The heart of man and higher mammals consists of four chambers: two atria and two ventricles. According to the location of the ventricles, like the atria, are divided into right and left.
The left ventricle is the beginning of the systemic circulation.
Anatomy
The message of the left ventricle and the left atrium is carried out through the left atrioventricular orifice, from the right ventricle the ventriculus sinister is completely isolated by the interventricular septum. The aorta emerges from this chamber of the heart, through it the blood, which is enriched with oxygen, through smaller arteries enters the internal organs.
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 that of 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 are ten to fifteen millimeters thick, which is several times greater than those of 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 thickerheart wall. The left ventricle pushes the blood involved in the systemic circulation, while the right ventricle provides the volume of blood for the pulmonary circulation. That is why, under normal conditions, the latter is less developed, and its thickness, accordingly, is less.
The atrioventricular communication (orifice) on the left side is closed by the mitral valve, consisting of the posterior and anterior leaflets. In this case, the anterior one is located in close proximity to the interventricular septum, and the posterior one is outside of it.
Chords depart from both valves - tendon threads that attach the valves to the papillary muscles. Due to these muscles, the valve 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 the apex of the heart, but 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 semilunar valve is located at the exit of the aorta, thanks to which blood does not return fromaorta in the heart.
The nerve impulse to the left ventricular myocardium comes through the Hiss bundle (its left leg). It is worth noting that the impulse is sent only to the left ventricle through two branches - anterior and posterior.
Features of the left ventricle and its functions
Relative to other parts of the heart, the left ventricle is located downward, behind and to the left. Its outer edge is somewhat rounded and is called the pulmonary surface. In the course of life, the volume of this chamber increases from 5.5 cm3 (for newborns) to 210 cm3 (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 than it.
There are several departments in the structure of the left ventricle:
- The anterior (arterial cone) communicates with the aorta through the arterial orifice.
- Posterior (ventricular cavity proper), which communicates with the right atrium.
As mentioned above, due to the more developed myocardium, the thickness of the left ventricular wall is eleven to fourteen millimeters.
The function of the left ventricle is to eject oxygen-enriched blood into the aorta (respectively, into the systemic circulation), and then through a network of smaller arteries and capillaries, organs and tissues of the whole organism are nourished.
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 contraction;
- Exile: Includes fast and slow exile.
Asynchronous tension is characterized by uneven contraction of myocardial muscle fibers, due to uneven distribution of excitation. The atrioventricular valve is closed at this time. After the excitation covers all myocardial fibers, and the pressure in the ventricles increases, the valve closes and the cavity closes.
After the blood pressure acting on the walls of the ventricle increases to eighty mm Hg. Art., and the difference with pressure on the aorta is 2 mm Hg. Art., the semilunar valve opens, and blood rushes into the aorta. When reverse blood flow occurs from the aorta, the semilunar valves close.
After that, the ventricular myocardium relaxes and blood enters the ventricle through the mitral valve from the atrium. The process then repeats.
Left ventricular dysfunction
Distinguish between systolic and diastolic dysfunction of a given chamber of the heart.
Systolic dysfunction reduces the ability of the ventricle to push blood out of the cavity into the aorta, the most common cause of heart failure.
This dysfunction is usually caused by a decrease in contractility, resulting in a decrease in stroke volume.
Diastolic dysfunction of the left ventricle is a decrease in its ability to fill its cavity with blood (i.e.ensuring diastolic filling). This condition can lead to secondary hypertension (both venous and arterial), accompanied by shortness of breath, cough and paroxysmal nocturnal dyspnea.
Heart defects
There are acquired and congenital. The latter are the result of developmental disorders in the embryonic period. The category of congenital malformations includes malformed valves, additional ones in the left ventricle or with an inappropriate chord length, an open septum between the ventricles, transposition (abnormal arrangement) of the great vessels.
If a child has a ventricular or atrial septal defect, venous and arterial blood mixes. Children with similar malformations, when combined with vascular transposition, have bluish skin, which is the only symptom at first.
If transposition is present as an isolated defect, then hypoxia leads to instant death. In some cases (if a defect is detected before birth), an operation is possible.
Surgical treatment is also necessary for other defects of the left ventricle (for example, defects of the aortic valve or mitral valve).
Left ventricular hypertrophy
Characterized by thickening of the wall of the ventricle.
The reasons for this condition may be:
- Permanent long training (professional sports).
- Inactivity.
- Smoking tobacco.
- Alcoholism.
- Farby disease.
- Muscular dystrophy.
- Stress.
- Pathologies of peripheral vessels.
- Obesity.
- Atherosclerosis.
- Diabetes mellitus.
- Ischemia.
- Hypertension.
In the beginning, the disease is asymptomatic, and as the process progresses, cardialgia, fainting, dizziness, and fatigue occur. Then joins heart failure, characterized by shortness of breath (including at rest).
Left ventricular failure
Often appearing in the background:
- Aortic malformations.
- Glomerulonephritis.
- Hypertension.
- Myocardial infarction.
- Syphilitic aortitis.
- Cardiosclerosis atherosclerotic.
This pathology is characterized by increasing cyanosis, shortness of breath, weakness, pain in the heart, disruption of other organs, and so on.
Diagnosis of pathologies of the left ventricle
- Ultrasound (definition of birth defects);
- ECG;
- MRI;
- CT;
- chest x-ray;
- FCG;
- echoCG.
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. Exceptmedicines, diet and bad habits, weight loss and s alt reduction are recommended.
The diet should be enriched with fermented milk and dairy products, fruits, seafood and vegetables. In addition, it is mandatory to reduce the amount of fats, sweets and starchy foods. Moderate exercise recommended.
In addition to conservative therapy, surgical treatment is also used to remove a section of hypertrophied myocardium. It must be remembered that this pathology develops over several years.
If we are talking about left ventricular failure, then in this case special "heart" drugs are used: "Korglikon", "Korazol", "Strophanthin", "Camphor", "Cordiamin", as well as oxygen inhalations and bed rest.
