concepts. Extrasystole is an extraordinary contraction of the heart. A distinction is made between atrial extrasystoles (“incorrect” impulse occurs in the atria) and ventricular extrasystoles (“incorrect” impulse occurs in the ventricles). The patient perceives extrasystoles as pauses in the work of the heart. In healthy people, a small amount of extrasitol is recorded per day. Atrial fibrillation (atrial fibrillation) is frequent, chaotic, irregular contraction of the atria and irregular ventricular rhythm. The main causes of atrial fibrillation are damage to the mitral valve, thyrotoxicosis (pathology of the thyroid gland), and cardiosclerosis.
To treat rhythm disturbances, there are several groups of antiarrhythmic drugs; in some cases, pathological foci or nerve pathways are destroyed.
Conduction disorders - delay in the conduction of impulses through the conduction system of the heart - blockade, or vice versa, accelerated conduction of the impulse along additional conduction pathways. Conduction delay is a block; there are sinoauricular, atrioventricular, and bundle branch blocks. Accelerated conduction - WPW (Wolf-Parkinson-White) syndrome is more common.
Hypertonic disease.
The main manifestation of hypertension (HD) is increased blood pressure (BP). This is often manifested by headaches, tinnitus, and flickering of “spots” before the eyes. Hypertension is divided into two large groups - essential (primary) and symptomatic (secondary) hypertension. Essential hypertension is a disease at the level of the whole organism. With secondary hypertension, there is damage to one or another organ, which leads to an increase in blood pressure. Secondary hypertension is divided into renal (glomerulonephritis, pyelonephritis, renovascular hypertension, etc.), endocrine (pheochromocytoma, paraganglioma, Cohn syndrome, Itsenko-Cushing syndrome), vascular (coarthation of the aorta), hypertension with damage to the central nervous system.
When blood pressure increases, changes occur in various organs. The organs most susceptible to the effects of high blood pressure are called target organs. These are the brain, heart, blood vessels, retina, kidneys.
When treating symptomatic hypertension, it is important to eliminate the cause of the increase in blood pressure. The main antihypertensive drugs are b-blockers, angiotensin converting enzyme inhibitors (ACEIs), calcium antagonists, and diuretics.
Heart defects
Heart defects are divided into congenital and acquired. There are quite a large number of names that are congenital; we will not list them all; we will pay attention to the most common ones. These are patent oval window (ventricular septal defect), atrial septal defect, tetralogy and Fallot's triad. Treatment is surgical. Mitral valve prolapse is insufficiency of the mitral valve caused by the “bending” of its valves into the cavity of the left atrium during contraction (systole) of the left ventricle. The reason is connective tissue disorders.
Acquired defects include stenosis (incomplete opening) or insufficiency (incomplete closure) of the heart valves. Stenosis or insufficiency of the mitral and tricuspid valves are more common. The cause of the lesion is rheumatism, endocarditis, atherosclerosis, etc. Treatment is surgical, in the acute phase - antibiotic therapy, hormones, cytostatics, etc.
Primary damage to the heart muscle
Myocarditis Endocarditis Pericarditis Cardiomyopathies
- Dilatational
- Hypertrophic
- Restrictive
Myocarditis is an inflammation of the heart muscle, it can be bacterial, viral, or allergic. This is a rather “complex” disease, since an autoimmune reaction is triggered - antibodies are produced to one’s own muscle. Treatment: antibiotics, hormonal drugs, hydroxyquinolines. Endocarditis is inflammation of the endocardium, often bacterial. Ultimately leads to damage to the heart valves. Treatment: antibiotics, hormones.
Dilated cardiomyopathy is a lesion of the heart muscle, which causes expansion of the heart (enlargement of cavities) and thinning of its walls. The heart's ability to pump blood decreases. The reason is not fully understood. The main manifestation is the occurrence of circulatory failure - shortness of breath, swelling, enlarged liver, attacks of suffocation. Weakness, cardiac arrhythmias, and thromboembolism are common.
Hypertrophic cardiomyopathy is a thickening of the heart muscle, resulting in difficulty ejecting blood from the left ventricle. The reason is not fully understood. The main manifestation is rhythm and conduction disturbances, pain in the heart, weakness.
Restrictive cardiomyopathy is a reduction in the chambers of the heart.
Cor pulmonale is an overload of the heart that occurs due to increased resistance in the vessels of the lungs. The reason for this is primary pulmonary hypertension (primary damage to the blood vessels of the lungs), chronic pulmonary diseases (pneumosclerosis, emphysema, bronchiectasis, bronchitis, etc.) and anatomical changes in the chest. Thromboembolism is blockage of blood vessels by blood clots. The most dangerous is thromboembolism of the pulmonary artery and its branches.
Peripheral arterial diseases:
- Arterial stenosis and occlusion
- Arterial aneurysms
- Raynaud's disease (syndrome)
- Peripheral venous diseases
- Peripheral vein thrombosis
- Phlebitis
- Varicose veins
