The heart of man and higher mammals consists of four chambers: two atria and two ventricles. According to the location of the ventricle, as well as the atria, are divided into right and left.
The left ventricle is the beginning of a large circle of blood circulation.
Anatomy
The message of the left ventricle and the left atrium is carried out through the left atrioventricular opening, and the ventriculus sinister is completely isolated from the right ventricle by the interventricular septum. An aorta emerges from this chamber of the heart , through it blood, which is enriched with oxygen, enters the internal organs through smaller arteries.
The left ventricle looks like an inverted cone, and the only one of all the chambers takes part in the formation of the apex of the heart. Due to its larger size than the right ventricle, it is believed that the heart is located on the left, although in fact it occupies almost the center of the chest.
The walls of the left ventricle have a thickness of ten to fifteen millimeters, which is several times more than similar indicators at the wall of the right ventricle. This is due to a more developed myocardium on the left side due to higher loads. That is, the higher the volume of work performed, the thicker the heart wall. The left ventricle pushes blood involved in a large circle of blood circulation, while the right ventricle provides blood volume for a small circle. That is why under normal conditions the latter is less developed, and its thickness, respectively, is less.
The atrioventricular communication (opening) on the left side is closed by a mitral valve consisting of the posterior and anterior valves. In this case, the anterior is located in the immediate vicinity of the interventricular septum, and the posterior is located outside of it.
Chords, tendon filaments, attaching the valves to the papillary muscles, extend from both wings. Due to these muscles, the valve also performs its functions, that is, during systole, blood does not return back to the atrium.
The papillary muscles are attached to special myocardial protrusions (fleshy trabeculae), which are located on the inner plane of the ventricle. Such trabeculae are especially developed in the region of the interventricular septum and apex of the heart, however, their number in the ventricle on the left is less than on the right.
The length and number of chords of the left ventricle are individual.
With age, their length gradually increases, being inversely related to the length of the papillary muscles. Most often, the chords that come from one muscle are attached to one leaf. In addition, chords are found that connect the papillary muscles to the trabeculae.
A lunar valve is located at the exit site of the aorta , due to which blood does not return from the aorta to the heart.
A nerve impulse to the left ventricular myocardium enters through the bundle of His (his left leg). It is worth noting that only to the left ventricle, the impulse is sent through two branches - the front and the back.
Features of the left ventricle and its functions
Relative to other parts of the heart, the left ventricle is located down, back and left. Its outer edge is somewhat rounded and is called the pulmonary surface. In the process of life, the volume of this chamber increases from 5.5 cm 3 (for newborns) to 210 cm 3 (by eighteen to twenty-five years).
Compared to the right, the left ventricle has a more pronounced oval-oblong shape, much more muscular and slightly longer.
In the structure of the left ventricle, several departments are distinguished:
- The anterior (arterial cone) communicates with the aorta through the arterial opening.
- The posterior (actually the cavity of the ventricle), which communicates with the right atrium.
As mentioned above, due to a more developed myocardium, the thickness of the left ventricular wall is eleven to fourteen millimeters.
The function of the left ventricle is the release of oxygen-enriched blood into the aorta (respectively, into the large circle of blood circulation), and then through the network of smaller arteries and capillaries, the organs and tissues of the whole body are fed.
Physiology
Under normal conditions, the left and right ventricles function synchronously. Their work occurs in two phases: systole and diastole (respectively, contraction and relaxation). Systole, in turn, is divided into two periods:
- Voltage: includes asynchronous and isometric reduction;
- Exile: includes fast and slow exile.
Asynchronous tension is characterized by an uneven contraction of the myocardial muscle fibers, due to the uneven distribution of excitation. The atrioventricular valve is closed at this time. After the excitation covers all the fibers of the myocardium, and the pressure in the ventricles increases, the valve closes and the cavity closes.
After acting on the walls of the ventricle, blood pressure rises to eighty mm RT. Art., and the difference with pressure on the aorta is 2 mm RT. Art., lunar valve opens, and blood rushes into the aorta. When reverse blood flow from the aorta occurs, the valves of the lunar valves are slammed shut.
After this, the ventricular myocardium relaxes and through the mitral valve from the atrium, blood enters the ventricle. Then the process is repeated.
Left ventricular dysfunction
Systolic and diastolic dysfunctions of this heart chamber are distinguished.
With systolic dysfunction, the ventricle’s ability to push blood from the cavity into the aorta decreases, which is the most common cause of heart failure.
Such dysfunction, as a rule, occurs due to a decrease in contractility, which leads to a decrease in stroke volume.
Diastolic dysfunction of the left ventricle is a decrease in its ability to fill its cavity with blood (that is, ensuring diastolic filling). This condition can lead to secondary hypertension (both venous and arterial), which is accompanied by shortness of breath, cough and paroxysmal nocturnal dyspnea.
Heart defects
They are acquired and congenital. The latter are a consequence of developmental disorders in the embryonic period. Incorrectly formed valves are included in the category of congenital malformations, additional in the left ventricle or with an inappropriate chord length, an unshielded septum between the ventricles, transposition (anomalous location) of the great vessels.
If the child has a defect in the interventricular or interatrial septum, the venous and arterial blood mix. Children with similar defects, when combined with vascular transposition, have bluish skin, which at first is the only symptom.
If transposition is present as an isolated defect, then hypoxia leads to the onset of instant death. In some cases (if a defect is detected before birth), surgery is possible.
Surgical treatment is also necessary for other defects of the left ventricle (for example, malformations of the aortic valve or mitral valve).
Left ventricular hypertrophy
It is characterized by compaction of the wall of the ventricle.
The causes of this condition may be:
- Constant long training (professional sport).
- Lack of exercise.
- Smoking tobacco.
- Alcoholism.
- Farby's disease.
- Muscular dystrophy.
- Stress.
- Pathology of peripheral vessels.
- Obesity.
- Atherosclerosis.
- Diabetes.
- Ischemia.
- Hypertension.
At first, the disease is asymptomatic, and as the process progresses, cardialgia, fainting, dizziness, and fatigue occur. Then, heart failure, characterized by shortness of breath (including at rest), joins.
Left ventricular failure
Often occurs against the background of:
- Aortic malformations.
- Glomerulonephritis.
- Hypertension.
- Myocardial infarction.
- Syphilitic aortitis.
- Atherosclerotic cardiosclerosis.
This pathology is characterized by increasing cyanosis, shortness of breath, weakness, pain in the heart, impaired functioning of other organs, and so on.
Diagnosis of pathologies of the left ventricle
- Ultrasound (definition of congenital malformations);
- ECG;
- MRI
- CT
- chest x-ray;
- FCG;
- echocardiography.
How to treat the left ventricle of the heart
As mentioned above, heart defects most often require surgical treatment.
Left ventricular hypertrophy can be treated with a combination of beta-blockers and Verapamil. This method allows to reduce the clinical manifestations of pathology. In addition to medicines, it is recommended to follow a diet and abandon bad habits, reduce weight and reduce the amount of salt consumed.
The diet should be enriched with dairy and dairy products, fruits, seafood and vegetables. In addition, it is mandatory to reduce the amount of fat, sweets and flour. Moderate exercise is recommended.
In addition to conservative therapy, surgical treatment is also used to remove a portion of the hypertrophic myocardium. It must be remembered that this pathology develops over several years.
If we are talking about left ventricular failure, then in this case they use special “heart” preparations: “Korglikon”, “Korazol”, “Strofantin”, “Camphor”, “Cordiamin”, as well as oxygen inhalation and bed rest.